From 09831c7eedf8eeb5a8b232d464b1b8bf7e8591d9 Mon Sep 17 00:00:00 2001
From: Steve Boyd <emteknetnz@gmail.com>
Date: Wed, 5 Jun 2024 18:14:23 +1200
Subject: [PATCH] ENH Use class name instead of self

---
 src/Control/ContentNegotiator.php             |   2 +-
 src/Control/Controller.php                    |   8 +-
 src/Control/Cookie.php                        |  18 +--
 src/Control/Director.php                      |  60 +++++-----
 src/Control/Email/Email.php                   |   6 +-
 src/Control/HTTP.php                          |   6 +-
 src/Control/HTTPRequest.php                   |   2 +-
 src/Control/HTTPResponse.php                  |   8 +-
 .../Middleware/HTTPCacheControlMiddleware.php |  38 +++---
 src/Control/RequestHandler.php                |   4 +-
 src/Control/Session.php                       |   2 +-
 src/Control/Util/IPUtils.php                  |   2 +-
 src/Core/BaseKernel.php                       |   6 +-
 src/Core/ClassInfo.php                        |  46 +++----
 src/Core/Config/Config.php                    |   2 +-
 src/Core/Config/ConfigLoader.php              |   8 +-
 src/Core/Convert.php                          |  20 ++--
 src/Core/Environment.php                      |   2 +-
 src/Core/Extensible.php                       |   2 +-
 src/Core/Injector/Injector.php                |  14 +--
 src/Core/Injector/InjectorLoader.php          |  10 +-
 src/Core/Manifest/ClassLoader.php             |   2 +-
 src/Core/Manifest/ManifestFileFinder.php      |  14 +--
 src/Core/Manifest/ModuleLoader.php            |   6 +-
 src/Core/Manifest/ModuleManifest.php          |   2 +-
 src/Core/Manifest/VersionProvider.php         |   2 +-
 src/Core/Path.php                             |   4 +-
 src/Dev/Backtrace.php                         |  14 +--
 src/Dev/BulkLoader.php                        |  14 +--
 src/Dev/CLI.php                               |  10 +-
 src/Dev/CliDebugView.php                      |  24 ++--
 src/Dev/CsvBulkLoader.php                     |   4 +-
 src/Dev/Debug.php                             |   4 +-
 src/Dev/DebugView.php                         |   4 +-
 src/Dev/Deprecation.php                       |  62 +++++-----
 src/Dev/Install/DatabaseAdapterRegistry.php   |  14 +--
 src/Dev/SapphireTest.php                      |  12 +-
 src/Dev/TestKernel.php                        |   4 +-
 .../Validation/RelationValidationService.php  |   6 +-
 src/Forms/ConfirmedPasswordField.php          |   2 +-
 src/Forms/Form.php                            |  22 ++--
 src/Forms/FormFactory.php                     |   2 +-
 src/Forms/FormField.php                       |   6 +-
 src/Forms/GridField/GridField.php             |   6 +-
 src/Forms/GridField/GridFieldDetailForm.php   |   2 +-
 src/Forms/GridField/GridFieldFilterHeader.php |   2 +-
 src/Forms/GridField/GridState_Data.php        |   6 +-
 src/Forms/HTMLEditor/HTMLEditorConfig.php     |  24 ++--
 src/Forms/HTMLEditor/TinyMCEConfig.php        |  10 +-
 src/Forms/HTMLReadonlyField.php               |   2 +-
 src/Forms/HeaderField.php                     |   2 +-
 src/Forms/LiteralField.php                    |   2 +-
 src/Forms/SingleSelectField.php               |   2 +-
 src/Forms/TextField.php                       |   2 +-
 src/Forms/Tip.php                             |  14 +--
 src/Forms/TreeDropdownField.php               |  12 +-
 src/ORM/ArrayLib.php                          |   4 +-
 src/ORM/Connect/DBQueryBuilder.php            |   2 +-
 src/ORM/Connect/Database.php                  |  10 +-
 src/ORM/Connect/MySQLQueryBuilder.php         |   2 +-
 src/ORM/Connect/MySQLSchemaManager.php        |  14 +--
 src/ORM/Connect/MySQLiConnector.php           |   2 +-
 src/ORM/Connect/NullDatabase.php              |   4 +-
 src/ORM/DB.php                                |  74 ++++++------
 src/ORM/DataObject.php                        | 112 +++++++++---------
 src/ORM/DataObjectSchema.php                  |  16 +--
 src/ORM/DataQuery.php                         |   2 +-
 src/ORM/EagerLoadedList.php                   |   6 +-
 src/ORM/FieldType/DBDate.php                  |  16 +--
 src/ORM/FieldType/DBDatetime.php              |  18 +--
 src/ORM/FieldType/DBEnum.php                  |  12 +-
 src/ORM/FieldType/DBField.php                 |   2 +-
 src/ORM/FieldType/DBForeignKey.php            |   2 +-
 src/ORM/FieldType/DBString.php                |   2 +-
 src/ORM/FieldType/DBTime.php                  |   2 +-
 src/ORM/Filters/SearchFilter.php              |   8 +-
 src/ORM/Hierarchy/Hierarchy.php               |  18 +--
 src/ORM/Hierarchy/MarkedSet.php               |   2 +-
 src/ORM/ListDecorator.php                     |   2 +-
 src/ORM/Queries/SQLConditionalExpression.php  |   4 +-
 src/ORM/Queries/SQLSelect.php                 |   2 +-
 src/ORM/Search/FulltextSearchable.php         |   4 +-
 src/ORM/Search/SearchContext.php              |   2 +-
 src/ORM/ValidationResult.php                  |  14 +--
 src/Security/BasicAuth.php                    |  10 +-
 src/Security/Confirmation/Storage.php         |   4 +-
 src/Security/InheritedPermissions.php         |  56 ++++-----
 src/Security/LogoutForm.php                   |   2 +-
 src/Security/Member.php                       |  14 +--
 .../MemberAuthenticator/MemberLoginForm.php   |   4 +-
 src/Security/PasswordEncryptor.php            |   4 +-
 src/Security/PasswordEncryptor_Blowfish.php   |   8 +-
 src/Security/Permission.php                   |  30 ++---
 src/Security/RememberLoginHash.php            |   4 +-
 src/Security/Security.php                     |  34 +++---
 src/Security/SecurityToken.php                |  20 ++--
 src/Security/SudoMode/SudoModeService.php     |   4 +-
 src/View/Embed/EmbedContainer.php             |   2 +-
 src/View/Parsers/HtmlDiff.php                 |  42 +++----
 src/View/Parsers/SQLFormatter.php             |   2 +-
 src/View/Parsers/ShortcodeParser.php          |  52 ++++----
 src/View/Requirements.php                     |  84 ++++++-------
 src/View/SSViewer.php                         |  22 ++--
 src/View/SSViewer_DataPresenter.php           |  16 +--
 src/View/SSViewer_Scope.php                   |   6 +-
 .../Shortcodes/EmbedShortcodeProvider.php     |  14 +--
 src/View/ThemeManifest.php                    |   2 +-
 src/View/ThemeResourceLoader.php              |   6 +-
 src/View/ViewableData.php                     |   8 +-
 src/i18n/TextCollection/i18nTextCollector.php |  14 +--
 src/i18n/i18n.php                             |  12 +-
 tests/behat/src/CmsUiContext.php              |   2 +-
 .../FlushMiddlewareTest/TestFlushable.php     |   2 +-
 tests/php/Control/RSS/RSSFeedTest.php         |   6 +-
 .../ControllerExtension.php                   |   4 +-
 .../DevAdminControllerTest/Controller1.php    |   4 +-
 .../ControllerWithPermissions.php             |   2 +-
 .../php/Dev/SapphireTestTest/DataProvider.php |  32 ++---
 .../Logging/DetailedErrorFormatterTest.php    |   2 +-
 tests/php/ORM/DataListEagerLoadingTest.php    |   8 +-
 .../MockDynamicAssignmentDataObject.php       |   4 +-
 tests/php/ORM/DataObjectTest/TreeNode.php     |   8 +-
 tests/php/ORM/Filters/EndsWithFilterTest.php  |   3 +-
 .../php/ORM/Filters/ExactMatchFilterTest.php  |   3 +-
 .../ORM/Filters/PartialMatchFilterTest.php    |   3 +-
 .../php/ORM/Filters/StartsWithFilterTest.php  |   3 +-
 tests/php/ORM/MarkedSetTest.php               |   4 +-
 tests/php/ORM/MySQLiConnectorTest.php         |   2 +-
 tests/php/ORM/RelatedDataServiceTest.php      |   4 +-
 .../ORM/SQLSelectTest/CteRecursiveObject.php  |   4 +-
 .../TestCacheFlusher.php                      |   2 +-
 .../TestPermissionNode.php                    |   2 +-
 .../InheritedPermissionsTest/UnstagedNode.php |   2 +-
 tests/php/View/RequirementsTest.php           |  32 ++---
 tests/php/View/SSViewerTest/LevelTestData.php |   2 +-
 tests/php/i18n/i18nTest/TestObject.php        |   4 +-
 thirdparty/php-peg/Compiler.php               |  34 +++---
 137 files changed, 801 insertions(+), 797 deletions(-)

diff --git a/src/Control/ContentNegotiator.php b/src/Control/ContentNegotiator.php
index 21ec89f3e6b..aeb3b9f54a8 100644
--- a/src/Control/ContentNegotiator.php
+++ b/src/Control/ContentNegotiator.php
@@ -116,7 +116,7 @@ public static function setEnabled($enabled)
      */
     public static function process(HTTPResponse $response)
     {
-        if (!self::enabled_for($response)) {
+        if (!ContentNegotiator::enabled_for($response)) {
             return;
         }
 
diff --git a/src/Control/Controller.php b/src/Control/Controller.php
index 80d7047c06c..5b94f0ad694 100644
--- a/src/Control/Controller.php
+++ b/src/Control/Controller.php
@@ -573,7 +573,7 @@ public function pushCurrent()
     {
         // Ensure this controller has a valid session
         $this->getRequest()->getSession();
-        array_unshift(self::$controller_stack, $this);
+        array_unshift(Controller::$controller_stack, $this);
     }
 
     /**
@@ -581,8 +581,8 @@ public function pushCurrent()
      */
     public function popCurrent()
     {
-        if ($this === self::$controller_stack[0]) {
-            array_shift(self::$controller_stack);
+        if ($this === Controller::$controller_stack[0]) {
+            array_shift(Controller::$controller_stack);
         } else {
             $class = static::class;
             user_error(
@@ -693,7 +693,7 @@ public static function normaliseTrailingSlash(string $url): string
         }
 
         // Normlise trailing slash
-        $shouldHaveTrailingSlash = self::config()->uninherited('add_trailing_slash');
+        $shouldHaveTrailingSlash = Controller::config()->uninherited('add_trailing_slash');
         if ($shouldHaveTrailingSlash
             && !str_ends_with($url, '/')
             && !preg_match('/^(.*)\.([^\/]*)$/', Director::makeRelative($url))
diff --git a/src/Control/Cookie.php b/src/Control/Cookie.php
index 2995e844f9e..2bcafa606de 100644
--- a/src/Control/Cookie.php
+++ b/src/Control/Cookie.php
@@ -31,7 +31,7 @@ class Cookie
      * Must be "Strict", "Lax", or "None"
      * @config
      */
-    private static string $default_samesite = self::SAMESITE_LAX;
+    private static string $default_samesite = Cookie::SAMESITE_LAX;
 
     /**
      * Fetch the current instance of the cookie backend.
@@ -67,7 +67,7 @@ public static function set(
         $secure = false,
         $httpOnly = true
     ) {
-        return self::get_inst()->set($name, $value, $expiry, $path, $domain, $secure, $httpOnly);
+        return Cookie::get_inst()->set($name, $value, $expiry, $path, $domain, $secure, $httpOnly);
     }
 
     /**
@@ -80,7 +80,7 @@ public static function set(
      */
     public static function get($name, $includeUnsent = true)
     {
-        return self::get_inst()->get($name, $includeUnsent);
+        return Cookie::get_inst()->get($name, $includeUnsent);
     }
 
     /**
@@ -92,7 +92,7 @@ public static function get($name, $includeUnsent = true)
      */
     public static function get_all($includeUnsent = true)
     {
-        return self::get_inst()->getAll($includeUnsent);
+        return Cookie::get_inst()->getAll($includeUnsent);
     }
 
     /**
@@ -104,7 +104,7 @@ public static function get_all($includeUnsent = true)
      */
     public static function force_expiry($name, $path = null, $domain = null, $secure = false, $httpOnly = true)
     {
-        return self::get_inst()->forceExpiry($name, $path, $domain, $secure, $httpOnly);
+        return Cookie::get_inst()->forceExpiry($name, $path, $domain, $secure, $httpOnly);
     }
 
     /**
@@ -116,14 +116,14 @@ public static function force_expiry($name, $path = null, $domain = null, $secure
     public static function validateSameSite(string $sameSite): void
     {
         $validValues = [
-            self::SAMESITE_STRICT,
-            self::SAMESITE_LAX,
-            self::SAMESITE_NONE,
+            Cookie::SAMESITE_STRICT,
+            Cookie::SAMESITE_LAX,
+            Cookie::SAMESITE_NONE,
         ];
         if (!in_array($sameSite, $validValues)) {
             throw new LogicException('Cookie samesite must be "Strict", "Lax", or "None"');
         }
-        if ($sameSite === self::SAMESITE_NONE && !Director::is_https(self::getRequest())) {
+        if ($sameSite === Cookie::SAMESITE_NONE && !Director::is_https(Cookie::getRequest())) {
             Injector::inst()->get(LoggerInterface::class)->warning('Cookie samesite cannot be "None" for non-https requests.');
         }
     }
diff --git a/src/Control/Director.php b/src/Control/Director.php
index f91fc93b478..ce7654edb3d 100644
--- a/src/Control/Director.php
+++ b/src/Control/Director.php
@@ -238,7 +238,7 @@ public static function mockRequest(
 
         // Ensure URL is properly made relative.
         // Example: url passed is "/ss31/my-page" (prefixed with BASE_URL), this should be changed to "my-page"
-        $url = self::makeRelative($url);
+        $url = Director::makeRelative($url);
         if (strpos($url ?? '', '?') !== false) {
             list($url, $getVarsEncoded) = explode('?', $url ?? '', 2);
             parse_str($getVarsEncoded ?? '', $newVars['_GET']);
@@ -371,7 +371,7 @@ public function handleRequest(HTTPRequest $request)
      */
     public static function get_current_page()
     {
-        return self::$current_page ? self::$current_page : Controller::curr();
+        return Director::$current_page ? Director::$current_page : Controller::curr();
     }
 
     /**
@@ -381,7 +381,7 @@ public static function get_current_page()
      */
     public static function set_current_page($page)
     {
-        self::$current_page = $page;
+        Director::$current_page = $page;
     }
 
     /**
@@ -394,7 +394,7 @@ public static function set_current_page($page)
      *     - REQUEST - Resolve this path to the current url (i.e. behaves as though no `<base>` tag is provided in a html document)
      *     - ROOT - Treat this as though it was an absolute path, and append it to the protocol and hostname.
      */
-    public static function absoluteURL(string $url, string $relativeParent = self::BASE): string|bool
+    public static function absoluteURL(string $url, string $relativeParent = Director::BASE): string|bool
     {
         // Check if there is already a protocol given
         if (preg_match('/^http(s?):\/\//', $url ?? '')) {
@@ -404,14 +404,14 @@ public static function absoluteURL(string $url, string $relativeParent = self::B
         // Absolute urls without protocol are added
         // E.g. //google.com -> http://google.com
         if (strpos($url ?? '', '//') === 0) {
-            return Controller::normaliseTrailingSlash(self::protocol() . substr($url ?? '', 2));
+            return Controller::normaliseTrailingSlash(Director::protocol() . substr($url ?? '', 2));
         }
 
         // Determine method for mapping the parent to this relative url
-        if ($relativeParent === self::ROOT || self::is_root_relative_url($url)) {
+        if ($relativeParent === Director::ROOT || Director::is_root_relative_url($url)) {
             // Root relative urls always should be evaluated relative to the root
-            $parent = self::protocolAndHost();
-        } elseif ($relativeParent === self::REQUEST) {
+            $parent = Director::protocolAndHost();
+        } elseif ($relativeParent === Director::REQUEST) {
             // Request relative urls rely on the REQUEST_URI param (old default behaviour)
             if (!isset($_SERVER['REQUEST_URI'])) {
                 return false;
@@ -419,7 +419,7 @@ public static function absoluteURL(string $url, string $relativeParent = self::B
             $parent = dirname($_SERVER['REQUEST_URI'] . 'x');
         } else {
             // Default to respecting site base_url
-            $parent = self::absoluteBaseURL();
+            $parent = Director::absoluteBaseURL();
         }
 
         // Map empty urls to relative slash and join to base
@@ -489,7 +489,7 @@ protected static function validateUserAndPass($url)
     public static function host(HTTPRequest $request = null)
     {
         // Check if overridden by alternate_base_url
-        if ($baseURL = self::config()->get('alternate_base_url')) {
+        if ($baseURL = Director::config()->get('alternate_base_url')) {
             $baseURL = Injector::inst()->convertServiceProperty($baseURL);
             $host = static::parseHost($baseURL);
             if ($host) {
@@ -508,7 +508,7 @@ public static function host(HTTPRequest $request = null)
         }
 
         // Check base url
-        if ($baseURL = self::config()->uninherited('default_base_url')) {
+        if ($baseURL = Director::config()->uninherited('default_base_url')) {
             $baseURL = Injector::inst()->convertServiceProperty($baseURL);
             $host = static::parseHost($baseURL);
             if ($host) {
@@ -566,7 +566,7 @@ public static function protocolAndHost(HTTPRequest $request = null)
      */
     public static function protocol(HTTPRequest $request = null)
     {
-        return (self::is_https($request)) ? 'https://' : 'http://';
+        return (Director::is_https($request)) ? 'https://' : 'http://';
     }
 
     /**
@@ -578,7 +578,7 @@ public static function protocol(HTTPRequest $request = null)
     public static function is_https(HTTPRequest $request = null)
     {
         // Check override from alternate_base_url
-        if ($baseURL = self::config()->uninherited('alternate_base_url')) {
+        if ($baseURL = Director::config()->uninherited('alternate_base_url')) {
             $baseURL = Injector::inst()->convertServiceProperty($baseURL);
             $protocol = parse_url($baseURL ?? '', PHP_URL_SCHEME);
             if ($protocol) {
@@ -593,7 +593,7 @@ public static function is_https(HTTPRequest $request = null)
         }
 
         // Check default_base_url
-        if ($baseURL = self::config()->uninherited('default_base_url')) {
+        if ($baseURL = Director::config()->uninherited('default_base_url')) {
             $baseURL = Injector::inst()->convertServiceProperty($baseURL);
             $protocol = parse_url($baseURL ?? '', PHP_URL_SCHEME);
             if ($protocol) {
@@ -612,7 +612,7 @@ public static function is_https(HTTPRequest $request = null)
     public static function baseURL()
     {
         // Check override base_url
-        $alternate = self::config()->get('alternate_base_url');
+        $alternate = Director::config()->get('alternate_base_url');
         if ($alternate) {
             $alternate = Injector::inst()->convertServiceProperty($alternate);
             return rtrim(parse_url($alternate ?? '', PHP_URL_PATH) ?? '', '/') . '/';
@@ -659,8 +659,8 @@ public static function publicDir()
      */
     public static function publicFolder()
     {
-        $folder = self::baseFolder();
-        $publicDir = self::publicDir();
+        $folder = Director::baseFolder();
+        $publicDir = Director::publicDir();
         if ($publicDir) {
             return Path::join($folder, $publicDir);
         }
@@ -694,7 +694,7 @@ public static function makeRelative($url)
         }
 
         // Remove base folder or url
-        foreach ([self::publicFolder(), self::baseFolder(), self::baseURL()] as $base) {
+        foreach ([Director::publicFolder(), Director::baseFolder(), Director::baseURL()] as $base) {
             // Ensure single / doesn't break comparison (unless it would make base empty)
             $base = rtrim($base ?? '', '\\/') ?: $base;
             if (stripos($url ?? '', $base ?? '') === 0) {
@@ -827,7 +827,7 @@ public static function is_site_url($url)
         }
 
         // Relative urls always are site urls
-        return self::is_relative_url($url);
+        return Director::is_relative_url($url);
     }
 
     /**
@@ -840,20 +840,20 @@ public static function is_site_url($url)
     public static function getAbsFile($file)
     {
         // If already absolute
-        if (self::is_absolute($file)) {
+        if (Director::is_absolute($file)) {
             return $file;
         }
 
         // If path is relative to public folder search there first
-        if (self::publicDir()) {
-            $path = Path::join(self::publicFolder(), $file);
+        if (Director::publicDir()) {
+            $path = Path::join(Director::publicFolder(), $file);
             if (file_exists($path ?? '')) {
                 return $path;
             }
         }
 
         // Default to base folder
-        return Path::join(self::baseFolder(), $file);
+        return Path::join(Director::baseFolder(), $file);
     }
 
     /**
@@ -877,9 +877,9 @@ public static function fileExists($file)
      */
     public static function absoluteBaseURL()
     {
-        $baseURL = self::absoluteURL(
-            self::baseURL(),
-            self::ROOT
+        $baseURL = Director::absoluteURL(
+            Director::baseURL(),
+            Director::ROOT
         );
         return Controller::normaliseTrailingSlash($baseURL);
     }
@@ -986,7 +986,7 @@ public static function forceWWW(HTTPRequest $request = null)
      */
     public static function is_ajax(HTTPRequest $request = null)
     {
-        $request = self::currentRequest($request);
+        $request = Director::currentRequest($request);
         if ($request) {
             return $request->isAjax();
         }
@@ -1054,7 +1054,7 @@ public static function get_session_environment_type(HTTPRequest $request = null)
      */
     public static function isLive()
     {
-        return self::get_environment_type() === 'live';
+        return Director::get_environment_type() === 'live';
     }
 
     /**
@@ -1065,7 +1065,7 @@ public static function isLive()
      */
     public static function isDev()
     {
-        return self::get_environment_type() === 'dev';
+        return Director::get_environment_type() === 'dev';
     }
 
     /**
@@ -1076,7 +1076,7 @@ public static function isDev()
      */
     public static function isTest()
     {
-        return self::get_environment_type() === 'test';
+        return Director::get_environment_type() === 'test';
     }
 
     /**
diff --git a/src/Control/Email/Email.php b/src/Control/Email/Email.php
index 21420d61f09..52b05dc944f 100644
--- a/src/Control/Email/Email.php
+++ b/src/Control/Email/Email.php
@@ -104,10 +104,10 @@ private static function mergeConfiguredAddresses(string $configKey, string $envK
     {
         $addresses = [];
         $config = (array) static::config()->get($configKey);
-        $addresses = self::convertConfigToAddreses($config);
+        $addresses = Email::convertConfigToAddreses($config);
         $env = Environment::getEnv($envKey);
         if ($env) {
-            $addresses = array_merge($addresses, self::convertConfigToAddreses($env));
+            $addresses = array_merge($addresses, Email::convertConfigToAddreses($env));
         }
         return $addresses;
     }
@@ -403,7 +403,7 @@ public function getHTMLTemplate(): string
         }
 
         return ThemeResourceLoader::inst()->findTemplate(
-            SSViewer::get_templates_by_class(static::class, '', self::class),
+            SSViewer::get_templates_by_class(static::class, '', Email::class),
             SSViewer::get_themes()
         );
     }
diff --git a/src/Control/HTTP.php b/src/Control/HTTP.php
index d13bd7728be..d8a3b7248c9 100644
--- a/src/Control/HTTP.php
+++ b/src/Control/HTTP.php
@@ -226,7 +226,7 @@ public static function setGetVar($varname, $varvalue, $currentURL = null, $separ
      */
     public static function RAW_setGetVar($varname, $varvalue, $currentURL = null)
     {
-        $url = self::setGetVar($varname, $varvalue, $currentURL);
+        $url = HTTP::setGetVar($varname, $varvalue, $currentURL);
         return Convert::xml2raw($url);
     }
 
@@ -268,7 +268,7 @@ public static function findByTagAndAttribute($content, $attributes)
      */
     public static function getLinksIn($content)
     {
-        return self::findByTagAndAttribute($content, ["a" => "href"]);
+        return HTTP::findByTagAndAttribute($content, ["a" => "href"]);
     }
 
     /**
@@ -278,7 +278,7 @@ public static function getLinksIn($content)
      */
     public static function getImagesIn($content)
     {
-        return self::findByTagAndAttribute($content, ["img" => "src"]);
+        return HTTP::findByTagAndAttribute($content, ["img" => "src"]);
     }
 
     /**
diff --git a/src/Control/HTTPRequest.php b/src/Control/HTTPRequest.php
index 8cc1ab9152a..ee014d0fdb0 100644
--- a/src/Control/HTTPRequest.php
+++ b/src/Control/HTTPRequest.php
@@ -850,7 +850,7 @@ public function httpMethod()
      */
     public function setHttpMethod($method)
     {
-        if (!self::isValidHttpMethod($method)) {
+        if (!HTTPRequest::isValidHttpMethod($method)) {
             throw new \InvalidArgumentException('HTTPRequest::setHttpMethod: Invalid HTTP method');
         }
 
diff --git a/src/Control/HTTPResponse.php b/src/Control/HTTPResponse.php
index b7e47cbbe67..3cb4a498bbc 100644
--- a/src/Control/HTTPResponse.php
+++ b/src/Control/HTTPResponse.php
@@ -174,7 +174,7 @@ public function setProtocolVersion($protocolVersion)
      */
     public function setStatusCode($code, $description = null)
     {
-        if (isset(self::$status_codes[$code])) {
+        if (isset(HTTPResponse::$status_codes[$code])) {
             $this->statusCode = $code;
         } else {
             throw new InvalidArgumentException("Unrecognised HTTP status code '$code'");
@@ -183,7 +183,7 @@ public function setStatusCode($code, $description = null)
         if ($description) {
             $this->statusDescription = $description;
         } else {
-            $this->statusDescription = self::$status_codes[$code];
+            $this->statusDescription = HTTPResponse::$status_codes[$code];
         }
         return $this;
     }
@@ -320,7 +320,7 @@ private function sanitiseHeader(string $value): string
 
     public function redirect(string $dest, int $code = 302): static
     {
-        if (!in_array($code, self::$redirect_codes)) {
+        if (!in_array($code, HTTPResponse::$redirect_codes)) {
             trigger_error("Invalid HTTP redirect code {$code}", E_USER_WARNING);
             $code = 302;
         }
@@ -439,7 +439,7 @@ public function isFinished()
      */
     public function isRedirect()
     {
-        return in_array($this->getStatusCode(), self::$redirect_codes);
+        return in_array($this->getStatusCode(), HTTPResponse::$redirect_codes);
     }
 
     /**
diff --git a/src/Control/Middleware/HTTPCacheControlMiddleware.php b/src/Control/Middleware/HTTPCacheControlMiddleware.php
index 94fb0e2c3b3..c3da4f756c9 100644
--- a/src/Control/Middleware/HTTPCacheControlMiddleware.php
+++ b/src/Control/Middleware/HTTPCacheControlMiddleware.php
@@ -68,20 +68,20 @@ public function process(HTTPRequest $request, callable $delegate)
      * @var array
      */
     protected $stateDirectives = [
-        self::STATE_DISABLED => [
+        HTTPCacheControlMiddleware::STATE_DISABLED => [
             'no-cache' => true,
             'no-store' => true,
             'must-revalidate' => true,
         ],
-        self::STATE_PRIVATE => [
+        HTTPCacheControlMiddleware::STATE_PRIVATE => [
             'private' => true,
             'must-revalidate' => true,
         ],
-        self::STATE_PUBLIC => [
+        HTTPCacheControlMiddleware::STATE_PUBLIC => [
             'public' => true,
             'must-revalidate' => true,
         ],
-        self::STATE_ENABLED => [
+        HTTPCacheControlMiddleware::STATE_ENABLED => [
             'no-cache' => true,
             'must-revalidate' => true,
         ]
@@ -93,7 +93,7 @@ public function process(HTTPRequest $request, callable $delegate)
      * @config
      * @var string
      */
-    private static $defaultState = self::STATE_ENABLED;
+    private static $defaultState = HTTPCacheControlMiddleware::STATE_ENABLED;
 
     /**
      * Current state
@@ -307,7 +307,7 @@ public function getState()
      */
     protected function applyChangeLevel($level, $force)
     {
-        $forcingLevel = $level + ($force ? self::LEVEL_FORCED : 0);
+        $forcingLevel = $level + ($force ? HTTPCacheControlMiddleware::LEVEL_FORCED : 0);
         if ($forcingLevel < $this->getForcingLevel()) {
             return false;
         }
@@ -465,7 +465,7 @@ public function getDirectives()
     public function setNoStore($noStore = true)
     {
         // Affect all non-disabled states
-        $applyTo = [self::STATE_ENABLED, self::STATE_PRIVATE, self::STATE_PUBLIC];
+        $applyTo = [HTTPCacheControlMiddleware::STATE_ENABLED, HTTPCacheControlMiddleware::STATE_PRIVATE, HTTPCacheControlMiddleware::STATE_PUBLIC];
         if ($noStore) {
             $this->setStateDirective($applyTo, 'no-store');
             $this->removeStateDirective($applyTo, 'max-age');
@@ -486,7 +486,7 @@ public function setNoStore($noStore = true)
     public function setNoCache($noCache = true)
     {
         // Affect all non-disabled states
-        $applyTo = [self::STATE_ENABLED, self::STATE_PRIVATE, self::STATE_PUBLIC];
+        $applyTo = [HTTPCacheControlMiddleware::STATE_ENABLED, HTTPCacheControlMiddleware::STATE_PRIVATE, HTTPCacheControlMiddleware::STATE_PUBLIC];
         if ($noCache) {
             $this->setStateDirective($applyTo, 'no-cache');
             $this->removeStateDirective($applyTo, 'max-age');
@@ -509,7 +509,7 @@ public function setNoCache($noCache = true)
     public function setMaxAge($age)
     {
         // Affect all non-disabled states
-        $applyTo = [self::STATE_ENABLED, self::STATE_PRIVATE, self::STATE_PUBLIC];
+        $applyTo = [HTTPCacheControlMiddleware::STATE_ENABLED, HTTPCacheControlMiddleware::STATE_PRIVATE, HTTPCacheControlMiddleware::STATE_PUBLIC];
         $this->setStateDirective($applyTo, 'max-age', $age);
         if ($age) {
             $this->removeStateDirective($applyTo, 'no-cache');
@@ -529,7 +529,7 @@ public function setMaxAge($age)
     public function setSharedMaxAge($age)
     {
         // Affect all non-disabled states
-        $applyTo = [self::STATE_ENABLED, self::STATE_PRIVATE, self::STATE_PUBLIC];
+        $applyTo = [HTTPCacheControlMiddleware::STATE_ENABLED, HTTPCacheControlMiddleware::STATE_PRIVATE, HTTPCacheControlMiddleware::STATE_PUBLIC];
         $this->setStateDirective($applyTo, 's-maxage', $age);
         if ($age) {
             $this->removeStateDirective($applyTo, 'no-cache');
@@ -547,7 +547,7 @@ public function setSharedMaxAge($age)
      */
     public function setMustRevalidate($mustRevalidate = true)
     {
-        $applyTo = [self::STATE_ENABLED, self::STATE_PRIVATE, self::STATE_PUBLIC];
+        $applyTo = [HTTPCacheControlMiddleware::STATE_ENABLED, HTTPCacheControlMiddleware::STATE_PRIVATE, HTTPCacheControlMiddleware::STATE_PUBLIC];
         $this->setStateDirective($applyTo, 'must-revalidate', $mustRevalidate);
         return $this;
     }
@@ -569,8 +569,8 @@ public function setMustRevalidate($mustRevalidate = true)
     public function enableCache($force = false, $maxAge = null)
     {
         // Only execute this if its forcing level is high enough
-        if ($this->applyChangeLevel(self::LEVEL_ENABLED, $force)) {
-            $this->setState(self::STATE_ENABLED);
+        if ($this->applyChangeLevel(HTTPCacheControlMiddleware::LEVEL_ENABLED, $force)) {
+            $this->setState(HTTPCacheControlMiddleware::STATE_ENABLED);
         }
 
         if (!is_null($maxAge)) {
@@ -600,8 +600,8 @@ public function enableCache($force = false, $maxAge = null)
     public function disableCache($force = false)
     {
         // Only execute this if its forcing level is high enough
-        if ($this->applyChangeLevel(self::LEVEL_DISABLED, $force)) {
-            $this->setState(self::STATE_DISABLED);
+        if ($this->applyChangeLevel(HTTPCacheControlMiddleware::LEVEL_DISABLED, $force)) {
+            $this->setState(HTTPCacheControlMiddleware::STATE_DISABLED);
         }
         return $this;
     }
@@ -620,8 +620,8 @@ public function disableCache($force = false)
     public function privateCache($force = false)
     {
         // Only execute this if its forcing level is high enough
-        if ($this->applyChangeLevel(self::LEVEL_PRIVATE, $force)) {
-            $this->setState(self::STATE_PRIVATE);
+        if ($this->applyChangeLevel(HTTPCacheControlMiddleware::LEVEL_PRIVATE, $force)) {
+            $this->setState(HTTPCacheControlMiddleware::STATE_PRIVATE);
         }
         return $this;
     }
@@ -641,8 +641,8 @@ public function privateCache($force = false)
     public function publicCache($force = false, $maxAge = null)
     {
         // Only execute this if its forcing level is high enough
-        if ($this->applyChangeLevel(self::LEVEL_PUBLIC, $force)) {
-            $this->setState(self::STATE_PUBLIC);
+        if ($this->applyChangeLevel(HTTPCacheControlMiddleware::LEVEL_PUBLIC, $force)) {
+            $this->setState(HTTPCacheControlMiddleware::STATE_PUBLIC);
         }
 
         if (!is_null($maxAge)) {
diff --git a/src/Control/RequestHandler.php b/src/Control/RequestHandler.php
index 872c6a05bae..fa2d02af0b2 100644
--- a/src/Control/RequestHandler.php
+++ b/src/Control/RequestHandler.php
@@ -130,7 +130,7 @@ public function __construct()
     /**
      * Handles URL requests.
      *
-     *  - ViewableData::handleRequest() iterates through each rule in {@link self::$url_handlers}.
+     *  - ViewableData::handleRequest() iterates through each rule in {@link RequestHandler::$url_handlers}.
      *  - If the rule matches, the named method will be called.
      *  - If there is still more URL to be processed, then handleRequest()
      *    is called on the object that that method returns.
@@ -445,7 +445,7 @@ protected function definingClassForAction($actionOrigCasing)
 
     /**
      * Check that the given action is allowed to be called from a URL.
-     * It will interrogate {@link self::$allowed_actions} to determine this.
+     * It will interrogate {@link RequestHandler::$allowed_actions} to determine this.
      *
      * @param string $action
      * @return bool
diff --git a/src/Control/Session.php b/src/Control/Session.php
index 8bdf6e0e99a..881a480a4cc 100644
--- a/src/Control/Session.php
+++ b/src/Control/Session.php
@@ -235,7 +235,7 @@ public function init(HTTPRequest $request)
         }
 
         // Funny business detected!
-        if (self::config()->get('strict_user_agent_check') && isset($this->data['HTTP_USER_AGENT'])) {
+        if (Session::config()->get('strict_user_agent_check') && isset($this->data['HTTP_USER_AGENT'])) {
             if ($this->data['HTTP_USER_AGENT'] !== $this->userAgent($request)) {
                 $this->clearAll();
                 $this->restart($request);
diff --git a/src/Control/Util/IPUtils.php b/src/Control/Util/IPUtils.php
index 0d8d4e57c82..be3cdc52257 100644
--- a/src/Control/Util/IPUtils.php
+++ b/src/Control/Util/IPUtils.php
@@ -44,7 +44,7 @@ public static function checkIP($requestIP, $ips)
         $method = substr_count($requestIP ?? '', ':') > 1 ? 'checkIP6' : 'checkIP4';
 
         foreach ($ips as $ip) {
-            if (self::$method($requestIP, trim($ip ?? ''))) {
+            if (IPUtils::$method($requestIP, trim($ip ?? ''))) {
                 return true;
             }
         }
diff --git a/src/Core/BaseKernel.php b/src/Core/BaseKernel.php
index 4e6c56a1c90..957aa01cf13 100644
--- a/src/Core/BaseKernel.php
+++ b/src/Core/BaseKernel.php
@@ -139,7 +139,7 @@ public function __construct($basePath)
      */
     protected function bootPHP()
     {
-        if ($this->getEnvironment() === self::LIVE) {
+        if ($this->getEnvironment() === BaseKernel::LIVE) {
             // limited to fatal errors and warnings in live mode
             error_reporting(E_ALL & ~(E_DEPRECATED | E_STRICT | E_NOTICE));
         } else {
@@ -262,7 +262,7 @@ public function getEnvironment()
             return $env;
         }
 
-        return self::LIVE;
+        return BaseKernel::LIVE;
     }
 
     abstract public function boot($flush = false);
@@ -427,7 +427,7 @@ public function setModuleLoader(ModuleLoader $moduleLoader)
 
     public function setEnvironment($environment)
     {
-        if (!in_array($environment, [self::DEV, self::TEST, self::LIVE, null])) {
+        if (!in_array($environment, [BaseKernel::DEV, BaseKernel::TEST, BaseKernel::LIVE, null])) {
             throw new InvalidArgumentException(
                 "Director::set_environment_type passed '$environment'.  It should be passed dev, test, or live"
             );
diff --git a/src/Core/ClassInfo.php b/src/Core/ClassInfo.php
index 7c8094d0f0e..527af52386a 100644
--- a/src/Core/ClassInfo.php
+++ b/src/Core/ClassInfo.php
@@ -88,16 +88,16 @@ public static function exists($class)
     public static function hasTable($tableName)
     {
         // Cache the list of all table names to reduce on DB traffic
-        if (empty(self::$_cache_all_tables) && DB::is_active()) {
-            self::$_cache_all_tables = DB::get_schema()->tableList();
+        if (empty(ClassInfo::$_cache_all_tables) && DB::is_active()) {
+            ClassInfo::$_cache_all_tables = DB::get_schema()->tableList();
         }
-        return !empty(self::$_cache_all_tables[strtolower($tableName)]);
+        return !empty(ClassInfo::$_cache_all_tables[strtolower($tableName)]);
     }
 
     public static function reset_db_cache()
     {
-        self::$_cache_all_tables = null;
-        self::$_cache_ancestry = [];
+        ClassInfo::$_cache_all_tables = null;
+        ClassInfo::$_cache_ancestry = [];
     }
 
     /**
@@ -114,7 +114,7 @@ public static function getValidSubClasses($class = SiteTree::class, $includeUnba
             return [];
         }
 
-        $class = self::class_name($class);
+        $class = ClassInfo::class_name($class);
         if ($includeUnbacked) {
             $table = DataObject::getSchema()->tableName($class);
             $classes = DB::get_schema()->enumValuesForField($table, 'ClassName');
@@ -138,10 +138,10 @@ public static function dataClassesFor($nameOrObject)
         }
 
         // Get all classes
-        $class = self::class_name($nameOrObject);
+        $class = ClassInfo::class_name($nameOrObject);
         $classes = array_merge(
-            self::ancestry($class),
-            self::subclassesFor($class)
+            ClassInfo::ancestry($class),
+            ClassInfo::subclassesFor($class)
         );
 
         // Filter by table
@@ -178,7 +178,7 @@ public static function subclassesFor($nameOrObject, $includeBaseClass = true)
         }
 
         // Get class names
-        $className = self::class_name($nameOrObject);
+        $className = ClassInfo::class_name($nameOrObject);
         $lowerClassName = strtolower($className ?? '');
 
         // Merge with descendants
@@ -192,7 +192,7 @@ public static function subclassesFor($nameOrObject, $includeBaseClass = true)
     /**
      * Convert a class name in any case and return it as it was defined in PHP
      *
-     * eg: self::class_name('dataobJEct'); //returns 'DataObject'
+     * eg: ClassInfo::class_name('dataobJEct'); //returns 'DataObject'
      *
      * @param string|object $nameOrObject The classname or object you want to normalise
      * @throws \ReflectionException
@@ -234,23 +234,23 @@ public static function ancestry($nameOrObject, $tablesOnly = false)
             return [];
         }
 
-        $class = self::class_name($nameOrObject);
+        $class = ClassInfo::class_name($nameOrObject);
 
         $lowerClass = strtolower($class ?? '');
 
         $cacheKey = $lowerClass . '_' . (string)$tablesOnly;
         $parent = $class;
-        if (!isset(self::$_cache_ancestry[$cacheKey])) {
+        if (!isset(ClassInfo::$_cache_ancestry[$cacheKey])) {
             $ancestry = [];
             do {
                 if (!$tablesOnly || DataObject::getSchema()->classHasTable($parent)) {
                     $ancestry[strtolower($parent)] = $parent;
                 }
             } while ($parent = get_parent_class($parent ?? ''));
-            self::$_cache_ancestry[$cacheKey] = array_reverse($ancestry ?? []);
+            ClassInfo::$_cache_ancestry[$cacheKey] = array_reverse($ancestry ?? []);
         }
 
-        return self::$_cache_ancestry[$cacheKey];
+        return ClassInfo::$_cache_ancestry[$cacheKey];
     }
 
     /**
@@ -273,7 +273,7 @@ public static function implementorsOf($interfaceName)
     public static function classImplements($className, $interfaceName)
     {
         $lowerClassName = strtolower($className ?? '');
-        $implementors = self::implementorsOf($interfaceName);
+        $implementors = ClassInfo::implementorsOf($interfaceName);
         return isset($implementors[$lowerClassName]);
     }
 
@@ -336,22 +336,22 @@ public static function has_method_from($class, $method, $compclass)
         $lClass = strtolower($class ?? '');
         $lMethod = strtolower($method ?? '');
         $lCompclass = strtolower($compclass ?? '');
-        if (!isset(self::$_cache_methods[$lClass])) {
-            self::$_cache_methods[$lClass] = [];
+        if (!isset(ClassInfo::$_cache_methods[$lClass])) {
+            ClassInfo::$_cache_methods[$lClass] = [];
         }
 
-        if (!array_key_exists($lMethod, self::$_cache_methods[$lClass] ?? [])) {
-            self::$_cache_methods[$lClass][$lMethod] = false;
+        if (!array_key_exists($lMethod, ClassInfo::$_cache_methods[$lClass] ?? [])) {
+            ClassInfo::$_cache_methods[$lClass][$lMethod] = false;
 
             $classRef = new ReflectionClass($class);
 
             if ($classRef->hasMethod($method)) {
                 $methodRef = $classRef->getMethod($method);
-                self::$_cache_methods[$lClass][$lMethod] = $methodRef->getDeclaringClass()->getName();
+                ClassInfo::$_cache_methods[$lClass][$lMethod] = $methodRef->getDeclaringClass()->getName();
             }
         }
 
-        return strtolower(self::$_cache_methods[$lClass][$lMethod] ?? '') === $lCompclass;
+        return strtolower(ClassInfo::$_cache_methods[$lClass][$lMethod] ?? '') === $lCompclass;
     }
 
     /**
@@ -561,7 +561,7 @@ public static function classesWithExtension(
         bool $includeBaseClass = false
     ): array {
         // get class names
-        $baseClass = self::class_name($baseClassOrObject);
+        $baseClass = ClassInfo::class_name($baseClassOrObject);
 
         // get a list of all subclasses for a given class
         $classes = ClassInfo::subclassesFor($baseClass, $includeBaseClass);
diff --git a/src/Core/Config/Config.php b/src/Core/Config/Config.php
index 89aab2a32d2..2981b7c3d55 100644
--- a/src/Core/Config/Config.php
+++ b/src/Core/Config/Config.php
@@ -79,7 +79,7 @@ public static function modify()
     public static function nest()
     {
         // Clone current config and nest
-        $new = self::inst()->nest();
+        $new = Config::inst()->nest();
         ConfigLoader::inst()->pushManifest($new);
         return $new;
     }
diff --git a/src/Core/Config/ConfigLoader.php b/src/Core/Config/ConfigLoader.php
index 9ea7104e41c..9af5a452367 100644
--- a/src/Core/Config/ConfigLoader.php
+++ b/src/Core/Config/ConfigLoader.php
@@ -12,7 +12,7 @@ class ConfigLoader
 {
     /**
      * @internal
-     * @var self
+     * @var ConfigLoader
      */
     private static $instance;
 
@@ -22,11 +22,11 @@ class ConfigLoader
     protected $manifests = [];
 
     /**
-     * @return self
+     * @return ConfigLoader
      */
     public static function inst()
     {
-        return self::$instance ? self::$instance : self::$instance = new static();
+        return ConfigLoader::$instance ? ConfigLoader::$instance : ConfigLoader::$instance = new static();
     }
 
     /**
@@ -37,7 +37,7 @@ public static function inst()
      */
     public function getManifest()
     {
-        if ($this !== self::$instance) {
+        if ($this !== ConfigLoader::$instance) {
             throw new BadMethodCallException(
                 "Non-current config manifest cannot be accessed. Please call ->activate() first"
             );
diff --git a/src/Core/Convert.php b/src/Core/Convert.php
index c4140ad863c..c7fbeed4503 100644
--- a/src/Core/Convert.php
+++ b/src/Core/Convert.php
@@ -36,7 +36,7 @@ class Convert
      */
     public static function raw2att($val)
     {
-        return self::raw2xml($val);
+        return Convert::raw2xml($val);
     }
 
     /**
@@ -49,7 +49,7 @@ public static function raw2att($val)
      */
     public static function raw2htmlatt($val)
     {
-        return self::raw2att($val);
+        return Convert::raw2att($val);
     }
 
     /**
@@ -68,13 +68,13 @@ public static function raw2htmlname($val)
     {
         if (is_array($val)) {
             foreach ($val as $k => $v) {
-                $val[$k] = self::raw2htmlname($v);
+                $val[$k] = Convert::raw2htmlname($v);
             }
 
             return $val;
         }
 
-        return self::raw2att($val);
+        return Convert::raw2att($val);
     }
 
     /**
@@ -93,7 +93,7 @@ public static function raw2htmlid($val)
     {
         if (is_array($val)) {
             foreach ($val as $k => $v) {
-                $val[$k] = self::raw2htmlid($v);
+                $val[$k] = Convert::raw2htmlid($v);
             }
 
             return $val;
@@ -122,7 +122,7 @@ public static function raw2xml($val)
     {
         if (is_array($val)) {
             foreach ($val as $k => $v) {
-                $val[$k] = self::raw2xml($v);
+                $val[$k] = Convert::raw2xml($v);
             }
             return $val;
         }
@@ -142,7 +142,7 @@ public static function raw2js($val)
     {
         if (is_array($val)) {
             foreach ($val as $k => $v) {
-                $val[$k] = self::raw2js($v);
+                $val[$k] = Convert::raw2js($v);
             }
             return $val;
         }
@@ -171,7 +171,7 @@ public static function raw2sql($val, $quoted = false)
     {
         if (is_array($val)) {
             foreach ($val as $k => $v) {
-                $val[$k] = self::raw2sql($v, $quoted);
+                $val[$k] = Convert::raw2sql($v, $quoted);
             }
             return $val;
         }
@@ -211,14 +211,14 @@ public static function xml2raw($val)
     {
         if (is_array($val)) {
             foreach ($val as $k => $v) {
-                $val[$k] = self::xml2raw($v);
+                $val[$k] = Convert::xml2raw($v);
             }
             return $val;
         }
 
         // More complex text needs to use html2raw instead
         if (strpos($val ?? '', '<') !== false) {
-            return self::html2raw($val);
+            return Convert::html2raw($val);
         }
 
         return html_entity_decode($val ?? '', ENT_QUOTES, 'UTF-8');
diff --git a/src/Core/Environment.php b/src/Core/Environment.php
index a6b0fc7ef56..1e328647d22 100644
--- a/src/Core/Environment.php
+++ b/src/Core/Environment.php
@@ -217,7 +217,7 @@ public static function putEnv($string)
         // Parse name-value pairs
         $envVars = parse_ini_string($string ?? '') ?: [];
         foreach ($envVars as $name => $value) {
-            self::setEnv($name, $value);
+            Environment::setEnv($name, $value);
         }
     }
 
diff --git a/src/Core/Extensible.php b/src/Core/Extensible.php
index 91bf23ce2a9..7ec91ee4ebc 100644
--- a/src/Core/Extensible.php
+++ b/src/Core/Extensible.php
@@ -124,7 +124,7 @@ protected function defineExtensionMethods()
         foreach ($extensions as $extensionClass => $extensionInstance) {
             foreach ($this->findMethodsFrom($extensionInstance) as $method) {
                 $this->addCallbackMethod($method, function ($inst, $args) use ($method, $extensionClass) {
-                    /** @var Extensible $inst */
+                    /** @var self $inst */
                     $extension = $inst->getExtensionInstance($extensionClass);
                     if (!$extension) {
                         return null;
diff --git a/src/Core/Injector/Injector.php b/src/Core/Injector/Injector.php
index 7af9df4c240..afb909a5b84 100644
--- a/src/Core/Injector/Injector.php
+++ b/src/Core/Injector/Injector.php
@@ -262,7 +262,7 @@ public static function inst()
     public static function nest()
     {
         // Clone current injector and nest
-        $new = clone self::inst();
+        $new = clone Injector::inst();
         InjectorLoader::inst()->pushManifest($new);
         return $new;
     }
@@ -597,7 +597,7 @@ protected function instantiate($spec, $id = null, $type = null)
 
         // If we're dealing with a DataObject singleton without specific constructor params, pass through Singleton
         // flag as second argument
-        if ((!$type || $type !== self::PROTOTYPE)
+        if ((!$type || $type !== Injector::PROTOTYPE)
             && empty($constructorParams)
             && is_subclass_of($class, DataObject::class)) {
             $constructorParams = [null, DataObject::CREATE_SINGLETON];
@@ -651,7 +651,7 @@ protected function instantiate($spec, $id = null, $type = null)
             $type = isset($spec['type']) ? $spec['type'] : null;
         }
 
-        if ($id && (!$type || $type !== self::PROTOTYPE)) {
+        if ($id && (!$type || $type !== Injector::PROTOTYPE)) {
             // this ABSOLUTELY must be set before the object is injected.
             // This prevents circular reference errors down the line
             $this->serviceCache[$id] = $object;
@@ -1006,16 +1006,16 @@ protected function getNamedService($name, $asSingleton = true, $constructorArgs
 
         // Check if we are getting a prototype or singleton
         $type = $asSingleton
-            ? (isset($spec['type']) ? $spec['type'] : self::SINGLETON)
-            : self::PROTOTYPE;
+            ? (isset($spec['type']) ? $spec['type'] : Injector::SINGLETON)
+            : Injector::PROTOTYPE;
 
         // Return existing instance for singletons
-        if ($type === self::SINGLETON && isset($this->serviceCache[$name])) {
+        if ($type === Injector::SINGLETON && isset($this->serviceCache[$name])) {
             return $this->serviceCache[$name];
         }
 
         // Update constructor args
-        if ($type === self::PROTOTYPE && $constructorArgs) {
+        if ($type === Injector::PROTOTYPE && $constructorArgs) {
             // Passed in args are expected to already be normalised (no service references)
             $spec['constructor'] = $constructorArgs;
         } else {
diff --git a/src/Core/Injector/InjectorLoader.php b/src/Core/Injector/InjectorLoader.php
index 4b5a857a5a6..6a1e958ef37 100644
--- a/src/Core/Injector/InjectorLoader.php
+++ b/src/Core/Injector/InjectorLoader.php
@@ -13,7 +13,7 @@ class InjectorLoader
 
     /**
      * @internal
-     * @var self
+     * @var InjectorLoader
      */
     private static $instance;
 
@@ -23,11 +23,11 @@ class InjectorLoader
     protected $manifests = [];
 
     /**
-     * @return self
+     * @return InjectorLoader
      */
     public static function inst()
     {
-        return self::$instance ? self::$instance : self::$instance = new static();
+        return InjectorLoader::$instance ? InjectorLoader::$instance : InjectorLoader::$instance = new static();
     }
 
     /**
@@ -38,13 +38,13 @@ public static function inst()
      */
     public function getManifest()
     {
-        if ($this !== self::$instance) {
+        if ($this !== InjectorLoader::$instance) {
             throw new BadMethodCallException(
                 "Non-current injector manifest cannot be accessed. Please call ->activate() first"
             );
         }
         if (empty($this->manifests)) {
-            throw new BadMethodCallException(self::NO_MANIFESTS_AVAILABLE);
+            throw new BadMethodCallException(InjectorLoader::NO_MANIFESTS_AVAILABLE);
         }
         return $this->manifests[count($this->manifests) - 1];
     }
diff --git a/src/Core/Manifest/ClassLoader.php b/src/Core/Manifest/ClassLoader.php
index d8386c5e431..6ce5d65b685 100644
--- a/src/Core/Manifest/ClassLoader.php
+++ b/src/Core/Manifest/ClassLoader.php
@@ -27,7 +27,7 @@ class ClassLoader
      */
     public static function inst()
     {
-        return self::$instance ? self::$instance : self::$instance = new static();
+        return ClassLoader::$instance ? ClassLoader::$instance : ClassLoader::$instance = new static();
     }
 
     /**
diff --git a/src/Core/Manifest/ManifestFileFinder.php b/src/Core/Manifest/ManifestFileFinder.php
index 493d911752a..f2a110db53e 100644
--- a/src/Core/Manifest/ManifestFileFinder.php
+++ b/src/Core/Manifest/ManifestFileFinder.php
@@ -41,7 +41,7 @@ public function acceptDir($basename, $pathname, $depth)
         $inVendor = $this->isInsideVendor($basename, $pathname, $depth);
         if ($inVendor) {
             // Skip nested vendor folders (e.g. vendor/silverstripe/framework/vendor)
-            if ($depth == 4 && basename($pathname ?? '') === self::VENDOR_DIR) {
+            if ($depth == 4 && basename($pathname ?? '') === ManifestFileFinder::VENDOR_DIR) {
                 return false;
             }
 
@@ -82,7 +82,7 @@ public function acceptDir($basename, $pathname, $depth)
     public function isInsideVendor($basename, $pathname, $depth)
     {
         $base = basename($this->upLevels($pathname, $depth - 1) ?? '');
-        return $base === self::VENDOR_DIR;
+        return $base === ManifestFileFinder::VENDOR_DIR;
     }
 
     /**
@@ -170,12 +170,12 @@ public function isDirectoryModule($basename, $pathname, $depth)
         }
 
         // True if config file exists
-        if (file_exists($pathname . '/' . self::CONFIG_FILE)) {
+        if (file_exists($pathname . '/' . ManifestFileFinder::CONFIG_FILE)) {
             return true;
         }
 
         // True if config dir exists
-        if (file_exists($pathname . '/' . self::CONFIG_DIR)) {
+        if (file_exists($pathname . '/' . ManifestFileFinder::CONFIG_DIR)) {
             return true;
         }
 
@@ -207,9 +207,9 @@ protected function upLevels($pathname, $depth)
      */
     protected function getIgnoredDirs()
     {
-        $ignored = [self::LANG_DIR, 'node_modules'];
+        $ignored = [ManifestFileFinder::LANG_DIR, 'node_modules'];
         if ($this->getOption('ignore_tests')) {
-            $ignored[] = self::TESTS_DIR;
+            $ignored[] = ManifestFileFinder::TESTS_DIR;
         }
         return $ignored;
     }
@@ -229,7 +229,7 @@ public function isDirectoryIgnored($basename, $pathname, $depth)
         }
 
         // Check if manifest-ignored is present
-        if (file_exists($pathname . '/' . self::EXCLUDE_FILE)) {
+        if (file_exists($pathname . '/' . ManifestFileFinder::EXCLUDE_FILE)) {
             return true;
         }
 
diff --git a/src/Core/Manifest/ModuleLoader.php b/src/Core/Manifest/ModuleLoader.php
index 10dbe948b8b..8e1c59bd78e 100644
--- a/src/Core/Manifest/ModuleLoader.php
+++ b/src/Core/Manifest/ModuleLoader.php
@@ -8,7 +8,7 @@
 class ModuleLoader
 {
     /**
-     * @var self
+     * @var ModuleLoader
      */
     private static $instance;
 
@@ -18,11 +18,11 @@ class ModuleLoader
     protected $manifests = [];
 
     /**
-     * @return self
+     * @return ModuleLoader
      */
     public static function inst()
     {
-        return self::$instance ? self::$instance : self::$instance = new static();
+        return ModuleLoader::$instance ? ModuleLoader::$instance : ModuleLoader::$instance = new static();
     }
 
     /**
diff --git a/src/Core/Manifest/ModuleManifest.php b/src/Core/Manifest/ModuleManifest.php
index 1ec7eaedfe0..bb8f29a50bd 100644
--- a/src/Core/Manifest/ModuleManifest.php
+++ b/src/Core/Manifest/ModuleManifest.php
@@ -241,7 +241,7 @@ public function sort()
         );
 
         if ($project) {
-            $sorter->setVariable(self::PROJECT_KEY, $project);
+            $sorter->setVariable(ModuleManifest::PROJECT_KEY, $project);
         }
 
         $this->modules = $sorter->getSortedList();
diff --git a/src/Core/Manifest/VersionProvider.php b/src/Core/Manifest/VersionProvider.php
index 4a0d4b48e44..b3477a3ba05 100644
--- a/src/Core/Manifest/VersionProvider.php
+++ b/src/Core/Manifest/VersionProvider.php
@@ -175,7 +175,7 @@ private function filterModules(array $modules)
      */
     public function getModules()
     {
-        $modules = Config::inst()->get(self::class, 'modules');
+        $modules = Config::inst()->get(VersionProvider::class, 'modules');
         return !empty($modules) ? $modules : ['silverstripe/framework' => 'Framework'];
     }
 
diff --git a/src/Core/Path.php b/src/Core/Path.php
index 891dc3754ce..7d06a1e8516 100644
--- a/src/Core/Path.php
+++ b/src/Core/Path.php
@@ -53,9 +53,9 @@ public static function normalise($path, $relative = false)
     {
         $path = trim(Convert::slashes($path) ?? '');
         if ($relative) {
-            return trim($path ?? '', self::TRIM_CHARS ?? '');
+            return trim($path ?? '', Path::TRIM_CHARS ?? '');
         } else {
-            return rtrim($path ?? '', self::TRIM_CHARS ?? '');
+            return rtrim($path ?? '', Path::TRIM_CHARS ?? '');
         }
     }
 }
diff --git a/src/Dev/Backtrace.php b/src/Dev/Backtrace.php
index bef017108da..62d402efc51 100644
--- a/src/Dev/Backtrace.php
+++ b/src/Dev/Backtrace.php
@@ -31,7 +31,7 @@ class Backtrace
      */
     public static function filtered_backtrace($ignoredFunctions = null)
     {
-        return self::filter_backtrace(debug_backtrace(), $ignoredFunctions);
+        return Backtrace::filter_backtrace(debug_backtrace(), $ignoredFunctions);
     }
 
     /**
@@ -70,7 +70,7 @@ public static function filter_backtrace($bt, $ignoredFunctions = null)
             }
         }
 
-        while ($bt && in_array(self::full_func_name($bt[0]), $defaultIgnoredFunctions ?? [])) {
+        while ($bt && in_array(Backtrace::full_func_name($bt[0]), $defaultIgnoredFunctions ?? [])) {
             array_shift($bt);
         }
 
@@ -82,7 +82,7 @@ public static function filter_backtrace($bt, $ignoredFunctions = null)
             if (!empty($frame['class'])) {
                 foreach ($ignoredArgs as $fnSpec) {
                     if (is_array($fnSpec)
-                        && self::matchesFilterableClass($frame['class'], $fnSpec[0])
+                        && Backtrace::matchesFilterableClass($frame['class'], $fnSpec[0])
                         && $frame['function'] == $fnSpec[1]
                     ) {
                         $match = true;
@@ -115,7 +115,7 @@ public static function filter_backtrace($bt, $ignoredFunctions = null)
     public static function backtrace($returnVal = false, $ignoreAjax = false, $ignoredFunctions = null)
     {
         $plainText = Director::is_cli() || (Director::is_ajax() && !$ignoreAjax);
-        $result = self::get_rendered_backtrace(debug_backtrace(), $plainText, $ignoredFunctions);
+        $result = Backtrace::get_rendered_backtrace(debug_backtrace(), $plainText, $ignoredFunctions);
         if ($returnVal) {
             return $result;
         } else {
@@ -176,11 +176,11 @@ public static function get_rendered_backtrace($bt, $plainText = false, $ignoredF
         if (empty($bt)) {
             return '';
         }
-        $bt = self::filter_backtrace($bt, $ignoredFunctions);
+        $bt = Backtrace::filter_backtrace($bt, $ignoredFunctions);
         $result = ($plainText) ? '' : '<ul>';
         foreach ($bt as $item) {
             if ($plainText) {
-                $result .= self::full_func_name($item, true) . "\n";
+                $result .= Backtrace::full_func_name($item, true) . "\n";
                 if (isset($item['line']) && isset($item['file'])) {
                     $result .= basename($item['file'] ?? '') . ":$item[line]\n";
                 }
@@ -189,7 +189,7 @@ public static function get_rendered_backtrace($bt, $plainText = false, $ignoredF
                 if ($item['function'] == 'user_error') {
                     $name = $item['args'][0];
                 } else {
-                    $name = self::full_func_name($item, true);
+                    $name = Backtrace::full_func_name($item, true);
                 }
                 $result .= "<li><b>" . htmlentities($name ?? '', ENT_COMPAT, 'UTF-8') . "</b>\n<br />\n";
                 $result .=  isset($item['file']) ? htmlentities(basename($item['file']), ENT_COMPAT, 'UTF-8') : '';
diff --git a/src/Dev/BulkLoader.php b/src/Dev/BulkLoader.php
index 69cd993d433..51538760350 100644
--- a/src/Dev/BulkLoader.php
+++ b/src/Dev/BulkLoader.php
@@ -23,7 +23,7 @@ abstract class BulkLoader extends ViewableData
     /**
      * Each row in the imported dataset should map to one instance
      * of this class (with optional property translation
-     * through {@self::$columnMaps}.
+     * through {@BulkLoader::$columnMaps}.
      *
      * @var string
      */
@@ -144,17 +144,17 @@ public function getCheckPermissions(): bool
     /**
      * Determine whether this bulk loader should respect create/edit/delete permissions.
      */
-    public function setCheckPermissions(bool $value): self
+    public function setCheckPermissions(bool $value): BulkLoader
     {
         $this->checkPermissions = $value;
         return $this;
     }
 
     /*
-     * Load the given file via {@link self::processAll()} and {@link self::processRecord()}.
+     * Load the given file via {@link BulkLoader::processAll()} and {@link BulkLoader::processRecord()}.
      * Optionally truncates (clear) the table before it imports.
      *
-     * @return BulkLoader_Result See {@link self::processAll()}
+     * @return BulkLoader_Result See {@link BulkLoader::processAll()}
      */
     public function load($filepath)
     {
@@ -190,7 +190,7 @@ public function load($filepath)
      * it through a UI.
      *
      * @param string $filepath Absolute path to the file we're importing
-     * @return array See {@link self::processAll()}
+     * @return array See {@link BulkLoader::processAll()}
      */
     abstract public function preview($filepath);
 
@@ -208,7 +208,7 @@ abstract protected function processAll($filepath, $preview = false);
     /**
      * Process a single record from the file.
      *
-     * @param array $record An map of the data, keyed by the header field defined in {@link self::$columnMap}
+     * @param array $record An map of the data, keyed by the header field defined in {@link BulkLoader::$columnMap}
      * @param array $columnMap
      * @param $result BulkLoader_Result (passed as reference)
      * @param boolean $preview
@@ -286,7 +286,7 @@ public function getImportSpec()
      * so this is mainly a customization method.
      *
      * @param mixed $val
-     * @param string $fieldName Name of the field as specified in the array-values for {@link self::$columnMap}.
+     * @param string $fieldName Name of the field as specified in the array-values for {@link BulkLoader::$columnMap}.
      * @return boolean
      */
     protected function isNullValue($val, $fieldName = null)
diff --git a/src/Dev/CLI.php b/src/Dev/CLI.php
index 2bb2d807022..eeb24972e61 100644
--- a/src/Dev/CLI.php
+++ b/src/Dev/CLI.php
@@ -37,13 +37,13 @@ public static function supports_colour()
      */
     public static function text($text, $fgColour = null, $bgColour = null, $bold = false)
     {
-        if (!self::supports_colour()) {
+        if (!CLI::supports_colour()) {
             return $text;
         }
 
         if ($fgColour || $bgColour || $bold) {
-            $prefix = self::start_colour($fgColour, $bgColour, $bold);
-            $suffix = self::end_colour();
+            $prefix = CLI::start_colour($fgColour, $bgColour, $bold);
+            $suffix = CLI::end_colour();
         } else {
             $prefix = $suffix = "";
         }
@@ -62,7 +62,7 @@ public static function text($text, $fgColour = null, $bgColour = null, $bold = f
      */
     public static function start_colour($fgColour = null, $bgColour = null, $bold = false)
     {
-        if (!self::supports_colour()) {
+        if (!CLI::supports_colour()) {
             return "";
         }
         $colours = [
@@ -98,6 +98,6 @@ public static function start_colour($fgColour = null, $bgColour = null, $bold =
      */
     public static function end_colour()
     {
-        return self::supports_colour() ? "\033[0m" : "";
+        return CLI::supports_colour() ? "\033[0m" : "";
     }
 }
diff --git a/src/Dev/CliDebugView.php b/src/Dev/CliDebugView.php
index 44121bf780a..907316cace6 100644
--- a/src/Dev/CliDebugView.php
+++ b/src/Dev/CliDebugView.php
@@ -43,10 +43,10 @@ public function renderFooter()
      */
     public function renderError($httpRequest, $errno, $errstr, $errfile, $errline)
     {
-        if (!isset(self::$error_types[$errno])) {
+        if (!isset(CliDebugView::$error_types[$errno])) {
             $errorTypeTitle = "UNKNOWN TYPE, ERRNO $errno";
         } else {
-            $errorTypeTitle = self::$error_types[$errno]['title'];
+            $errorTypeTitle = CliDebugView::$error_types[$errno]['title'];
         }
         $output = CLI::text("ERROR [" . $errorTypeTitle . "]: $errstr\nIN $httpRequest\n", "red", null, true);
         $output .= CLI::text("Line $errline in $errfile\n\n", "red");
@@ -67,7 +67,7 @@ public function renderSourceFragment($lines, $errline)
         foreach ($lines as $offset => $line) {
             $output .= ($offset == $errline) ? "* " : "  ";
             $output .= str_pad("$offset:", 5);
-            $output .= wordwrap($line ?? '', self::config()->columns ?? 0, "\n       ");
+            $output .= wordwrap($line ?? '', CliDebugView::config()->columns ?? 0, "\n       ");
         }
         $output .= "\n";
 
@@ -90,7 +90,7 @@ public function renderTrace($trace = null)
 
     public function renderParagraph($text)
     {
-        return wordwrap($text ?? '', self::config()->columns ?? 0) . "\n\n";
+        return wordwrap($text ?? '', CliDebugView::config()->columns ?? 0) . "\n\n";
     }
 
     /**
@@ -103,10 +103,10 @@ public function renderParagraph($text)
      */
     public function renderInfo($title, $subtitle, $description = null)
     {
-        $output = wordwrap(strtoupper($title ?? ''), self::config()->columns ?? 0) . "\n";
-        $output .= wordwrap($subtitle ?? '', self::config()->columns ?? 0) . "\n";
-        $output .= str_repeat('-', min(self::config()->columns, max(strlen($title ?? ''), strlen($subtitle ?? ''))) ?? 0) . "\n";
-        $output .= wordwrap($description ?? '', self::config()->columns ?? 0) . "\n\n";
+        $output = wordwrap(strtoupper($title ?? ''), CliDebugView::config()->columns ?? 0) . "\n";
+        $output .= wordwrap($subtitle ?? '', CliDebugView::config()->columns ?? 0) . "\n";
+        $output .= str_repeat('-', min(CliDebugView::config()->columns, max(strlen($title ?? ''), strlen($subtitle ?? ''))) ?? 0) . "\n";
+        $output .= wordwrap($description ?? '', CliDebugView::config()->columns ?? 0) . "\n\n";
 
         return $output;
     }
@@ -114,17 +114,17 @@ public function renderInfo($title, $subtitle, $description = null)
     public function renderVariable($val, $caller)
     {
         $output = PHP_EOL;
-        $output .= CLI::text(str_repeat('=', self::config()->columns ?? 0), 'green');
+        $output .= CLI::text(str_repeat('=', CliDebugView::config()->columns ?? 0), 'green');
         $output .= PHP_EOL;
         $output .= CLI::text($this->formatCaller($caller), 'blue', null, true);
         $output .= PHP_EOL . PHP_EOL;
         if (is_string($val)) {
-            $output .= wordwrap($val ?? '', self::config()->columns ?? 0);
+            $output .= wordwrap($val ?? '', CliDebugView::config()->columns ?? 0);
         } else {
             $output .= var_export($val, true);
         }
         $output .= PHP_EOL;
-        $output .= CLI::text(str_repeat('=', self::config()->columns ?? 0), 'green');
+        $output .= CLI::text(str_repeat('=', CliDebugView::config()->columns ?? 0), 'green');
         $output .= PHP_EOL;
 
         return $output;
@@ -184,7 +184,7 @@ public function debugVariableText($val)
 
         // Format text
         if (is_string($val)) {
-            return wordwrap($val ?? '', self::config()->columns ?? 0);
+            return wordwrap($val ?? '', CliDebugView::config()->columns ?? 0);
         }
 
         // Other
diff --git a/src/Dev/CsvBulkLoader.php b/src/Dev/CsvBulkLoader.php
index 54c1e3eb650..edcfa25b293 100644
--- a/src/Dev/CsvBulkLoader.php
+++ b/src/Dev/CsvBulkLoader.php
@@ -325,7 +325,7 @@ protected function processRecord($record, $columnMap, &$results, $preview = fals
 
     /**
      * Find an existing objects based on one or more uniqueness columns
-     * specified via {@link self::$duplicateChecks}.
+     * specified via {@link CsvBulkLoader::$duplicateChecks}.
      *
      * @param array $record CSV data column
      * @param array $columnMap
@@ -380,7 +380,7 @@ public function findExistingObject($record, $columnMap = [])
 
     /**
      * Determine whether any loaded files should be parsed with a
-     * header-row (otherwise we rely on {@link self::$columnMap}.
+     * header-row (otherwise we rely on {@link CsvBulkLoader::$columnMap}.
      *
      * @return boolean
      */
diff --git a/src/Dev/Debug.php b/src/Dev/Debug.php
index 2f759d512cd..5701577f08f 100644
--- a/src/Dev/Debug.php
+++ b/src/Dev/Debug.php
@@ -102,8 +102,8 @@ public static function endshow($val, $showHeader = true, HTTPRequest $request =
      */
     public static function dump($val, HTTPRequest $request = null)
     {
-        echo self::create_debug_view($request)
-            ->renderVariable($val, self::caller());
+        echo Debug::create_debug_view($request)
+            ->renderVariable($val, Debug::caller());
     }
 
     /**
diff --git a/src/Dev/DebugView.php b/src/Dev/DebugView.php
index 4e5c4bc87a5..f50611154f7 100644
--- a/src/Dev/DebugView.php
+++ b/src/Dev/DebugView.php
@@ -214,7 +214,7 @@ public function renderFooter()
      */
     public function renderError($httpRequest, $errno, $errstr, $errfile, $errline)
     {
-        $errorType = isset(self::$error_types[$errno]) ? self::$error_types[$errno] : self::$unknown_error;
+        $errorType = isset(DebugView::$error_types[$errno]) ? DebugView::$error_types[$errno] : DebugView::$unknown_error;
         $httpRequestEnt = htmlentities($httpRequest ?? '', ENT_COMPAT, 'UTF-8');
         if (filter_var(ini_get('html_errors'), FILTER_VALIDATE_BOOL)) {
             $errstr = strip_tags($errstr ?? '');
@@ -308,7 +308,7 @@ public function renderVariable($val, $caller)
         $output = '<pre style="background-color:#ccc;padding:5px;font-size:14px;line-height:18px;">';
         $output .= "<span style=\"font-size: 12px;color:#666;\">" . $this->formatCaller($caller) . " - </span>\n";
         if (is_string($val)) {
-            $output .= wordwrap($val ?? '', self::config()->columns ?? 0);
+            $output .= wordwrap($val ?? '', DebugView::config()->columns ?? 0);
         } else {
             $output .= var_export($val, true);
         }
diff --git a/src/Dev/Deprecation.php b/src/Dev/Deprecation.php
index eefc1b36dab..9c7d4f5dab1 100644
--- a/src/Dev/Deprecation.php
+++ b/src/Dev/Deprecation.php
@@ -111,14 +111,14 @@ public static function disable(): void
      */
     public static function withNoReplacement(callable $func)
     {
-        if (self::$insideWithNoReplacement) {
+        if (Deprecation::$insideWithNoReplacement) {
             return $func();
         }
-        self::$insideWithNoReplacement = true;
+        Deprecation::$insideWithNoReplacement = true;
         try {
             return $func();
         } finally {
-            self::$insideWithNoReplacement = false;
+            Deprecation::$insideWithNoReplacement = false;
         }
     }
 
@@ -138,7 +138,7 @@ protected static function get_called_method_from_trace($backtrace, $level = 1)
         }
         $newLevel = $level;
         // handle closures inside withNoReplacement()
-        if (self::$insideWithNoReplacement
+        if (Deprecation::$insideWithNoReplacement
             && substr($backtrace[$newLevel]['function'], -strlen('{closure}')) === '{closure}'
         ) {
             $newLevel = $newLevel + 2;
@@ -184,7 +184,7 @@ public static function isEnabled(): bool
      */
     public static function isTriggeringError(): bool
     {
-        return self::$isTriggeringError;
+        return Deprecation::$isTriggeringError;
     }
 
     /**
@@ -195,7 +195,7 @@ public static function isTriggeringError(): bool
      */
     public static function setShouldShowForHttp(bool $value): void
     {
-        self::$shouldShowForHttp = $value;
+        Deprecation::$shouldShowForHttp = $value;
     }
 
     /**
@@ -206,7 +206,7 @@ public static function setShouldShowForHttp(bool $value): void
      */
     public static function setShouldShowForCli(bool $value): void
     {
-        self::$shouldShowForCli = $value;
+        Deprecation::$shouldShowForCli = $value;
     }
 
     /**
@@ -217,9 +217,9 @@ public static function shouldShowForHttp(): bool
     {
         if (Environment::hasEnv('SS_DEPRECATION_SHOW_HTTP')) {
             $envVar = Environment::getEnv('SS_DEPRECATION_SHOW_HTTP');
-            return self::varAsBoolean($envVar);
+            return Deprecation::varAsBoolean($envVar);
         }
-        return self::$shouldShowForHttp;
+        return Deprecation::$shouldShowForHttp;
     }
 
     /**
@@ -230,34 +230,34 @@ public static function shouldShowForCli(): bool
     {
         if (Environment::hasEnv('SS_DEPRECATION_SHOW_CLI')) {
             $envVar = Environment::getEnv('SS_DEPRECATION_SHOW_CLI');
-            return self::varAsBoolean($envVar);
+            return Deprecation::varAsBoolean($envVar);
         }
-        return self::$shouldShowForCli;
+        return Deprecation::$shouldShowForCli;
     }
 
     public static function outputNotices(): void
     {
-        if (!self::isEnabled()) {
+        if (!Deprecation::isEnabled()) {
             return;
         }
 
         $count = 0;
-        $origCount = count(self::$userErrorMessageBuffer);
+        $origCount = count(Deprecation::$userErrorMessageBuffer);
         while ($origCount > $count) {
             $count++;
-            $arr = array_shift(self::$userErrorMessageBuffer);
+            $arr = array_shift(Deprecation::$userErrorMessageBuffer);
             $message = $arr['message'];
             $calledInsideWithNoReplacement = $arr['calledInsideWithNoReplacement'];
-            if ($calledInsideWithNoReplacement && !self::$showNoReplacementNotices) {
+            if ($calledInsideWithNoReplacement && !Deprecation::$showNoReplacementNotices) {
                 continue;
             }
-            self::$isTriggeringError = true;
+            Deprecation::$isTriggeringError = true;
             user_error($message, E_USER_DEPRECATED);
-            self::$isTriggeringError = false;
+            Deprecation::$isTriggeringError = false;
         }
         // Make absolutely sure the buffer is empty - array_shift seems to leave an item in the array
         // if we're not using numeric keys.
-        self::$userErrorMessageBuffer = [];
+        Deprecation::$userErrorMessageBuffer = [];
     }
 
     /**
@@ -278,17 +278,17 @@ public static function notice($atVersion, $string = '', $scope = Deprecation::SC
         // calls something else that calls Deprecation::notice()
         try {
             $data = null;
-            if ($scope === self::SCOPE_CONFIG) {
+            if ($scope === Deprecation::SCOPE_CONFIG) {
                 // Deprecated config set via yaml will only be shown in the browser when using ?flush=1
                 // It will not show in CLI when running dev/build flush=1
                 $data = [
                     'key' => sha1($string),
                     'message' => $string,
-                    'calledInsideWithNoReplacement' => self::$insideWithNoReplacement
+                    'calledInsideWithNoReplacement' => Deprecation::$insideWithNoReplacement
                 ];
             } else {
-                if (!self::isEnabled()) {
-                    // Do not add to self::$userErrorMessageBuffer, as the backtrace is too expensive
+                if (!Deprecation::isEnabled()) {
+                    // Do not add to Deprecation::$userErrorMessageBuffer, as the backtrace is too expensive
                     return;
                 }
 
@@ -298,7 +298,7 @@ public static function notice($atVersion, $string = '', $scope = Deprecation::SC
                 // Get the calling scope
                 if ($scope == Deprecation::SCOPE_METHOD) {
                     $backtrace = debug_backtrace(0);
-                    $caller = self::get_called_method_from_trace($backtrace, 1);
+                    $caller = Deprecation::get_called_method_from_trace($backtrace, 1);
                 } elseif ($scope == Deprecation::SCOPE_CLASS) {
                     $backtrace = debug_backtrace(0);
                     $caller = isset($backtrace[1]['class']) ? $backtrace[1]['class'] : '(unknown)';
@@ -310,8 +310,8 @@ public static function notice($atVersion, $string = '', $scope = Deprecation::SC
                     $string .= ".";
                 }
 
-                $level = self::$insideWithNoReplacement ? 4 : 2;
-                $string .= " Called from " . self::get_called_method_from_trace($backtrace, $level) . '.';
+                $level = Deprecation::$insideWithNoReplacement ? 4 : 2;
+                $string .= " Called from " . Deprecation::get_called_method_from_trace($backtrace, $level) . '.';
 
                 if ($caller) {
                     $string = $caller . ' is deprecated.' . ($string ? ' ' . $string : '');
@@ -319,22 +319,22 @@ public static function notice($atVersion, $string = '', $scope = Deprecation::SC
                 $data = [
                     'key' => sha1($string),
                     'message' => $string,
-                    'calledInsideWithNoReplacement' => self::$insideWithNoReplacement
+                    'calledInsideWithNoReplacement' => Deprecation::$insideWithNoReplacement
                 ];
             }
-            if ($data && !array_key_exists($data['key'], self::$userErrorMessageBuffer)) {
+            if ($data && !array_key_exists($data['key'], Deprecation::$userErrorMessageBuffer)) {
                 // Store de-duplicated data in a buffer to be outputted when outputNotices() is called
-                self::$userErrorMessageBuffer[$data['key']] = $data;
+                Deprecation::$userErrorMessageBuffer[$data['key']] = $data;
 
                 // Use a shutdown function rather than immediately calling user_error() so that notices
                 // do not interfere with setting session varibles i.e. headers already sent error
                 // it also means the deprecation notices appear below all phpunit output in CI
                 // which is far nicer than having it spliced between phpunit output
-                if (!self::$haveSetShutdownFunction && self::isEnabled()) {
+                if (!Deprecation::$haveSetShutdownFunction && Deprecation::isEnabled()) {
                     register_shutdown_function(function () {
-                        self::outputNotices();
+                        Deprecation::outputNotices();
                     });
-                    self::$haveSetShutdownFunction = true;
+                    Deprecation::$haveSetShutdownFunction = true;
                 }
             }
         } catch (BadMethodCallException $e) {
diff --git a/src/Dev/Install/DatabaseAdapterRegistry.php b/src/Dev/Install/DatabaseAdapterRegistry.php
index 0a77da8075e..4607e44720b 100644
--- a/src/Dev/Install/DatabaseAdapterRegistry.php
+++ b/src/Dev/Install/DatabaseAdapterRegistry.php
@@ -96,10 +96,10 @@ public static function register($config)
 
         // set default fields if none are defined already
         if (!isset($config['fields'])) {
-            $config['fields'] = self::$default_fields;
+            $config['fields'] = DatabaseAdapterRegistry::$default_fields;
         }
 
-        self::$adapters[$config['class']] = $config;
+        DatabaseAdapterRegistry::$adapters[$config['class']] = $config;
     }
 
     /**
@@ -109,7 +109,7 @@ public static function register($config)
      */
     public static function unregister($class)
     {
-        unset(self::$adapters[$class]);
+        unset(DatabaseAdapterRegistry::$adapters[$class]);
     }
 
     /**
@@ -204,7 +204,7 @@ public static function flush()
      */
     public static function get_adapters()
     {
-        return self::$adapters;
+        return DatabaseAdapterRegistry::$adapters;
     }
 
     /**
@@ -215,8 +215,8 @@ public static function get_adapters()
      */
     public static function get_adapter($class)
     {
-        if (isset(self::$adapters[$class])) {
-            return self::$adapters[$class];
+        if (isset(DatabaseAdapterRegistry::$adapters[$class])) {
+            return DatabaseAdapterRegistry::$adapters[$class];
         }
         return null;
     }
@@ -228,7 +228,7 @@ public static function get_adapter($class)
      */
     public static function get_default_fields()
     {
-        return self::$default_fields;
+        return DatabaseAdapterRegistry::$default_fields;
     }
 
     /**
diff --git a/src/Dev/SapphireTest.php b/src/Dev/SapphireTest.php
index 3694f18ae42..303c22a92d0 100644
--- a/src/Dev/SapphireTest.php
+++ b/src/Dev/SapphireTest.php
@@ -206,7 +206,7 @@ public static function getRequiredExtensions()
      */
     protected static function is_running_test()
     {
-        return self::$is_running_test;
+        return SapphireTest::$is_running_test;
     }
 
     /**
@@ -216,7 +216,7 @@ protected static function is_running_test()
      */
     protected static function set_is_running_test($bool)
     {
-        self::$is_running_test = $bool;
+        SapphireTest::$is_running_test = $bool;
     }
 
     /**
@@ -653,7 +653,7 @@ public static function assertEmailSent($to, $from = null, $subject = null, $cont
     public static function assertListContains($matches, SS_List $list, $message = '')
     {
         if (!is_array($matches)) {
-            throw self::createInvalidArgumentException(
+            throw SapphireTest::createInvalidArgumentException(
                 1,
                 'array'
             );
@@ -691,7 +691,7 @@ public static function assertListContains($matches, SS_List $list, $message = ''
     public static function assertListNotContains($matches, SS_List $list, $message = '')
     {
         if (!is_array($matches)) {
-            throw self::createInvalidArgumentException(
+            throw SapphireTest::createInvalidArgumentException(
                 1,
                 'array'
             );
@@ -731,7 +731,7 @@ public static function assertListNotContains($matches, SS_List $list, $message =
     public static function assertListEquals($matches, SS_List $list, $message = '')
     {
         if (!is_array($matches)) {
-            throw self::createInvalidArgumentException(
+            throw SapphireTest::createInvalidArgumentException(
                 1,
                 'array'
             );
@@ -762,7 +762,7 @@ public static function assertListEquals($matches, SS_List $list, $message = '')
     public static function assertListAllMatch($match, SS_List $list, $message = '')
     {
         if (!is_array($match)) {
-            throw self::createInvalidArgumentException(
+            throw SapphireTest::createInvalidArgumentException(
                 1,
                 'array'
             );
diff --git a/src/Dev/TestKernel.php b/src/Dev/TestKernel.php
index 67229f5cae1..2e501b150eb 100644
--- a/src/Dev/TestKernel.php
+++ b/src/Dev/TestKernel.php
@@ -11,7 +11,7 @@ class TestKernel extends CoreKernel
 {
     public function __construct($basePath)
     {
-        $this->setEnvironment(self::DEV);
+        $this->setEnvironment(TestKernel::DEV);
         parent::__construct($basePath);
     }
 
@@ -23,7 +23,7 @@ public function __construct($basePath)
      */
     public function reset()
     {
-        $this->setEnvironment(self::DEV);
+        $this->setEnvironment(TestKernel::DEV);
         $this->bootPHP();
         return $this;
     }
diff --git a/src/Dev/Validation/RelationValidationService.php b/src/Dev/Validation/RelationValidationService.php
index 0b85bbbbf61..2b1b7e7201c 100644
--- a/src/Dev/Validation/RelationValidationService.php
+++ b/src/Dev/Validation/RelationValidationService.php
@@ -82,7 +82,7 @@ public function clearErrors(): void
 
     public static function reset(): void
     {
-        $service = self::singleton();
+        $service = RelationValidationService::singleton();
         $service->clearErrors();
         $service->ignoreConfig = false;
     }
@@ -98,7 +98,7 @@ public static function reset(): void
      */
     public function validateRelations(): array
     {
-        self::reset();
+        RelationValidationService::reset();
         $classes = ClassInfo::subclassesFor(DataObject::class);
 
         return $this->validateClasses($classes);
@@ -139,7 +139,7 @@ public function executeValidation(): void
      */
     public function inspectClasses(array $classes): array
     {
-        self::reset();
+        RelationValidationService::reset();
         $this->ignoreConfig = true;
 
         return $this->validateClasses($classes);
diff --git a/src/Forms/ConfirmedPasswordField.php b/src/Forms/ConfirmedPasswordField.php
index bdabb9beaba..fa61dc91a38 100644
--- a/src/Forms/ConfirmedPasswordField.php
+++ b/src/Forms/ConfirmedPasswordField.php
@@ -48,7 +48,7 @@ class ConfirmedPasswordField extends FormField
     /**
      * Allow empty fields when entering the password for the first time
      * If this is set to true then a random password may be generated if the field is empty
-     * depending on the value of $self::generateRandomPasswordOnEmtpy
+     * depending on the value of $ConfirmedPasswordField::generateRandomPasswordOnEmtpy
      *
      * @var boolean
      */
diff --git a/src/Forms/Form.php b/src/Forms/Form.php
index 111bbf1203e..27f90158325 100644
--- a/src/Forms/Form.php
+++ b/src/Forms/Form.php
@@ -278,7 +278,7 @@ class Form extends ViewableData implements HasRequestHandler
      */
     public function __construct(
         RequestHandler $controller = null,
-        $name = self::DEFAULT_NAME,
+        $name = Form::DEFAULT_NAME,
         FieldList $fields = null,
         FieldList $actions = null,
         Validator $validator = null
@@ -348,7 +348,7 @@ public function restoreFormState()
         // load data in from previous submission upon error
         $data = $this->getSessionData();
         if (isset($data)) {
-            $this->loadDataFrom($data, self::MERGE_AS_INTERNAL_VALUE);
+            $this->loadDataFrom($data, Form::MERGE_AS_INTERNAL_VALUE);
         }
         return $this;
     }
@@ -536,7 +536,7 @@ public function castingHelper($field)
      */
     protected function setupDefaultClasses()
     {
-        $defaultClasses = self::config()->get('default_classes');
+        $defaultClasses = Form::config()->get('default_classes');
         if ($defaultClasses) {
             foreach ($defaultClasses as $class) {
                 $this->addExtraClass($class);
@@ -560,7 +560,7 @@ public function getValidationResponseCallback()
      * in which case the default form behaviour will kick in.
      *
      * @param $callback
-     * @return self
+     * @return Form
      */
     public function setValidationResponseCallback($callback)
     {
@@ -954,12 +954,12 @@ public function getEncType()
         if ($fields = $this->fields->dataFields()) {
             foreach ($fields as $field) {
                 if ($field instanceof FileField) {
-                    return self::ENC_TYPE_MULTIPART;
+                    return Form::ENC_TYPE_MULTIPART;
                 }
             }
         }
 
-        return self::ENC_TYPE_URLENCODED;
+        return Form::ENC_TYPE_URLENCODED;
     }
 
     /**
@@ -1343,7 +1343,7 @@ public function loadDataFrom($data, $mergeStrategy = 0, $fieldList = null)
 
         // Handle the backwards compatible case of passing "true" as the second argument
         if ($mergeStrategy === true) {
-            $mergeStrategy = self::MERGE_CLEAR_MISSING;
+            $mergeStrategy = Form::MERGE_CLEAR_MISSING;
         } elseif ($mergeStrategy === false) {
             $mergeStrategy = 0;
         }
@@ -1359,9 +1359,9 @@ public function loadDataFrom($data, $mergeStrategy = 0, $fieldList = null)
 
         // Using the `MERGE_AS_INTERNAL_VALUE` or `MERGE_AS_SUBMITTED_VALUE` flags users can explicitly specify which
         // `setValue` method to use.
-        if (($mergeStrategy & self::MERGE_AS_INTERNAL_VALUE) == self::MERGE_AS_INTERNAL_VALUE) {
+        if (($mergeStrategy & Form::MERGE_AS_INTERNAL_VALUE) == Form::MERGE_AS_INTERNAL_VALUE) {
             $submitted = false;
-        } elseif (($mergeStrategy & self::MERGE_AS_SUBMITTED_VALUE) == self::MERGE_AS_SUBMITTED_VALUE) {
+        } elseif (($mergeStrategy & Form::MERGE_AS_SUBMITTED_VALUE) == Form::MERGE_AS_SUBMITTED_VALUE) {
             $submitted = true;
         }
 
@@ -1455,10 +1455,10 @@ public function loadDataFrom($data, $mergeStrategy = 0, $fieldList = null)
             // save to the field if either a value is given, or loading of blank/undefined values is forced
             $setValue = false;
             if ($exists) {
-                if ($val != false || ($mergeStrategy & self::MERGE_IGNORE_FALSEISH) != self::MERGE_IGNORE_FALSEISH) {
+                if ($val != false || ($mergeStrategy & Form::MERGE_IGNORE_FALSEISH) != Form::MERGE_IGNORE_FALSEISH) {
                     $setValue = true;
                 }
-            } elseif (($mergeStrategy & self::MERGE_CLEAR_MISSING) == self::MERGE_CLEAR_MISSING) {
+            } elseif (($mergeStrategy & Form::MERGE_CLEAR_MISSING) == Form::MERGE_CLEAR_MISSING) {
                 $setValue = true;
             }
 
diff --git a/src/Forms/FormFactory.php b/src/Forms/FormFactory.php
index 7571418ba98..b900fbcd2fd 100644
--- a/src/Forms/FormFactory.php
+++ b/src/Forms/FormFactory.php
@@ -25,7 +25,7 @@ interface FormFactory
      * Custom factories may support more advanced parameters.
      * @return Form
      */
-    public function getForm(RequestHandler $controller = null, $name = self::DEFAULT_NAME, $context = []);
+    public function getForm(RequestHandler $controller = null, $name = FormFactory::DEFAULT_NAME, $context = []);
 
     /**
      * Return list of mandatory context keys
diff --git a/src/Forms/FormField.php b/src/Forms/FormField.php
index c6a56ece7e6..77a46ef2c18 100644
--- a/src/Forms/FormField.php
+++ b/src/Forms/FormField.php
@@ -238,7 +238,7 @@ class FormField extends RequestHandler
      *     or simply be a block of stand-alone content. As with 'Custom',
      *     the component property is mandatory if this is assigned.
      *
-     * Each value has an equivalent constant, e.g. {@link self::SCHEMA_DATA_TYPE_STRING}.
+     * Each value has an equivalent constant, e.g. {@link FormField::SCHEMA_DATA_TYPE_STRING}.
      *
      * @var string
      */
@@ -333,7 +333,7 @@ public function __construct($name, $title = null, $value = null)
         $this->setName($name);
 
         if ($title === null) {
-            $this->title = self::name_to_label($name);
+            $this->title = FormField::name_to_label($name);
         } else {
             $this->title = $title;
         }
@@ -1566,7 +1566,7 @@ public function getTitleTip(): ?Tip
      * @param Tip|null $tip
      * @return $this
      */
-    public function setTitleTip(?Tip $tip): self
+    public function setTitleTip(?Tip $tip): FormField
     {
         $this->titleTip = $tip;
         return $this;
diff --git a/src/Forms/GridField/GridField.php b/src/Forms/GridField/GridField.php
index d42fb7b34e9..5908b95aae6 100644
--- a/src/Forms/GridField/GridField.php
+++ b/src/Forms/GridField/GridField.php
@@ -558,11 +558,11 @@ public function FieldHolder($properties = [])
 
         // Continue looping if any placeholders exist
         while (array_filter($content ?? [], function ($value) {
-            return preg_match(self::FRAGMENT_REGEX ?? '', $value ?? '');
+            return preg_match(GridField::FRAGMENT_REGEX ?? '', $value ?? '');
         })) {
             foreach ($content as $contentKey => $contentValue) {
                 // Skip if this specific content has no placeholders
-                if (!preg_match_all(self::FRAGMENT_REGEX ?? '', $contentValue ?? '', $matches)) {
+                if (!preg_match_all(GridField::FRAGMENT_REGEX ?? '', $contentValue ?? '', $matches)) {
                     continue;
                 }
                 foreach ($matches[1] as $match) {
@@ -578,7 +578,7 @@ public function FieldHolder($properties = [])
                     // If the fragment still has a fragment definition in it, when we should defer
                     // this item until later.
 
-                    if (preg_match(self::FRAGMENT_REGEX ?? '', $fragment ?? '', $matches)) {
+                    if (preg_match(GridField::FRAGMENT_REGEX ?? '', $fragment ?? '', $matches)) {
                         if (isset($fragmentDeferred[$contentKey]) && $fragmentDeferred[$contentKey] > 5) {
                             throw new LogicException(sprintf(
                                 'GridField HTML fragment "%s" and "%s" appear to have a circular dependency.',
diff --git a/src/Forms/GridField/GridFieldDetailForm.php b/src/Forms/GridField/GridFieldDetailForm.php
index 07299cc93fd..e776f333daa 100644
--- a/src/Forms/GridField/GridFieldDetailForm.php
+++ b/src/Forms/GridField/GridFieldDetailForm.php
@@ -285,7 +285,7 @@ public function getName()
      * database, and the record has a CMSEditLink method, then the system will redirect to the
      * URL returned by that method.
      */
-    public function setRedirectMissingRecords(bool $redirectMissingRecords): self
+    public function setRedirectMissingRecords(bool $redirectMissingRecords): GridFieldDetailForm
     {
         $this->redirectMissingRecords = $redirectMissingRecords;
         return $this;
diff --git a/src/Forms/GridField/GridFieldFilterHeader.php b/src/Forms/GridField/GridFieldFilterHeader.php
index 1fb47d2499d..2e96e28f889 100755
--- a/src/Forms/GridField/GridFieldFilterHeader.php
+++ b/src/Forms/GridField/GridFieldFilterHeader.php
@@ -92,7 +92,7 @@ public function getSearchField(): ?string
         return $this->searchField;
     }
 
-    public function setSearchField(string $field): self
+    public function setSearchField(string $field): GridFieldFilterHeader
     {
         $this->searchField = $field;
         return $this;
diff --git a/src/Forms/GridField/GridState_Data.php b/src/Forms/GridField/GridState_Data.php
index 2bbc7d791f4..f74c60a2377 100644
--- a/src/Forms/GridField/GridState_Data.php
+++ b/src/Forms/GridField/GridState_Data.php
@@ -25,14 +25,14 @@ public function __construct($data = [])
 
     public function __get($name)
     {
-        return $this->getData($name, new self());
+        return $this->getData($name, new GridState_Data());
     }
 
     public function __call($name, $arguments)
     {
         // Assume first parameter is default value
         if (empty($arguments)) {
-            $default = new self();
+            $default = new GridState_Data();
         } else {
             $default = $arguments[0];
         }
@@ -72,7 +72,7 @@ public function getData($name, $default = null)
             $this->data[$name] = $default;
         } else {
             if (is_array($this->data[$name])) {
-                $this->data[$name] = new self($this->data[$name]);
+                $this->data[$name] = new GridState_Data($this->data[$name]);
             }
         }
 
diff --git a/src/Forms/HTMLEditor/HTMLEditorConfig.php b/src/Forms/HTMLEditor/HTMLEditorConfig.php
index 824d11f73c7..6c685bf29c5 100644
--- a/src/Forms/HTMLEditor/HTMLEditorConfig.php
+++ b/src/Forms/HTMLEditor/HTMLEditorConfig.php
@@ -81,11 +81,11 @@ public static function get($identifier = null)
             return static::get_active();
         }
         // Create new instance if unconfigured
-        if (!isset(self::$configs[$identifier])) {
-            self::$configs[$identifier] = static::create();
-            self::$configs[$identifier]->setOption('editorIdentifier', $identifier);
+        if (!isset(HTMLEditorConfig::$configs[$identifier])) {
+            HTMLEditorConfig::$configs[$identifier] = static::create();
+            HTMLEditorConfig::$configs[$identifier]->setOption('editorIdentifier', $identifier);
         }
-        return self::$configs[$identifier];
+        return HTMLEditorConfig::$configs[$identifier];
     }
 
     /**
@@ -98,10 +98,10 @@ public static function get($identifier = null)
     public static function set_config($identifier, HTMLEditorConfig $config = null)
     {
         if ($config) {
-            self::$configs[$identifier] = $config;
-            self::$configs[$identifier]->setOption('editorIdentifier', $identifier);
+            HTMLEditorConfig::$configs[$identifier] = $config;
+            HTMLEditorConfig::$configs[$identifier]->setOption('editorIdentifier', $identifier);
         } else {
-            unset(self::$configs[$identifier]);
+            unset(HTMLEditorConfig::$configs[$identifier]);
         }
         return $config;
     }
@@ -136,7 +136,7 @@ public static function setThemes($themes)
      */
     public static function set_active_identifier($identifier)
     {
-        self::$current = $identifier;
+        HTMLEditorConfig::$current = $identifier;
     }
 
     /**
@@ -147,7 +147,7 @@ public static function set_active_identifier($identifier)
      */
     public static function get_active_identifier()
     {
-        $identifier = self::$current ?: static::config()->get('default_config');
+        $identifier = HTMLEditorConfig::$current ?: static::config()->get('default_config');
         return $identifier;
     }
 
@@ -158,8 +158,8 @@ public static function get_active_identifier()
      */
     public static function get_active()
     {
-        $identifier = self::get_active_identifier();
-        return self::get($identifier);
+        $identifier = HTMLEditorConfig::get_active_identifier();
+        return HTMLEditorConfig::get($identifier);
     }
 
     /**
@@ -184,7 +184,7 @@ public static function get_available_configs_map()
     {
         $configs = [];
 
-        foreach (self::$configs as $identifier => $config) {
+        foreach (HTMLEditorConfig::$configs as $identifier => $config) {
             $configs[$identifier] = $config->getOption('friendly_name');
         }
 
diff --git a/src/Forms/HTMLEditor/TinyMCEConfig.php b/src/Forms/HTMLEditor/TinyMCEConfig.php
index 80621abd086..e7d2628c36e 100644
--- a/src/Forms/HTMLEditor/TinyMCEConfig.php
+++ b/src/Forms/HTMLEditor/TinyMCEConfig.php
@@ -721,7 +721,7 @@ protected function getConfig()
     private function initImageSizePresets(array &$settings): void
     {
         if (empty($settings['image_size_presets'])) {
-            $settings['image_size_presets'] = self::config()->get('image_size_presets');
+            $settings['image_size_presets'] = TinyMCEConfig::config()->get('image_size_presets');
         }
 
         foreach ($settings['image_size_presets'] as &$preset) {
@@ -736,7 +736,7 @@ private function initImageSizePresets(array &$settings): void
                 );
             } elseif (empty($preset['text']) && isset($preset['width'])) {
                 $preset['text'] = _t(
-                    self::class . '.PIXEL_WIDTH',
+                    TinyMCEConfig::class . '.PIXEL_WIDTH',
                     '{width} pixels',
                     $preset
                 );
@@ -926,7 +926,7 @@ public function getTinyMCEResource()
      * @param string $folderName
      * @return $this
      */
-    public function setFolderName(string $folderName): self
+    public function setFolderName(string $folderName): TinyMCEConfig
     {
         $folder = Folder::find_or_make($folderName);
         $folderID = $folder ? $folder->ID : null;
@@ -937,9 +937,9 @@ public function setFolderName(string $folderName): self
     public function provideI18nEntities()
     {
         $entities = [
-            self::class . '.PIXEL_WIDTH' => '{width} pixels',
+            TinyMCEConfig::class . '.PIXEL_WIDTH' => '{width} pixels',
         ];
-        foreach (self::config()->get('image_size_presets') as $preset) {
+        foreach (TinyMCEConfig::config()->get('image_size_presets') as $preset) {
             if (empty($preset['i18n']) || empty($preset['text'])) {
                 continue;
             }
diff --git a/src/Forms/HTMLReadonlyField.php b/src/Forms/HTMLReadonlyField.php
index 8a028726d5e..64bb339e30f 100644
--- a/src/Forms/HTMLReadonlyField.php
+++ b/src/Forms/HTMLReadonlyField.php
@@ -14,7 +14,7 @@ class HTMLReadonlyField extends ReadonlyField
         'ValueEntities' => 'HTMLFragment',
     ];
 
-    protected $schemaDataType = self::SCHEMA_DATA_TYPE_STRUCTURAL;
+    protected $schemaDataType = HTMLReadonlyField::SCHEMA_DATA_TYPE_STRUCTURAL;
 
     /**
      * @var string
diff --git a/src/Forms/HeaderField.php b/src/Forms/HeaderField.php
index 610f6d82d05..fa574c43935 100644
--- a/src/Forms/HeaderField.php
+++ b/src/Forms/HeaderField.php
@@ -17,7 +17,7 @@ class HeaderField extends DatalessField
      */
     protected $headingLevel = 2;
 
-    protected $schemaDataType = self::SCHEMA_DATA_TYPE_STRUCTURAL;
+    protected $schemaDataType = HeaderField::SCHEMA_DATA_TYPE_STRUCTURAL;
 
     /**
      * @var string
diff --git a/src/Forms/LiteralField.php b/src/Forms/LiteralField.php
index 178cd1f093f..d90b02a3c2d 100644
--- a/src/Forms/LiteralField.php
+++ b/src/Forms/LiteralField.php
@@ -26,7 +26,7 @@ class LiteralField extends DatalessField
      */
     protected $content;
 
-    protected $schemaDataType = self::SCHEMA_DATA_TYPE_STRUCTURAL;
+    protected $schemaDataType = LiteralField::SCHEMA_DATA_TYPE_STRUCTURAL;
 
     /**
      * @var string
diff --git a/src/Forms/SingleSelectField.php b/src/Forms/SingleSelectField.php
index b3a97be5eea..1dcd6b502ed 100644
--- a/src/Forms/SingleSelectField.php
+++ b/src/Forms/SingleSelectField.php
@@ -67,7 +67,7 @@ public function getDefaultValue()
 
     /**
      * @param boolean $bool
-     * @return self Self reference
+     * @return SingleSelectField Self reference
      */
     public function setHasEmptyDefault($bool)
     {
diff --git a/src/Forms/TextField.php b/src/Forms/TextField.php
index 4247afa6b67..49aa40b2c14 100644
--- a/src/Forms/TextField.php
+++ b/src/Forms/TextField.php
@@ -78,7 +78,7 @@ public function getTip(): ?Tip
      * @param Tip|null $tip The Tip to apply, or null to remove an existing one
      * @return $this
      */
-    public function setTip(?Tip $tip = null): self
+    public function setTip(?Tip $tip = null): TextField
     {
         $this->tip = $tip;
 
diff --git a/src/Forms/Tip.php b/src/Forms/Tip.php
index 79b6254580b..57e43aeb6a1 100644
--- a/src/Forms/Tip.php
+++ b/src/Forms/Tip.php
@@ -21,7 +21,7 @@ class Tip
 
     private const DEFAULT_ICON = 'lamp';
 
-    private const DEFAULT_IMPORTANCE_LEVEL = self::IMPORTANCE_LEVELS['NORMAL'];
+    private const DEFAULT_IMPORTANCE_LEVEL = Tip::IMPORTANCE_LEVELS['NORMAL'];
 
     /**
      * @var string The icon that should be used on the Tip button
@@ -46,8 +46,8 @@ class Tip
      */
     public function __construct(
         string $message,
-        string $importance_level = self::DEFAULT_IMPORTANCE_LEVEL,
-        string $icon = self::DEFAULT_ICON
+        string $importance_level = Tip::DEFAULT_IMPORTANCE_LEVEL,
+        string $icon = Tip::DEFAULT_ICON
     ) {
         $this->setMessage($message);
         $this->setIcon($icon);
@@ -81,9 +81,9 @@ public function getImportanceLevel(): string
      * @return Tip
      * @throws InvalidArgumentException
      */
-    public function setImportanceLevel(string $importance_level): self
+    public function setImportanceLevel(string $importance_level): Tip
     {
-        if (!in_array($importance_level, self::IMPORTANCE_LEVELS ?? [])) {
+        if (!in_array($importance_level, Tip::IMPORTANCE_LEVELS ?? [])) {
             throw new InvalidArgumentException(
                 'Provided importance level must be defined in Tip::IMPORTANCE_LEVELS'
             );
@@ -106,7 +106,7 @@ public function getIcon(): string
      * @param string $icon
      * @return Tip
      */
-    public function setIcon(string $icon): self
+    public function setIcon(string $icon): Tip
     {
         $this->icon = $icon;
 
@@ -125,7 +125,7 @@ public function getMessage(): string
      * @param string $message
      * @return Tip
      */
-    public function setMessage(string $message): self
+    public function setMessage(string $message): Tip
     {
         $this->message = $message;
 
diff --git a/src/Forms/TreeDropdownField.php b/src/Forms/TreeDropdownField.php
index b2f9952c9c1..c503c591aa3 100644
--- a/src/Forms/TreeDropdownField.php
+++ b/src/Forms/TreeDropdownField.php
@@ -57,7 +57,7 @@
  */
 class TreeDropdownField extends FormField implements HasOneRelationFieldInterface
 {
-    protected $schemaDataType = self::SCHEMA_DATA_TYPE_SINGLESELECT;
+    protected $schemaDataType = TreeDropdownField::SCHEMA_DATA_TYPE_SINGLESELECT;
 
     protected $schemaComponent = 'TreeDropdownField';
 
@@ -561,7 +561,7 @@ public function tree(HTTPRequest $request)
         } else {
             // Return basic html
             $html = $markingSet->renderChildren(
-                [self::class . '_HTML', 'type' => 'Includes'],
+                [TreeDropdownField::class . '_HTML', 'type' => 'Includes'],
                 $customised
             );
             return HTTPResponse::create()
@@ -894,10 +894,10 @@ public function getSchemaStateDefaults()
     protected function getCacheKey()
     {
         $target = $this->getSourceObject();
-        if (!isset(self::$cacheKeyCache[$target])) {
-            self::$cacheKeyCache[$target] = DataList::create($target)->max('LastEdited');
+        if (!isset(TreeDropdownField::$cacheKeyCache[$target])) {
+            TreeDropdownField::$cacheKeyCache[$target] = DataList::create($target)->max('LastEdited');
         }
-        return self::$cacheKeyCache[$target];
+        return TreeDropdownField::$cacheKeyCache[$target];
     }
 
     public function getSchemaDataDefaults()
@@ -917,7 +917,7 @@ public function getSchemaDataDefaults()
 
     /**
      * @param boolean $bool
-     * @return self Self reference
+     * @return TreeDropdownField Self reference
      */
     public function setHasEmptyDefault($bool)
     {
diff --git a/src/ORM/ArrayLib.php b/src/ORM/ArrayLib.php
index 5a03fabee8d..371d0f6dfca 100644
--- a/src/ORM/ArrayLib.php
+++ b/src/ORM/ArrayLib.php
@@ -82,7 +82,7 @@ public static function valuekey($arr)
      */
     public static function array_values_recursive($array)
     {
-        return self::flatten($array, false);
+        return ArrayLib::flatten($array, false);
     }
 
     /**
@@ -146,7 +146,7 @@ public static function in_array_recursive($needle, $haystack, $strict = false)
             return true;
         } else {
             foreach ($haystack as $obj) {
-                if (self::in_array_recursive($needle, $obj, $strict)) {
+                if (ArrayLib::in_array_recursive($needle, $obj, $strict)) {
                     return true;
                 }
             }
diff --git a/src/ORM/Connect/DBQueryBuilder.php b/src/ORM/Connect/DBQueryBuilder.php
index 6a05b41d681..e94c48235d4 100644
--- a/src/ORM/Connect/DBQueryBuilder.php
+++ b/src/ORM/Connect/DBQueryBuilder.php
@@ -98,7 +98,7 @@ protected function buildTraceComment(): string
         // Skip items in the stack trace that originate from these classes or their subclasses,
         // we want to know what called these instead
         $baseClasses = [
-            self::class,
+            DBQueryBuilder::class,
             DataQuery::class,
             SQLExpression::class,
             DB::class,
diff --git a/src/ORM/Connect/Database.php b/src/ORM/Connect/Database.php
index 183aef2a750..6b7dc9c0129 100644
--- a/src/ORM/Connect/Database.php
+++ b/src/ORM/Connect/Database.php
@@ -234,9 +234,9 @@ protected function benchmarkQuery($sql, $callback, $parameters = [])
                 $sql = DB::inline_parameters($sql, $parameters);
             } elseif (strtolower($_REQUEST['showqueries'] ?? '') === 'whitelist') {
                 $displaySql = false;
-                foreach (self::$whitelist_array as $query => $searchType) {
-                    $fullQuery = ($searchType === self::FULL_QUERY && $query === $sql);
-                    $partialQuery = ($searchType === self::PARTIAL_QUERY && mb_strpos($sql ?? '', $query ?? '') !== false);
+                foreach (Database::$whitelist_array as $query => $searchType) {
+                    $fullQuery = ($searchType === Database::FULL_QUERY && $query === $sql);
+                    $partialQuery = ($searchType === Database::PARTIAL_QUERY && mb_strpos($sql ?? '', $query ?? '') !== false);
                     if (!$fullQuery && !$partialQuery) {
                         continue;
                     }
@@ -277,7 +277,7 @@ protected function displayQuery($query, $endtime)
      */
     public static function setWhitelistQueryArray($whitelistArray)
     {
-        self::$whitelist_array = $whitelistArray;
+        Database::$whitelist_array = $whitelistArray;
     }
 
     /**
@@ -287,7 +287,7 @@ public static function setWhitelistQueryArray($whitelistArray)
      */
     public static function getWhitelistQueryArray()
     {
-        return self::$whitelist_array;
+        return Database::$whitelist_array;
     }
 
     /**
diff --git a/src/ORM/Connect/MySQLQueryBuilder.php b/src/ORM/Connect/MySQLQueryBuilder.php
index 755304287d0..dfea806a2cc 100644
--- a/src/ORM/Connect/MySQLQueryBuilder.php
+++ b/src/ORM/Connect/MySQLQueryBuilder.php
@@ -47,7 +47,7 @@ public function buildLimitFragment(SQLSelect $query, array &$parameters)
         }
 
         if ($limit['limit'] === null) {
-            $limit['limit'] = self::MAX_ROWS;
+            $limit['limit'] = MySQLQueryBuilder::MAX_ROWS;
         }
 
         // Format the array limit, given an optional start key
diff --git a/src/ORM/Connect/MySQLSchemaManager.php b/src/ORM/Connect/MySQLSchemaManager.php
index bcab1341368..a4e3cafa8af 100644
--- a/src/ORM/Connect/MySQLSchemaManager.php
+++ b/src/ORM/Connect/MySQLSchemaManager.php
@@ -23,8 +23,8 @@ public function createTable($table, $fields = null, $indexes = null, $options =
     {
         $fieldSchemas = $indexSchemas = "";
 
-        if (!empty($options[self::ID])) {
-            $addOptions = $options[self::ID];
+        if (!empty($options[MySQLSchemaManager::ID])) {
+            $addOptions = $options[MySQLSchemaManager::ID];
         } else {
             $addOptions = "ENGINE=InnoDB";
         }
@@ -97,7 +97,7 @@ public function alterTable(
             }
         }
 
-        $dbID = self::ID;
+        $dbID = MySQLSchemaManager::ID;
         if ($alteredOptions && isset($alteredOptions[$dbID])) {
             $this->query(sprintf("ALTER TABLE \"%s\" %s", $tableName, $alteredOptions[$dbID]));
             $this->alterationMessage(
@@ -232,7 +232,7 @@ private function shouldUseIntegerWidth()
         // MySQL 8.0.17 stopped reporting the width attribute for integers
         // https://github.com/silverstripe/silverstripe-framework/issues/9453
         // Note: MariaDB did not change its behaviour
-        $forceWidth = Config::inst()->get(self::class, 'schema_use_int_width');
+        $forceWidth = Config::inst()->get(MySQLSchemaManager::class, 'schema_use_int_width');
         if ($forceWidth !== null) {
             return $forceWidth;
         }
@@ -256,11 +256,11 @@ public function fieldList($table)
 
             if ($field['Collation'] && $field['Collation'] != 'NULL') {
                 // Cache collation info to cut down on database traffic
-                if (!isset(self::$_cache_collation_info[$field['Collation']])) {
-                    self::$_cache_collation_info[$field['Collation']]
+                if (!isset(MySQLSchemaManager::$_cache_collation_info[$field['Collation']])) {
+                    MySQLSchemaManager::$_cache_collation_info[$field['Collation']]
                         = $this->query("SHOW COLLATION LIKE '{$field['Collation']}'")->record();
                 }
-                $collInfo = self::$_cache_collation_info[$field['Collation']];
+                $collInfo = MySQLSchemaManager::$_cache_collation_info[$field['Collation']];
                 $fieldSpec .= " character set $collInfo[Charset] collate $field[Collation]";
             }
 
diff --git a/src/ORM/Connect/MySQLiConnector.php b/src/ORM/Connect/MySQLiConnector.php
index ca6cad20c46..453746c8fa6 100644
--- a/src/ORM/Connect/MySQLiConnector.php
+++ b/src/ORM/Connect/MySQLiConnector.php
@@ -108,7 +108,7 @@ public function connect($parameters, $selectDB = false)
                 dirname($parameters['ssl_ca'] ?? ''),
                 array_key_exists('ssl_cipher', $parameters ?? [])
                     ? $parameters['ssl_cipher']
-                    : self::config()->get('ssl_cipher_default')
+                    : MySQLiConnector::config()->get('ssl_cipher_default')
             );
         }
 
diff --git a/src/ORM/Connect/NullDatabase.php b/src/ORM/Connect/NullDatabase.php
index 70e5d127787..214998c37e3 100644
--- a/src/ORM/Connect/NullDatabase.php
+++ b/src/ORM/Connect/NullDatabase.php
@@ -34,7 +34,7 @@ class NullDatabase extends Database
     /**
      * @param string $msg
      */
-    public function setErrorMessage(string $msg): self
+    public function setErrorMessage(string $msg): NullDatabase
     {
         $this->errorMessage = $msg;
         return $this;
@@ -43,7 +43,7 @@ public function setErrorMessage(string $msg): self
     /**
      * @param string $msg
      */
-    public function setQueryErrorMessage(string $msg): self
+    public function setQueryErrorMessage(string $msg): NullDatabase
     {
         $this->queryErrorMessage = $msg;
         return $this;
diff --git a/src/ORM/DB.php b/src/ORM/DB.php
index 7be15a65c7c..054b858d02f 100644
--- a/src/ORM/DB.php
+++ b/src/ORM/DB.php
@@ -84,7 +84,7 @@ class DB
      */
     public static function set_conn(Database $connection, $name = 'default')
     {
-        self::$connections[$name] = $connection;
+        DB::$connections[$name] = $connection;
     }
 
     /**
@@ -96,8 +96,8 @@ public static function set_conn(Database $connection, $name = 'default')
      */
     public static function get_conn($name = 'default')
     {
-        if (isset(self::$connections[$name])) {
-            return self::$connections[$name];
+        if (isset(DB::$connections[$name])) {
+            return DB::$connections[$name];
         }
 
         // lazy connect
@@ -118,7 +118,7 @@ public static function get_conn($name = 'default')
      */
     public static function get_schema($name = 'default')
     {
-        $connection = self::get_conn($name);
+        $connection = DB::get_conn($name);
         if ($connection) {
             return $connection->getSchemaManager();
         }
@@ -136,7 +136,7 @@ public static function get_schema($name = 'default')
      */
     public static function build_sql(SQLExpression $expression, &$parameters, $name = 'default')
     {
-        $connection = self::get_conn($name);
+        $connection = DB::get_conn($name);
         if ($connection) {
             return $connection->getQueryBuilder()->buildSQL($expression, $parameters);
         } else {
@@ -154,7 +154,7 @@ public static function build_sql(SQLExpression $expression, &$parameters, $name
      */
     public static function get_connector($name = 'default')
     {
-        $connection = self::get_conn($name);
+        $connection = DB::get_conn($name);
         if ($connection) {
             return $connection->getConnector();
         }
@@ -187,7 +187,7 @@ public static function set_alternative_database_name($name = null)
             return;
         }
         // Validate name
-        if ($name && !self::valid_alternative_database_name($name)) {
+        if ($name && !DB::valid_alternative_database_name($name)) {
             throw new InvalidArgumentException(sprintf(
                 'Invalid alternative database name: "%s"',
                 $name
@@ -200,9 +200,9 @@ public static function set_alternative_database_name($name = null)
         }
         $request = Injector::inst()->get(HTTPRequest::class);
         if ($name) {
-            $request->getSession()->set(self::ALT_DB_KEY, $name);
+            $request->getSession()->set(DB::ALT_DB_KEY, $name);
         } else {
-            $request->getSession()->clear(self::ALT_DB_KEY);
+            $request->getSession()->clear(DB::ALT_DB_KEY);
         }
     }
 
@@ -231,8 +231,8 @@ public static function get_alternative_database_name()
             return null;
         }
 
-        $name = $request->getSession()->get(self::ALT_DB_KEY);
-        if (self::valid_alternative_database_name($name)) {
+        $name = $request->getSession()->get(DB::ALT_DB_KEY);
+        if (DB::valid_alternative_database_name($name)) {
             return $name;
         }
 
@@ -271,7 +271,7 @@ public static function valid_alternative_database_name($name)
     public static function connect($databaseConfig, $label = 'default')
     {
         // This is used by the "testsession" module to test up a test session using an alternative name
-        if ($name = self::get_alternative_database_name()) {
+        if ($name = DB::get_alternative_database_name()) {
             $databaseConfig['database'] = $name;
         }
 
@@ -279,14 +279,14 @@ public static function connect($databaseConfig, $label = 'default')
             throw new InvalidArgumentException("DB::connect: Not passed a valid database config");
         }
 
-        self::$connection_attempted = true;
+        DB::$connection_attempted = true;
 
         $dbClass = $databaseConfig['type'];
 
         // Using Injector->create allows us to use registered configurations
         // which may or may not map to explicit objects
         $conn = Injector::inst()->create($dbClass);
-        self::set_conn($conn, $label);
+        DB::set_conn($conn, $label);
         $conn->connect($databaseConfig);
 
         return $conn;
@@ -323,7 +323,7 @@ public static function getConfig($name = 'default')
      */
     public static function connection_attempted()
     {
-        return self::$connection_attempted;
+        return DB::$connection_attempted;
     }
 
     /**
@@ -334,9 +334,9 @@ public static function connection_attempted()
      */
     public static function query($sql, $errorLevel = E_USER_ERROR)
     {
-        self::$lastQuery = $sql;
+        DB::$lastQuery = $sql;
 
-        return self::get_conn()->query($sql, $errorLevel);
+        return DB::get_conn()->query($sql, $errorLevel);
     }
 
     /**
@@ -426,9 +426,9 @@ public static function inline_parameters($sql, $parameters)
      */
     public static function prepared_query($sql, $parameters, $errorLevel = E_USER_ERROR)
     {
-        self::$lastQuery = $sql;
+        DB::$lastQuery = $sql;
 
-        return self::get_conn()->preparedQuery($sql, $parameters, $errorLevel);
+        return DB::get_conn()->preparedQuery($sql, $parameters, $errorLevel);
     }
 
     /**
@@ -473,8 +473,8 @@ public static function prepared_query($sql, $parameters, $errorLevel = E_USER_ER
      */
     public static function manipulate($manipulation)
     {
-        self::$lastQuery = $manipulation;
-        self::get_conn()->manipulate($manipulation);
+        DB::$lastQuery = $manipulation;
+        DB::get_conn()->manipulate($manipulation);
     }
 
     /**
@@ -485,7 +485,7 @@ public static function manipulate($manipulation)
      */
     public static function get_generated_id($table)
     {
-        return self::get_conn()->getGeneratedID($table);
+        return DB::get_conn()->getGeneratedID($table);
     }
 
     /**
@@ -495,7 +495,7 @@ public static function get_generated_id($table)
      */
     public static function is_active()
     {
-        return ($conn = self::get_conn()) && $conn->isActive();
+        return ($conn = DB::get_conn()) && $conn->isActive();
     }
 
     /**
@@ -508,7 +508,7 @@ public static function is_active()
      */
     public static function create_database($database)
     {
-        return self::get_conn()->selectDatabase($database, true);
+        return DB::get_conn()->selectDatabase($database, true);
     }
 
     /**
@@ -531,7 +531,7 @@ public static function create_table(
         $options = null,
         $advancedOptions = null
     ) {
-        return self::get_schema()->createTable($table, $fields, $indexes, $options, $advancedOptions);
+        return DB::get_schema()->createTable($table, $fields, $indexes, $options, $advancedOptions);
     }
 
     /**
@@ -542,7 +542,7 @@ public static function create_table(
      */
     public static function create_field($table, $field, $spec)
     {
-        return self::get_schema()->createField($table, $field, $spec);
+        return DB::get_schema()->createField($table, $field, $spec);
     }
 
     /**
@@ -568,7 +568,7 @@ public static function require_table(
         $options = null,
         $extensions = null
     ) {
-        self::get_schema()->requireTable($table, $fieldSchema, $indexSchema, $hasAutoIncPK, $options, $extensions);
+        DB::get_schema()->requireTable($table, $fieldSchema, $indexSchema, $hasAutoIncPK, $options, $extensions);
     }
 
     /**
@@ -580,7 +580,7 @@ public static function require_table(
      */
     public static function require_field($table, $field, $spec)
     {
-        self::get_schema()->requireField($table, $field, $spec);
+        DB::get_schema()->requireField($table, $field, $spec);
     }
 
     /**
@@ -592,7 +592,7 @@ public static function require_field($table, $field, $spec)
      */
     public static function require_index($table, $index, $spec)
     {
-        self::get_schema()->requireIndex($table, $index, $spec);
+        DB::get_schema()->requireIndex($table, $index, $spec);
     }
 
     /**
@@ -602,7 +602,7 @@ public static function require_index($table, $index, $spec)
      */
     public static function dont_require_table($table)
     {
-        self::get_schema()->dontRequireTable($table);
+        DB::get_schema()->dontRequireTable($table);
     }
 
     /**
@@ -613,7 +613,7 @@ public static function dont_require_table($table)
      */
     public static function dont_require_field($table, $fieldName)
     {
-        self::get_schema()->dontRequireField($table, $fieldName);
+        DB::get_schema()->dontRequireField($table, $fieldName);
     }
 
     /**
@@ -624,7 +624,7 @@ public static function dont_require_field($table, $fieldName)
      */
     public static function check_and_repair_table($table)
     {
-        return self::get_schema()->checkAndRepairTable($table);
+        return DB::get_schema()->checkAndRepairTable($table);
     }
 
     /**
@@ -634,7 +634,7 @@ public static function check_and_repair_table($table)
      */
     public static function affected_rows()
     {
-        return self::get_conn()->affectedRows();
+        return DB::get_conn()->affectedRows();
     }
 
     /**
@@ -645,7 +645,7 @@ public static function affected_rows()
      */
     public static function table_list()
     {
-        return self::get_schema()->tableList();
+        return DB::get_schema()->tableList();
     }
 
     /**
@@ -657,7 +657,7 @@ public static function table_list()
      */
     public static function field_list($table)
     {
-        return self::get_schema()->fieldList($table);
+        return DB::get_schema()->fieldList($table);
     }
 
     /**
@@ -667,7 +667,7 @@ public static function field_list($table)
      */
     public static function quiet($quiet = true)
     {
-        self::get_schema()->quiet($quiet);
+        DB::get_schema()->quiet($quiet);
     }
 
     /**
@@ -678,6 +678,6 @@ public static function quiet($quiet = true)
      */
     public static function alteration_message($message, $type = "")
     {
-        self::get_schema()->alterationMessage($message, $type);
+        DB::get_schema()->alterationMessage($message, $type);
     }
 }
diff --git a/src/ORM/DataObject.php b/src/ORM/DataObject.php
index 42d0166458a..e57fae5aa3d 100644
--- a/src/ORM/DataObject.php
+++ b/src/ORM/DataObject.php
@@ -339,10 +339,10 @@ class DataObject extends ViewableData implements DataObjectInterface, i18nEntity
      */
     public static function getSchema()
     {
-        if (is_null(self::$schema)) {
-            self::$schema = Injector::inst()->get(DataObjectSchema::class);
+        if (is_null(DataObject::$schema)) {
+            DataObject::$schema = Injector::inst()->get(DataObjectSchema::class);
         }
-        return self::$schema;
+        return DataObject::$schema;
     }
 
     /**
@@ -354,7 +354,7 @@ public static function getSchema()
      *   left as the default by regular users.
      * @param array $queryParams List of DataQuery params necessary to lazy load, or load related objects.
      */
-    public function __construct($record = [], $creationType = self::CREATE_OBJECT, $queryParams = [])
+    public function __construct($record = [], $creationType = DataObject::CREATE_OBJECT, $queryParams = [])
     {
         parent::__construct();
 
@@ -368,7 +368,7 @@ public function __construct($record = [], $creationType = self::CREATE_OBJECT, $
             if (!is_bool($creationType)) {
                 user_error('Creation type is neither boolean (old isSingleton arg) nor integer (new arg), please review your code', E_USER_WARNING);
             }
-            $creationType = $creationType ? self::CREATE_SINGLETON : self::CREATE_OBJECT;
+            $creationType = $creationType ? DataObject::CREATE_SINGLETON : DataObject::CREATE_OBJECT;
         }
 
         // Set query params on the DataObject to tell the lazy loading mechanism the context the object creation context
@@ -379,13 +379,13 @@ public function __construct($record = [], $creationType = self::CREATE_OBJECT, $
 
         switch ($creationType) {
             // Hydrate a record
-            case self::CREATE_HYDRATED:
-            case self::CREATE_MEMORY_HYDRATED:
-                $this->hydrate($record, $creationType === self::CREATE_HYDRATED);
+            case DataObject::CREATE_HYDRATED:
+            case DataObject::CREATE_MEMORY_HYDRATED:
+                $this->hydrate($record, $creationType === DataObject::CREATE_HYDRATED);
                 break;
 
             // Create a new object, using the constructor argument as the initial content
-            case self::CREATE_OBJECT:
+            case DataObject::CREATE_OBJECT:
                 if ($record instanceof stdClass) {
                     $record = (array)$record;
                 }
@@ -425,7 +425,7 @@ public function __construct($record = [], $creationType = self::CREATE_OBJECT, $
                 }
                 break;
 
-            case self::CREATE_SINGLETON:
+            case DataObject::CREATE_SINGLETON:
                 // No setting happens for a singleton
                 $this->record['ID'] = 0;
                 $this->record['ClassName'] = static::class;
@@ -718,7 +718,7 @@ public function getClassName()
     public function setClassName($className)
     {
         $className = trim($className ?? '');
-        if (!$className || !is_subclass_of($className, self::class)) {
+        if (!$className || !is_subclass_of($className, DataObject::class)) {
             return $this;
         }
 
@@ -746,14 +746,14 @@ public function setClassName($className)
      */
     public function newClassInstance($newClassName)
     {
-        if (!is_subclass_of($newClassName, self::class)) {
+        if (!is_subclass_of($newClassName, DataObject::class)) {
             throw new InvalidArgumentException("$newClassName is not a valid subclass of DataObject");
         }
 
         $originalClass = $this->ClassName;
 
         /** @var DataObject $newInstance */
-        $newInstance = Injector::inst()->create($newClassName, $this->record, self::CREATE_MEMORY_HYDRATED);
+        $newInstance = Injector::inst()->create($newClassName, $this->record, DataObject::CREATE_MEMORY_HYDRATED);
 
         // Modify ClassName
         if ($newClassName != $originalClass) {
@@ -773,7 +773,7 @@ public function defineMethods()
     {
         parent::defineMethods();
 
-        if (static::class === self::class) {
+        if (static::class === DataObject::class) {
             return;
         }
 
@@ -1295,7 +1295,7 @@ protected function onAfterDelete()
     }
 
     /**
-     * Load the default values in from the self::$defaults array.
+     * Load the default values in from the DataObject::$defaults array.
      * Will traverse the defaults of the current class and all its parent classes.
      * Called by the constructor when creating new records.
      *
@@ -1331,7 +1331,7 @@ public function populateDefaults()
                     }
                 }
             }
-            if ($class == self::class) {
+            if ($class == DataObject::class) {
                 break;
             }
         }
@@ -1492,7 +1492,7 @@ protected function writeBaseRecord($baseTable, $now)
         $this->prepareManipulationTable($baseTable, $now, true, $manipulation, $this->baseClass());
         DB::manipulate($manipulation);
 
-        $this->changed['ID'] = self::CHANGE_VALUE;
+        $this->changed['ID'] = DataObject::CHANGE_VALUE;
         $this->record['ID'] = DB::get_generated_id($baseTable);
     }
 
@@ -1819,7 +1819,7 @@ public function getComponent($componentName)
             $joinID = $this->getField($joinField);
 
             // Extract class name for polymorphic relations
-            if ($class === self::class) {
+            if ($class === DataObject::class) {
                 $class = $this->getField($componentName . 'Class');
                 if (empty($class)) {
                     return null;
@@ -1902,7 +1902,7 @@ public function setComponent($componentName, $item)
             $this->setField($joinField, $item ? $item->ID : null);
             // Update Class (Polymorphic has_one)
             // Extract class name for polymorphic relations
-            if ($class === self::class) {
+            if ($class === DataObject::class) {
                 $this->setField($componentName . 'Class', $item ? get_class($item) : null);
             }
         } elseif ($class = $schema->belongsToComponent(static::class, $componentName)) {
@@ -2081,7 +2081,7 @@ public function inferReciprocalComponent($remoteClass, $remoteRelation)
             ));
         }
         // If relation is polymorphic, do not infer recriprocal relationship
-        if ($class === self::class) {
+        if ($class === DataObject::class) {
             return null;
         }
         if (!is_a($this, $class ?? '', true)) {
@@ -2444,7 +2444,7 @@ public function scaffoldSearchFields($_params = null)
             if ($fields->fieldByName($generalSearch) || $fields->dataFieldByName($generalSearch)) {
                 throw new LogicException('General search field name must be unique.');
             }
-            $fields->unshift(HiddenField::create($generalSearch, _t(self::class . '.GENERALSEARCH', 'General Search')));
+            $fields->unshift(HiddenField::create($generalSearch, _t(DataObject::class . '.GENERALSEARCH', 'General Search')));
         }
 
         return $fields;
@@ -2742,7 +2742,7 @@ protected function loadLazyFields($class = null)
      * @param int $changeLevel The strictness of what is defined as change. Defaults to strict
      * @return array
      */
-    public function getChangedFields($databaseFieldsOnly = false, $changeLevel = self::CHANGE_STRICT)
+    public function getChangedFields($databaseFieldsOnly = false, $changeLevel = DataObject::CHANGE_STRICT)
     {
         $changedFields = [];
 
@@ -2753,15 +2753,15 @@ public function getChangedFields($databaseFieldsOnly = false, $changeLevel = sel
                 continue;
             }
             if (is_object($v) && method_exists($v, 'isChanged') && $v->isChanged()) {
-                $this->changed[$k] = self::CHANGE_VALUE;
+                $this->changed[$k] = DataObject::CHANGE_VALUE;
             }
         }
 
         // If change was forced, then derive change data from $this->record
-        if ($this->changeForced && $changeLevel <= self::CHANGE_STRICT) {
+        if ($this->changeForced && $changeLevel <= DataObject::CHANGE_STRICT) {
             $changed = array_combine(
                 array_keys($this->record ?? []),
-                array_fill(0, count($this->record ?? []), self::CHANGE_STRICT)
+                array_fill(0, count($this->record ?? []), DataObject::CHANGE_STRICT)
             );
             unset($changed['Version']);
         } else {
@@ -2778,7 +2778,7 @@ public function getChangedFields($databaseFieldsOnly = false, $changeLevel = sel
         }
 
         // Filter the list to those of a certain change level
-        if ($changeLevel > self::CHANGE_STRICT) {
+        if ($changeLevel > DataObject::CHANGE_STRICT) {
             if ($fields) {
                 foreach ($fields as $name => $level) {
                     if ($level < $changeLevel) {
@@ -2809,7 +2809,7 @@ public function getChangedFields($databaseFieldsOnly = false, $changeLevel = sel
      * @param int $changeLevel See {@link getChangedFields()}
      * @return boolean
      */
-    public function isChanged($fieldName = null, $changeLevel = self::CHANGE_STRICT)
+    public function isChanged($fieldName = null, $changeLevel = DataObject::CHANGE_STRICT)
     {
         $fields = $fieldName ? [$fieldName] : true;
         $changed = $this->getChangedFields($fields, $changeLevel);
@@ -2897,13 +2897,13 @@ private function setFieldValue(string $fieldName, mixed $val): void
         // if a field is not existing or has strictly changed
         if (!array_key_exists($fieldName, $this->original ?? []) || $this->original[$fieldName] !== $val) {
             // At the very least, the type has changed
-            $this->changed[$fieldName] = self::CHANGE_STRICT;
+            $this->changed[$fieldName] = DataObject::CHANGE_STRICT;
 
             if ((!array_key_exists($fieldName, $this->original ?? []) && $val)
                 || (array_key_exists($fieldName, $this->original ?? []) && $this->original[$fieldName] != $val)
             ) {
                 // Value has changed as well, not just the type
-                $this->changed[$fieldName] = self::CHANGE_VALUE;
+                $this->changed[$fieldName] = DataObject::CHANGE_VALUE;
             }
         // Value has been restored to its original, remove any record of the change
         } elseif (isset($this->changed[$fieldName])) {
@@ -3298,7 +3298,7 @@ public function getReverseAssociation($className)
      * @param string|array $filter A filter to be inserted into the WHERE clause.
      * Supports parameterised queries. See SQLSelect::addWhere() for syntax examples.
      * @param string|array|null $sort Passed to DataList::sort()
-     * BY clause.  If omitted, self::$default_sort will be used.
+     * BY clause.  If omitted, DataObject::$default_sort will be used.
      * @param string $join Deprecated 3.0 Join clause. Use leftJoin($table, $joinClause) instead.
      * @param string|array $limit A limit expression to be inserted into the LIMIT clause.
      * @param string $containerClass The container class to return the results in.
@@ -3316,14 +3316,14 @@ public static function get(
         // Validate arguments
         if ($callerClass == null) {
             $callerClass = get_called_class();
-            if ($callerClass === self::class) {
+            if ($callerClass === DataObject::class) {
                 throw new InvalidArgumentException('Call <classname>::get() instead of DataObject::get()');
             }
             if ($filter || $sort || $join || $limit || ($containerClass !== DataList::class)) {
                 throw new InvalidArgumentException('If calling <classname>::get() then you shouldn\'t pass any other'
                     . ' arguments');
             }
-        } elseif ($callerClass === self::class) {
+        } elseif ($callerClass === DataObject::class) {
             throw new InvalidArgumentException('DataObject::get() cannot query non-subclass DataObject directly');
         }
         if ($join) {
@@ -3378,7 +3378,7 @@ public static function get_one($callerClass = null, $filter = "", $cache = true,
         }
 
         // Validate class
-        if ($callerClass === self::class) {
+        if ($callerClass === DataObject::class) {
             throw new InvalidArgumentException('DataObject::get_one() cannot query non-subclass DataObject directly');
         }
 
@@ -3389,7 +3389,7 @@ public static function get_one($callerClass = null, $filter = "", $cache = true,
         $cacheKey = md5(serialize($cacheComponents));
 
         $item = null;
-        if (!$cache || !isset(self::$_cache_get_one[$callerClass][$cacheKey])) {
+        if (!$cache || !isset(DataObject::$_cache_get_one[$callerClass][$cacheKey])) {
             $dl = DataObject::get($callerClass);
             if (!empty($filter)) {
                 $dl = $dl->where($filter);
@@ -3400,15 +3400,15 @@ public static function get_one($callerClass = null, $filter = "", $cache = true,
             $item = $dl->first();
 
             if ($cache) {
-                self::$_cache_get_one[$callerClass][$cacheKey] = $item;
-                if (!self::$_cache_get_one[$callerClass][$cacheKey]) {
-                    self::$_cache_get_one[$callerClass][$cacheKey] = false;
+                DataObject::$_cache_get_one[$callerClass][$cacheKey] = $item;
+                if (!DataObject::$_cache_get_one[$callerClass][$cacheKey]) {
+                    DataObject::$_cache_get_one[$callerClass][$cacheKey] = false;
                 }
             }
         }
 
         if ($cache) {
-            return self::$_cache_get_one[$callerClass][$cacheKey] ?: null;
+            return DataObject::$_cache_get_one[$callerClass][$cacheKey] ?: null;
         }
 
         return $item;
@@ -3424,15 +3424,15 @@ public static function get_one($callerClass = null, $filter = "", $cache = true,
      */
     public function flushCache($persistent = true)
     {
-        if (static::class == self::class) {
-            self::$_cache_get_one = [];
+        if (static::class == DataObject::class) {
+            DataObject::$_cache_get_one = [];
             return $this;
         }
 
         $classes = ClassInfo::ancestry(static::class);
         foreach ($classes as $class) {
-            if (isset(self::$_cache_get_one[$class])) {
-                unset(self::$_cache_get_one[$class]);
+            if (isset(DataObject::$_cache_get_one[$class])) {
+                unset(DataObject::$_cache_get_one[$class]);
             }
         }
 
@@ -3448,8 +3448,8 @@ public function flushCache($persistent = true)
      */
     public static function flush_and_destroy_cache()
     {
-        if (self::$_cache_get_one) {
-            foreach (self::$_cache_get_one as $class => $items) {
+        if (DataObject::$_cache_get_one) {
+            foreach (DataObject::$_cache_get_one as $class => $items) {
                 if (is_array($items)) {
                     foreach ($items as $item) {
                         if ($item) {
@@ -3459,7 +3459,7 @@ public static function flush_and_destroy_cache()
                 }
             }
         }
-        self::$_cache_get_one = [];
+        DataObject::$_cache_get_one = [];
     }
 
     /**
@@ -3470,8 +3470,8 @@ public static function reset()
         DBEnum::flushCache();
         ClassInfo::reset_db_cache();
         static::getSchema()->reset();
-        self::$_cache_get_one = [];
-        self::$_cache_field_labels = [];
+        DataObject::$_cache_get_one = [];
+        DataObject::$_cache_field_labels = [];
     }
 
     /**
@@ -3499,7 +3499,7 @@ public static function get_by_id($classOrID, $idOrCache = null, $cache = true)
         }
 
         // Validate class
-        if ($class === self::class) {
+        if ($class === DataObject::class) {
             throw new InvalidArgumentException('DataObject::get_by_id() cannot query non-subclass DataObject directly');
         }
 
@@ -3602,7 +3602,7 @@ public function requireTable()
         $table = $schema->tableName(static::class);
         $fields = $schema->databaseFields(static::class, false);
         $indexes = $schema->databaseIndexes(static::class, false);
-        $extensions = self::database_extensions(static::class);
+        $extensions = DataObject::database_extensions(static::class);
 
         if (empty($table)) {
             throw new LogicException(
@@ -3611,7 +3611,7 @@ public function requireTable()
         }
 
         if ($fields) {
-            $hasAutoIncPK = get_parent_class($this ?? '') === self::class;
+            $hasAutoIncPK = get_parent_class($this ?? '') === DataObject::class;
             DB::require_table(
                 $table,
                 $fields,
@@ -3843,7 +3843,7 @@ public function searchableFields()
      * between data object being required in the search interface.
      *
      * Generates labels based on name of the field itself, if no static property
-     * {@link self::field_labels} exists.
+     * {@link DataObject::field_labels} exists.
      *
      * @uses $field_labels
      * @uses FormField::name_to_label()
@@ -3856,7 +3856,7 @@ public function fieldLabels($includerelations = true)
     {
         $cacheKey = static::class . '_' . $includerelations;
 
-        if (!isset(self::$_cache_field_labels[$cacheKey])) {
+        if (!isset(DataObject::$_cache_field_labels[$cacheKey])) {
             $customLabels = $this->config()->get('field_labels');
             $autoLabels = [];
 
@@ -3902,10 +3902,10 @@ public function fieldLabels($includerelations = true)
 
             $labels = array_merge((array)$autoLabels, (array)$customLabels);
             $this->extend('updateFieldLabels', $labels);
-            self::$_cache_field_labels[$cacheKey] = $labels;
+            DataObject::$_cache_field_labels[$cacheKey] = $labels;
         }
 
-        return self::$_cache_field_labels[$cacheKey];
+        return DataObject::$_cache_field_labels[$cacheKey];
     }
 
     /**
@@ -4024,7 +4024,7 @@ public function isInDB()
     public static function disable_subclass_access()
     {
         Deprecation::notice('5.2.0', 'Will be removed without equivalent functionality');
-        self::$subclass_access = false;
+        DataObject::$subclass_access = false;
     }
 
     /**
@@ -4033,7 +4033,7 @@ public static function disable_subclass_access()
     public static function enable_subclass_access()
     {
         Deprecation::notice('5.2.0', 'Will be removed without equivalent functionality');
-        self::$subclass_access = true;
+        DataObject::$subclass_access = true;
     }
 
     //-------------------------------------------------------------------------------------------//
diff --git a/src/ORM/DataObjectSchema.php b/src/ORM/DataObjectSchema.php
index 6b0acfbce24..9fc2ca6646e 100644
--- a/src/ORM/DataObjectSchema.php
+++ b/src/ORM/DataObjectSchema.php
@@ -206,9 +206,9 @@ public function fieldSpecs($classOrInstance, $options = 0)
         if (!is_int($options)) {
             throw new InvalidArgumentException("Invalid options " . var_export($options, true));
         }
-        $uninherited = ($options & self::UNINHERITED) === self::UNINHERITED;
-        $dbOnly = ($options & self::DB_ONLY) === self::DB_ONLY;
-        $includeClass = ($options & self::INCLUDE_CLASS) === self::INCLUDE_CLASS;
+        $uninherited = ($options & DataObjectSchema::UNINHERITED) === DataObjectSchema::UNINHERITED;
+        $dbOnly = ($options & DataObjectSchema::DB_ONLY) === DataObjectSchema::DB_ONLY;
+        $includeClass = ($options & DataObjectSchema::INCLUDE_CLASS) === DataObjectSchema::INCLUDE_CLASS;
 
         // Walk class hierarchy
         $db = [];
@@ -513,7 +513,7 @@ protected function cacheDatabaseFields($class)
                 }
                 // Handle has_one which handles multiple reciprocal has_many relations
                 $hasOneClass = $spec['class'];
-                if (($spec[self::HAS_ONE_MULTI_RELATIONAL] ?? false) === true) {
+                if (($spec[DataObjectSchema::HAS_ONE_MULTI_RELATIONAL] ?? false) === true) {
                     $compositeFields[$fieldName] = 'PolymorphicRelationAwareForeignKey';
                     continue;
                 }
@@ -577,7 +577,7 @@ protected function cacheDefaultDatabaseIndexes($class)
         }
         $this->defaultDatabaseIndexes[$class] = [];
 
-        $fieldSpecs = $this->fieldSpecs($class, self::UNINHERITED);
+        $fieldSpecs = $this->fieldSpecs($class, DataObjectSchema::UNINHERITED);
         foreach ($fieldSpecs as $field => $spec) {
             /** @var DBField $fieldObj */
             $fieldObj = Injector::inst()->create($spec, $field);
@@ -651,7 +651,7 @@ protected function buildSortDatabaseIndexes($class)
                     list ($table, $column) = $this->parseSortColumn(trim($value ?? ''));
                     $table = trim($table ?? '', '"');
                     $column = trim($column ?? '', '"');
-                    if ($table && strtolower($table ?? '') !== strtolower(self::tableName($class) ?? '')) {
+                    if ($table && strtolower($table ?? '') !== strtolower(DataObjectSchema::tableName($class) ?? '')) {
                         continue;
                     }
                     if ($this->databaseField($class, $column, false)) {
@@ -945,7 +945,7 @@ public function hasOneComponentHandlesMultipleRelations(string $class, string $c
         }
 
         $spec = $hasOnes[$component];
-        return ($spec[self::HAS_ONE_MULTI_RELATIONAL] ?? false) === true;
+        return ($spec[DataObjectSchema::HAS_ONE_MULTI_RELATIONAL] ?? false) === true;
     }
 
     /**
@@ -1280,7 +1280,7 @@ private function checkHasOneArraySpec(string $class, string $component, array $s
             );
         }
 
-        if (($spec[self::HAS_ONE_MULTI_RELATIONAL] ?? false) === true
+        if (($spec[DataObjectSchema::HAS_ONE_MULTI_RELATIONAL] ?? false) === true
             && $spec['class'] !== DataObject::class
         ) {
             throw new InvalidArgumentException(
diff --git a/src/ORM/DataQuery.php b/src/ORM/DataQuery.php
index ef8f6b67b3b..c9230986947 100644
--- a/src/ORM/DataQuery.php
+++ b/src/ORM/DataQuery.php
@@ -743,7 +743,7 @@ public function with(string $name, DataQuery|SQLSelect $query, array $cteFields
         $schema = DataObject::getSchema();
 
         // If the query is a DataQuery, make sure all manipulators, joins, etc are applied
-        if ($query instanceof self) {
+        if ($query instanceof DataQuery) {
             $cteDataClass = $query->dataClass();
             $query = $query->query();
             // DataQuery wants to select ALL columns by default,
diff --git a/src/ORM/EagerLoadedList.php b/src/ORM/EagerLoadedList.php
index 8bec6c948bc..8a53c88905d 100644
--- a/src/ORM/EagerLoadedList.php
+++ b/src/ORM/EagerLoadedList.php
@@ -59,7 +59,7 @@ class EagerLoadedList extends ViewableData implements Relation, SS_List, Filtera
 
     /**
      * Nested eager-loaded data which applies to relations on records contained in this list
-     * @var array<int,self|DataObject>
+     * @var array<int,EagerLoadedList|DataObject>
      */
     private array $eagerLoadedData = [];
 
@@ -148,7 +148,7 @@ private function isValidForeignID(int|array|null $foreignID): bool
      *
      * @return $this
      */
-    public function addEagerLoadedData(string $relation, int $id, self|DataObject $data): static
+    public function addEagerLoadedData(string $relation, int $id, EagerLoadedList|DataObject $data): static
     {
         $this->eagerLoadedData[$id][$relation] = $data;
         return $this;
@@ -856,7 +856,7 @@ public function relation($relationName): ?Relation
                 continue;
             }
             $data = $this->eagerLoadedData[$id][$relationName];
-            if (!($data instanceof self)) {
+            if (!($data instanceof EagerLoadedList)) {
                 // There's no clean way to get the rows back out of DataObject records,
                 // and if it's not a DataObject then we don't know how to handle it,
                 // so fall back to a new DB query
diff --git a/src/ORM/FieldType/DBDate.php b/src/ORM/FieldType/DBDate.php
index b19633d8724..a035d018884 100644
--- a/src/ORM/FieldType/DBDate.php
+++ b/src/ORM/FieldType/DBDate.php
@@ -45,7 +45,7 @@ public function setValue($value, $record = null, $markChanged = true)
         $value = $this->parseDate($value);
         if ($value === false) {
             throw new InvalidArgumentException(
-                "Invalid date: '$value'. Use " . self::ISO_DATE . " to prevent this error."
+                "Invalid date: '$value'. Use " . DBDate::ISO_DATE . " to prevent this error."
             );
         }
         $this->value = $value;
@@ -254,7 +254,7 @@ protected function getInternalFormatter()
      */
     public function getISOFormat()
     {
-        return self::ISO_DATE;
+        return DBDate::ISO_DATE;
     }
 
     /**
@@ -543,7 +543,7 @@ public function InFuture()
      */
     public function IsToday()
     {
-        return $this->Format(self::ISO_DATE) === DBDatetime::now()->Format(self::ISO_DATE);
+        return $this->Format(DBDate::ISO_DATE) === DBDatetime::now()->Format(DBDate::ISO_DATE);
     }
 
     /**
@@ -559,7 +559,7 @@ public function IsToday()
      * @param string $adjustment PHP strtotime style
      * @return $this
      */
-    public function modify(string $adjustment): self
+    public function modify(string $adjustment): DBDate
     {
         $modifiedTime = strtotime($adjustment ?? '', $this->getTimestamp());
         return $this->setValue($modifiedTime);
@@ -572,7 +572,7 @@ public function modify(string $adjustment): self
      */
     public function URLDate()
     {
-        return rawurlencode($this->Format(self::ISO_DATE, self::ISO_LOCALE) ?? '');
+        return rawurlencode($this->Format(DBDate::ISO_DATE, DBDate::ISO_LOCALE) ?? '');
     }
 
     public function scaffoldFormField($title = null, $params = null)
@@ -600,7 +600,7 @@ protected function fixInputDate($value)
         // Validate date
         if (!checkdate($month ?? 0, $day ?? 0, $year ?? 0)) {
             throw new InvalidArgumentException(
-                "Invalid date: '$value'. Use " . self::ISO_DATE . " to prevent this error."
+                "Invalid date: '$value'. Use " . DBDate::ISO_DATE . " to prevent this error."
             );
         }
 
@@ -623,7 +623,7 @@ protected function explodeDateString($value)
             $matches
         )) {
             throw new InvalidArgumentException(
-                "Invalid date: '$value'. Use " . self::ISO_DATE . " to prevent this error."
+                "Invalid date: '$value'. Use " . DBDate::ISO_DATE . " to prevent this error."
             );
         }
 
@@ -638,7 +638,7 @@ protected function explodeDateString($value)
         }
         if ($parts[0] < 1000 && (int)$parts[0] !== 0) {
             throw new InvalidArgumentException(
-                "Invalid date: '$value'. Use " . self::ISO_DATE . " to prevent this error."
+                "Invalid date: '$value'. Use " . DBDate::ISO_DATE . " to prevent this error."
             );
         }
         $parts[] = $matches['time'];
diff --git a/src/ORM/FieldType/DBDatetime.php b/src/ORM/FieldType/DBDatetime.php
index ca3c49e7a7b..877c707f260 100644
--- a/src/ORM/FieldType/DBDatetime.php
+++ b/src/ORM/FieldType/DBDatetime.php
@@ -58,7 +58,7 @@ class DBDatetime extends DBDate implements TemplateGlobalProvider
      * @param bool $immutable
      * @return $this
      */
-    public function setImmutable(bool $immutable): self
+    public function setImmutable(bool $immutable): DBDatetime
     {
         $this->immutable = $immutable;
 
@@ -172,7 +172,7 @@ public function requireField()
      */
     public function URLDatetime()
     {
-        return rawurlencode($this->Format(self::ISO_DATETIME, self::ISO_LOCALE) ?? '');
+        return rawurlencode($this->Format(DBDatetime::ISO_DATETIME, DBDatetime::ISO_LOCALE) ?? '');
     }
 
     public function scaffoldFormField($title = null, $params = null)
@@ -208,7 +208,7 @@ public function scaffoldFormField($title = null, $params = null)
      */
     public static function now()
     {
-        $time = self::$mock_now ? self::$mock_now->Value : time();
+        $time = DBDatetime::$mock_now ? DBDatetime::$mock_now->Value : time();
 
         /** @var DBDatetime $now */
         $now = DBField::create_field('Datetime', $time);
@@ -233,7 +233,7 @@ public static function set_mock_now($datetime)
                 throw new InvalidArgumentException('DBDatetime::set_mock_now(): Wrong format: ' . $value);
             }
         }
-        self::$mock_now = $datetime;
+        DBDatetime::$mock_now = $datetime;
     }
 
     /**
@@ -242,7 +242,7 @@ public static function set_mock_now($datetime)
      */
     public static function clear_mock_now()
     {
-        self::$mock_now = null;
+        DBDatetime::$mock_now = null;
     }
 
     /**
@@ -255,14 +255,14 @@ public static function clear_mock_now()
      */
     public static function withFixedNow($time, $callback)
     {
-        $original = self::$mock_now;
+        $original = DBDatetime::$mock_now;
 
         try {
-            self::set_mock_now($time);
+            DBDatetime::set_mock_now($time);
 
             return $callback();
         } finally {
-            self::$mock_now = $original;
+            DBDatetime::$mock_now = $original;
         }
     }
 
@@ -324,6 +324,6 @@ protected function getInternalFormatter()
      */
     public function getISOFormat()
     {
-        return self::ISO_DATETIME;
+        return DBDatetime::ISO_DATETIME;
     }
 }
diff --git a/src/ORM/FieldType/DBEnum.php b/src/ORM/FieldType/DBEnum.php
index 31df29c462b..b85dec01361 100644
--- a/src/ORM/FieldType/DBEnum.php
+++ b/src/ORM/FieldType/DBEnum.php
@@ -45,7 +45,7 @@ class DBEnum extends DBString
      */
     public static function flushCache()
     {
-        self::$enum_cache = [];
+        DBEnum::$enum_cache = [];
     }
 
     /**
@@ -209,13 +209,13 @@ public function getEnumObsolete()
         }
 
         // Ensure the table level cache exists
-        if (empty(self::$enum_cache[$table])) {
-            self::$enum_cache[$table] = [];
+        if (empty(DBEnum::$enum_cache[$table])) {
+            DBEnum::$enum_cache[$table] = [];
         }
 
         // Check existing cache
-        if (!empty(self::$enum_cache[$table][$name])) {
-            return self::$enum_cache[$table][$name];
+        if (!empty(DBEnum::$enum_cache[$table][$name])) {
+            return DBEnum::$enum_cache[$table][$name];
         }
 
         // Get all enum values
@@ -226,7 +226,7 @@ public function getEnumObsolete()
         }
 
         // Cache and return
-        self::$enum_cache[$table][$name] = $enumValues;
+        DBEnum::$enum_cache[$table][$name] = $enumValues;
         return $enumValues;
     }
 
diff --git a/src/ORM/FieldType/DBField.php b/src/ORM/FieldType/DBField.php
index 079df6b8faf..94b5ee31f15 100644
--- a/src/ORM/FieldType/DBField.php
+++ b/src/ORM/FieldType/DBField.php
@@ -540,7 +540,7 @@ public function saveInto($dataObject)
                 "DBField::saveInto() Called on a nameless '" . static::class . "' object"
             );
         }
-        if ($this->value instanceof self) {
+        if ($this->value instanceof DBField) {
             $this->value->saveInto($dataObject);
         } else {
             $dataObject->__set($fieldName, $this->value);
diff --git a/src/ORM/FieldType/DBForeignKey.php b/src/ORM/FieldType/DBForeignKey.php
index ab23db7489b..befef2b6d79 100644
--- a/src/ORM/FieldType/DBForeignKey.php
+++ b/src/ORM/FieldType/DBForeignKey.php
@@ -77,7 +77,7 @@ public function scaffoldFormField($title = null, $params = null)
         }
         $labelField = $hasOneSingleton->hasField('Title') ? 'Title' : 'Name';
         $list = DataList::create($hasOneClass);
-        $threshold = self::config()->get('dropdown_field_threshold');
+        $threshold = DBForeignKey::config()->get('dropdown_field_threshold');
         $overThreshold = $list->count() > $threshold;
         $field = SearchableDropdownField::create($this->name, $title, $list, $labelField)
             ->setIsLazyLoaded($overThreshold)
diff --git a/src/ORM/FieldType/DBString.php b/src/ORM/FieldType/DBString.php
index 5427aafd930..875936d5650 100644
--- a/src/ORM/FieldType/DBString.php
+++ b/src/ORM/FieldType/DBString.php
@@ -237,6 +237,6 @@ private function addEllipsis(string $string, $add): string
      */
     public function defaultEllipsis(): string
     {
-        return _t(self::class . '.ELLIPSIS', '…');
+        return _t(DBString::class . '.ELLIPSIS', '…');
     }
 }
diff --git a/src/ORM/FieldType/DBTime.php b/src/ORM/FieldType/DBTime.php
index 54c680aef29..6b1813eea5a 100644
--- a/src/ORM/FieldType/DBTime.php
+++ b/src/ORM/FieldType/DBTime.php
@@ -174,7 +174,7 @@ public function FormatFromSettings($member = null)
      */
     public function getISOFormat()
     {
-        return self::ISO_TIME;
+        return DBTime::ISO_TIME;
     }
 
     /**
diff --git a/src/ORM/Filters/SearchFilter.php b/src/ORM/Filters/SearchFilter.php
index daf06f987fd..f622252fbb0 100644
--- a/src/ORM/Filters/SearchFilter.php
+++ b/src/ORM/Filters/SearchFilter.php
@@ -474,7 +474,7 @@ protected function getCaseSensitive()
         } elseif (in_array('nocase', $modifiers ?? [])) {
             return false;
         } else {
-            $sensitive = self::config()->get('default_case_sensitive');
+            $sensitive = SearchFilter::config()->get('default_case_sensitive');
             if ($sensitive !== null) {
                 return $sensitive;
             }
@@ -488,13 +488,13 @@ protected function getCaseSensitive()
      */
     protected function getCaseSensitiveByCollation(): ?bool
     {
-        if (!self::$caseSensitiveByCollation) {
+        if (!SearchFilter::$caseSensitiveByCollation) {
             if (!DB::is_active()) {
                 return null;
             }
-            self::$caseSensitiveByCollation = DB::query("SELECT 'CASE' = 'case'")->record() === 0;
+            SearchFilter::$caseSensitiveByCollation = DB::query("SELECT 'CASE' = 'case'")->record() === 0;
         }
 
-        return self::$caseSensitiveByCollation;
+        return SearchFilter::$caseSensitiveByCollation;
     }
 }
diff --git a/src/ORM/Hierarchy/Hierarchy.php b/src/ORM/Hierarchy/Hierarchy.php
index 41d5411fe86..40adbb8bf2e 100644
--- a/src/ORM/Hierarchy/Hierarchy.php
+++ b/src/ORM/Hierarchy/Hierarchy.php
@@ -298,9 +298,9 @@ public function numChildren($cache = true)
 
         // cached call
         if ($cache) {
-            if (isset(self::$cache_numChildren[$baseClass][$cacheType][$id])) {
-                return self::$cache_numChildren[$baseClass][$cacheType][$id];
-            } elseif (isset(self::$cache_numChildren[$baseClass][$cacheType]['_complete'])) {
+            if (isset(Hierarchy::$cache_numChildren[$baseClass][$cacheType][$id])) {
+                return Hierarchy::$cache_numChildren[$baseClass][$cacheType][$id];
+            } elseif (isset(Hierarchy::$cache_numChildren[$baseClass][$cacheType]['_complete'])) {
                 // If the cache is complete and we didn't find our ID in the cache, it means this object is childless.
                 return 0;
             }
@@ -311,7 +311,7 @@ public function numChildren($cache = true)
 
         // Save if caching
         if ($cache) {
-            self::$cache_numChildren[$baseClass][$cacheType][$id] = $numChildren;
+            Hierarchy::$cache_numChildren[$baseClass][$cacheType][$id] = $numChildren;
         }
 
         return $numChildren;
@@ -333,7 +333,7 @@ public function prepopulateTreeDataCache($recordList = null, array $options = []
         if (empty($options['numChildrenMethod']) || $options['numChildrenMethod'] === 'numChildren') {
             $idList = is_array($recordList) ? $recordList :
                 ($recordList instanceof DataList ? $recordList->column('ID') : null);
-            self::prepopulate_numchildren_cache($this->getHierarchyBaseClass(), $idList);
+            Hierarchy::prepopulate_numchildren_cache($this->getHierarchyBaseClass(), $idList);
         }
 
         $this->owner->extend('onPrepopulateTreeDataCache', $recordList, $options);
@@ -384,11 +384,11 @@ public static function prepopulate_numchildren_cache($baseClass, $idList = null)
         $query->setGroupBy([Convert::symbol2sql("ParentID")]);
 
         $numChildren = $query->execute()->map();
-        self::$cache_numChildren[$baseClass]['numChildren'] = $numChildren;
+        Hierarchy::$cache_numChildren[$baseClass]['numChildren'] = $numChildren;
         if (!$idList) {
             // If all objects are being cached, mark this cache as complete
             // to avoid counting children of childless object.
-            self::$cache_numChildren[$baseClass]['numChildren']['_complete'] = true;
+            Hierarchy::$cache_numChildren[$baseClass]['numChildren']['_complete'] = true;
         }
     }
 
@@ -416,7 +416,7 @@ private function getHierarchyBaseClass(): string
     {
         $ancestry = ClassInfo::ancestry($this->owner);
         $ancestorClass = array_shift($ancestry);
-        while ($ancestorClass && !ViewableData::has_extension($ancestorClass, self::class)) {
+        while ($ancestorClass && !ViewableData::has_extension($ancestorClass, Hierarchy::class)) {
             $ancestorClass = array_shift($ancestry);
         }
 
@@ -575,6 +575,6 @@ public function getBreadcrumbs($separator = ' &raquo; ')
     public function flushCache()
     {
         $this->owner->_cache_children = null;
-        self::$cache_numChildren = [];
+        Hierarchy::$cache_numChildren = [];
     }
 }
diff --git a/src/ORM/Hierarchy/MarkedSet.php b/src/ORM/Hierarchy/MarkedSet.php
index 18dc593fabd..464480c16fd 100644
--- a/src/ORM/Hierarchy/MarkedSet.php
+++ b/src/ORM/Hierarchy/MarkedSet.php
@@ -275,7 +275,7 @@ public function renderChildren(
         if (!$template) {
             $template = [
                 'type' => 'Includes',
-                self::class . '_HTML'
+                MarkedSet::class . '_HTML'
             ];
         }
         $tree = $this->getSubtree($this->rootNode, 0);
diff --git a/src/ORM/ListDecorator.php b/src/ORM/ListDecorator.php
index c7a465a03ad..b063acb7481 100644
--- a/src/ORM/ListDecorator.php
+++ b/src/ORM/ListDecorator.php
@@ -54,7 +54,7 @@ public function getList(): SS_List&Sortable&Filterable&Limitable
      * @param TListA<TA> $list
      * @return static<TListA, TA>
      */
-    public function setList(SS_List&Sortable&Filterable&Limitable $list): self
+    public function setList(SS_List&Sortable&Filterable&Limitable $list): ListDecorator
     {
         $this->list = $list;
         $this->failover = $this->list;
diff --git a/src/ORM/Queries/SQLConditionalExpression.php b/src/ORM/Queries/SQLConditionalExpression.php
index 52a7c0ef24a..20c16c61a5f 100644
--- a/src/ORM/Queries/SQLConditionalExpression.php
+++ b/src/ORM/Queries/SQLConditionalExpression.php
@@ -241,7 +241,7 @@ public function queriedTables()
         foreach ($this->from as $key => $tableClause) {
             if (is_array($tableClause)) {
                 $table = '"' . $tableClause['table'] . '"';
-            } elseif (is_string($tableClause) && preg_match(self::getJoinRegex(), $tableClause ?? '', $matches)) {
+            } elseif (is_string($tableClause) && preg_match(SQLConditionalExpression::getJoinRegex(), $tableClause ?? '', $matches)) {
                 $table = $matches[1];
             } else {
                 $table = $tableClause;
@@ -341,7 +341,7 @@ protected function getOrderedJoins($from)
         // Remove the regular FROM tables out so we only deal with the JOINs
         $regularTables = [];
         foreach ($from as $alias => $tableClause) {
-            if (is_string($tableClause) && !preg_match(self::getJoinRegex(), $tableClause)) {
+            if (is_string($tableClause) && !preg_match(SQLConditionalExpression::getJoinRegex(), $tableClause)) {
                 $regularTables[$alias] = $tableClause;
                 unset($from[$alias]);
             }
diff --git a/src/ORM/Queries/SQLSelect.php b/src/ORM/Queries/SQLSelect.php
index 9ea1591846a..ed0fc4cd197 100644
--- a/src/ORM/Queries/SQLSelect.php
+++ b/src/ORM/Queries/SQLSelect.php
@@ -560,7 +560,7 @@ public function getHavingParameterised(&$parameters)
      */
     public function addUnion(SQLSelect $query, ?string $type = null): static
     {
-        if ($type && $type !== self::UNION_ALL && $type !== self::UNION_DISTINCT) {
+        if ($type && $type !== SQLSelect::UNION_ALL && $type !== SQLSelect::UNION_DISTINCT) {
             throw new LogicException('Union $type must be one of the constants UNION_ALL or UNION_DISTINCT.');
         }
 
diff --git a/src/ORM/Search/FulltextSearchable.php b/src/ORM/Search/FulltextSearchable.php
index 1eeff1fd64b..a4731e593a2 100644
--- a/src/ORM/Search/FulltextSearchable.php
+++ b/src/ORM/Search/FulltextSearchable.php
@@ -77,7 +77,7 @@ public static function enable($searchableClasses = [SiteTree::class, File::class
                 );
             }
         }
-        self::$searchable_classes = $searchableClasses;
+        FulltextSearchable::$searchable_classes = $searchableClasses;
         if (class_exists("SilverStripe\\CMS\\Controllers\\ContentController")) {
             ContentController::add_extension("SilverStripe\\CMS\\Search\\ContentControllerSearchExtension");
         }
@@ -120,6 +120,6 @@ public static function get_extra_config($class, $extensionClass, $args)
      */
     public static function get_searchable_classes()
     {
-        return self::$searchable_classes;
+        return FulltextSearchable::$searchable_classes;
     }
 }
diff --git a/src/ORM/Search/SearchContext.php b/src/ORM/Search/SearchContext.php
index 7cd78233177..0c6834353e7 100644
--- a/src/ORM/Search/SearchContext.php
+++ b/src/ORM/Search/SearchContext.php
@@ -81,7 +81,7 @@ class SearchContext
 
     /**
      * A key value pair of values that should be searched for.
-     * The keys should match the field names specified in {@link self::$fields}.
+     * The keys should match the field names specified in {@link SearchContext::$fields}.
      * Usually these values come from a submitted searchform
      * in the form of a $_REQUEST object.
      * CAUTION: All values should be treated as insecure client input.
diff --git a/src/ORM/ValidationResult.php b/src/ORM/ValidationResult.php
index 6d45996d5b7..8ba3ba545ba 100644
--- a/src/ORM/ValidationResult.php
+++ b/src/ORM/ValidationResult.php
@@ -73,7 +73,7 @@ class ValidationResult
      * Bool values will be treated as plain text flag.
      * @return $this
      */
-    public function addError($message, $messageType = self::TYPE_ERROR, $code = null, $cast = self::CAST_TEXT)
+    public function addError($message, $messageType = ValidationResult::TYPE_ERROR, $code = null, $cast = ValidationResult::CAST_TEXT)
     {
         return $this->addFieldError(null, $message, $messageType, $code, $cast);
     }
@@ -94,9 +94,9 @@ public function addError($message, $messageType = self::TYPE_ERROR, $code = null
     public function addFieldError(
         $fieldName,
         $message,
-        $messageType = self::TYPE_ERROR,
+        $messageType = ValidationResult::TYPE_ERROR,
         $code = null,
-        $cast = self::CAST_TEXT
+        $cast = ValidationResult::CAST_TEXT
     ) {
         $this->isValid = false;
         return $this->addFieldMessage($fieldName, $message, $messageType, $code, $cast);
@@ -114,7 +114,7 @@ public function addFieldError(
      * Bool values will be treated as plain text flag.
      * @return $this
      */
-    public function addMessage($message, $messageType = self::TYPE_ERROR, $code = null, $cast = self::CAST_TEXT)
+    public function addMessage($message, $messageType = ValidationResult::TYPE_ERROR, $code = null, $cast = ValidationResult::CAST_TEXT)
     {
         return $this->addFieldMessage(null, $message, $messageType, $code, $cast);
     }
@@ -135,15 +135,15 @@ public function addMessage($message, $messageType = self::TYPE_ERROR, $code = nu
     public function addFieldMessage(
         $fieldName,
         $message,
-        $messageType = self::TYPE_ERROR,
+        $messageType = ValidationResult::TYPE_ERROR,
         $code = null,
-        $cast = self::CAST_TEXT
+        $cast = ValidationResult::CAST_TEXT
     ) {
         if ($code && is_numeric($code)) {
             throw new InvalidArgumentException("Don't use a numeric code '$code'.  Use a string.");
         }
         if (is_bool($cast)) {
-            $cast = $cast ? self::CAST_TEXT : self::CAST_HTML;
+            $cast = $cast ? ValidationResult::CAST_TEXT : ValidationResult::CAST_HTML;
         }
         $metadata = [
             'message' => $message,
diff --git a/src/Security/BasicAuth.php b/src/Security/BasicAuth.php
index 9c47c1f1d6c..d99d7802d90 100644
--- a/src/Security/BasicAuth.php
+++ b/src/Security/BasicAuth.php
@@ -43,7 +43,7 @@ class BasicAuth
 
     /**
      * @config
-     * @var Boolean Flag set by {@link self::protect_entire_site()}
+     * @var Boolean Flag set by {@link BasicAuth::protect_entire_site()}
      */
     private static $entire_site_protected = false;
 
@@ -187,7 +187,7 @@ public static function requireLogin(
      *  of the permission codes a user has.
      * @param string $message
      */
-    public static function protect_entire_site($protect = true, $code = self::AUTH_PERMISSION, $message = null)
+    public static function protect_entire_site($protect = true, $code = BasicAuth::AUTH_PERMISSION, $message = null)
     {
         static::config()
             ->set('entire_site_protected', $protect)
@@ -214,11 +214,11 @@ public static function protect_site_if_necessary(HTTPRequest $request = null)
         // Check if site is protected
         if ($config->get('entire_site_protected')) {
             $permissionCode = $config->get('entire_site_protected_code');
-        } elseif (Environment::getEnv(self::USE_BASIC_AUTH)) {
+        } elseif (Environment::getEnv(BasicAuth::USE_BASIC_AUTH)) {
             // Convert legacy 1 / true to ADMIN permissions
-            $permissionCode = Environment::getEnv(self::USE_BASIC_AUTH);
+            $permissionCode = Environment::getEnv(BasicAuth::USE_BASIC_AUTH);
             if (!is_string($permissionCode) || is_numeric($permissionCode)) {
-                $permissionCode = self::AUTH_PERMISSION;
+                $permissionCode = BasicAuth::AUTH_PERMISSION;
             }
         } else {
             // Not enabled
diff --git a/src/Security/Confirmation/Storage.php b/src/Security/Confirmation/Storage.php
index ef4e01720fa..01f82239805 100644
--- a/src/Security/Confirmation/Storage.php
+++ b/src/Security/Confirmation/Storage.php
@@ -368,7 +368,7 @@ public function setSuccessUrl($url)
     }
 
     /**
-     * Returns the URL registered by {@see self::setSuccessUrl} as a success redirect target
+     * Returns the URL registered by {@see Storage::setSuccessUrl} as a success redirect target
      *
      * @return string
      */
@@ -391,7 +391,7 @@ public function setFailureUrl($url)
     }
 
     /**
-     * Returns the URL registered by {@see self::setFailureUrl} as a success redirect target
+     * Returns the URL registered by {@see Storage::setFailureUrl} as a success redirect target
      *
      * @return string
      */
diff --git a/src/Security/InheritedPermissions.php b/src/Security/InheritedPermissions.php
index bcaa1f6b654..65b66044819 100644
--- a/src/Security/InheritedPermissions.php
+++ b/src/Security/InheritedPermissions.php
@@ -147,7 +147,7 @@ public function flushMemberCache($memberIDs = null)
         }
 
         if ($memberIDs && is_array($memberIDs)) {
-            foreach ([self::VIEW, self::EDIT, self::DELETE] as $type) {
+            foreach ([InheritedPermissions::VIEW, InheritedPermissions::EDIT, InheritedPermissions::DELETE] as $type) {
                 foreach ($memberIDs as $memberID) {
                     $key = $this->generateCacheKey($type, $memberID);
                     $this->cacheService->delete($key);
@@ -215,13 +215,13 @@ public function getBaseClass()
     public function prePopulatePermissionCache($permission = 'edit', $ids = [])
     {
         switch ($permission) {
-            case self::EDIT:
+            case InheritedPermissions::EDIT:
                 $this->canEditMultiple($ids, Security::getCurrentUser(), false);
                 break;
-            case self::VIEW:
+            case InheritedPermissions::VIEW:
                 $this->canViewMultiple($ids, Security::getCurrentUser(), false);
                 break;
-            case self::DELETE:
+            case InheritedPermissions::DELETE:
                 $this->canDeleteMultiple($ids, Security::getCurrentUser(), false);
                 break;
             default:
@@ -265,7 +265,7 @@ protected function batchPermissionCheck(
         // Validate member permission
         // Only VIEW allows anonymous (Anyone) permissions
         $memberID = $member ? (int)$member->ID : 0;
-        if (!$memberID && $type !== self::VIEW) {
+        if (!$memberID && $type !== InheritedPermissions::VIEW) {
             return $result;
         }
 
@@ -374,10 +374,10 @@ protected function batchPermissionCheckForStage(
                         . " OR (\"$typeField\" = ? AND \"$memberJoinTable\".\"{$baseTable}ID\" IS NOT NULL)"
                         . ")"
                         => [
-                            self::ANYONE,
-                            self::LOGGED_IN_USERS,
-                            self::ONLY_THESE_USERS,
-                            self::ONLY_THESE_MEMBERS,
+                            InheritedPermissions::ANYONE,
+                            InheritedPermissions::LOGGED_IN_USERS,
+                            InheritedPermissions::ONLY_THESE_USERS,
+                            InheritedPermissions::ONLY_THESE_MEMBERS,
                         ]
                     ])
                     ->leftJoin(
@@ -393,7 +393,7 @@ protected function batchPermissionCheckForStage(
         } else {
             // Only view pages with ViewType = Anyone if not logged in
             $uninheritedPermissions = $stageRecords
-                ->filter($typeField, self::ANYONE)
+                ->filter($typeField, InheritedPermissions::ANYONE)
                 ->column('ID');
         }
 
@@ -406,7 +406,7 @@ protected function batchPermissionCheckForStage(
         // We group these and run a batch permission check on all parents. This gives us the result
         // of whether the user has permission to edit this object.
         $groupedByParent = [];
-        $potentiallyInherited = $stageRecords->filter($typeField, self::INHERIT)
+        $potentiallyInherited = $stageRecords->filter($typeField, InheritedPermissions::INHERIT)
             ->orderBy("\"{$baseTable}\".\"ID\"")
             ->dataQuery()
             ->query()
@@ -456,7 +456,7 @@ protected function batchPermissionCheckForStage(
     public function canEditMultiple($ids, Member $member = null, $useCached = true)
     {
         return $this->batchPermissionCheck(
-            self::EDIT,
+            InheritedPermissions::EDIT,
             $ids,
             $member,
             $this->getGlobalEditPermissions(),
@@ -472,7 +472,7 @@ public function canEditMultiple($ids, Member $member = null, $useCached = true)
      */
     public function canViewMultiple($ids, Member $member = null, $useCached = true)
     {
-        return $this->batchPermissionCheck(self::VIEW, $ids, $member, [], $useCached);
+        return $this->batchPermissionCheck(InheritedPermissions::VIEW, $ids, $member, [], $useCached);
     }
 
     /**
@@ -559,7 +559,7 @@ public function canDelete($id, Member $member = null)
     {
         // No ID: Check default permission
         if (!$id) {
-            return $this->checkDefaultPermissions(self::DELETE, $member);
+            return $this->checkDefaultPermissions(InheritedPermissions::DELETE, $member);
         }
 
         // Regular canEdit logic is handled by canEditMultiple
@@ -581,7 +581,7 @@ public function canEdit($id, Member $member = null)
     {
         // No ID: Check default permission
         if (!$id) {
-            return $this->checkDefaultPermissions(self::EDIT, $member);
+            return $this->checkDefaultPermissions(InheritedPermissions::EDIT, $member);
         }
 
         // Regular canEdit logic is handled by canEditMultiple
@@ -603,7 +603,7 @@ public function canView($id, Member $member = null)
     {
         // No ID: Check default permission
         if (!$id) {
-            return $this->checkDefaultPermissions(self::VIEW, $member);
+            return $this->checkDefaultPermissions(InheritedPermissions::VIEW, $member);
         }
 
         // Regular canView logic is handled by canViewMultiple
@@ -626,11 +626,11 @@ public function canView($id, Member $member = null)
     protected function getPermissionField($type)
     {
         switch ($type) {
-            case self::DELETE:
+            case InheritedPermissions::DELETE:
                 // Delete uses edit type - Drop through
-            case self::EDIT:
+            case InheritedPermissions::EDIT:
                 return 'CanEditType';
-            case self::VIEW:
+            case InheritedPermissions::VIEW:
                 return 'CanViewType';
             default:
                 throw new InvalidArgumentException("Invalid argument type $type");
@@ -661,11 +661,11 @@ protected function getJoinTable($type)
     protected function getGroupJoinTable($type)
     {
         switch ($type) {
-            case self::DELETE:
+            case InheritedPermissions::DELETE:
                 // Delete uses edit type - Drop through
-            case self::EDIT:
+            case InheritedPermissions::EDIT:
                 return $this->getEditorGroupsTable();
-            case self::VIEW:
+            case InheritedPermissions::VIEW:
                 return $this->getViewerGroupsTable();
             default:
                 throw new InvalidArgumentException("Invalid argument type $type");
@@ -682,11 +682,11 @@ protected function getGroupJoinTable($type)
     protected function getMemberJoinTable($type)
     {
         switch ($type) {
-            case self::DELETE:
+            case InheritedPermissions::DELETE:
                 // Delete uses edit type - Drop through
-            case self::EDIT:
+            case InheritedPermissions::EDIT:
                 return $this->getEditorMembersTable();
-            case self::VIEW:
+            case InheritedPermissions::VIEW:
                 return $this->getViewerMembersTable();
             default:
                 throw new InvalidArgumentException("Invalid argument type $type");
@@ -707,11 +707,11 @@ protected function checkDefaultPermissions($type, Member $member = null)
             return false;
         }
         switch ($type) {
-            case self::VIEW:
+            case InheritedPermissions::VIEW:
                 return $defaultPermissions->canView($member);
-            case self::EDIT:
+            case InheritedPermissions::EDIT:
                 return $defaultPermissions->canEdit($member);
-            case self::DELETE:
+            case InheritedPermissions::DELETE:
                 return $defaultPermissions->canDelete($member);
             default:
                 return false;
diff --git a/src/Security/LogoutForm.php b/src/Security/LogoutForm.php
index e8851c51e07..03ad3a05965 100644
--- a/src/Security/LogoutForm.php
+++ b/src/Security/LogoutForm.php
@@ -23,7 +23,7 @@ class LogoutForm extends Form
      */
     public function __construct(
         RequestHandler $controller = null,
-        $name = self::DEFAULT_NAME,
+        $name = LogoutForm::DEFAULT_NAME,
         FieldList $fields = null,
         FieldList $actions = null,
         Validator $validator = null
diff --git a/src/Security/Member.php b/src/Security/Member.php
index 446ca658888..0ae8b37d07d 100644
--- a/src/Security/Member.php
+++ b/src/Security/Member.php
@@ -478,7 +478,7 @@ public function afterMemberLoggedIn()
     public function regenerateTempID()
     {
         $generator = new RandomGenerator();
-        $lifetime = self::config()->get('temp_id_lifetime');
+        $lifetime = Member::config()->get('temp_id_lifetime');
         $this->TempIDHash = $generator->randomToken('sha1');
         $this->TempIDExpired = $lifetime
             ? date('Y-m-d H:i:s', strtotime(DBDatetime::now()->getValue()) + $lifetime)
@@ -565,7 +565,7 @@ public function generateAutologinTokenAndStoreHash()
     public function validateAutoLoginToken($autologinToken)
     {
         $hash = $this->encryptWithUserSettings($autologinToken);
-        $member = self::member_from_autologinhash($hash, false);
+        $member = Member::member_from_autologinhash($hash, false);
 
         return (bool)$member;
     }
@@ -1615,7 +1615,7 @@ public function changePassword($password, $write = true)
     protected function encryptPassword()
     {
         // reset salt so that it gets regenerated - this will invalidate any persistent login cookies
-        // or other information encrypted with this Member's settings (see self::encryptWithUserSettings)
+        // or other information encrypted with this Member's settings (see Member::encryptWithUserSettings)
         $this->Salt = '';
 
         // Password was changed: encrypt the password according the settings
@@ -1650,13 +1650,13 @@ protected function encryptPassword()
      */
     public function registerFailedLogin()
     {
-        $lockOutAfterCount = self::config()->get('lock_out_after_incorrect_logins');
+        $lockOutAfterCount = Member::config()->get('lock_out_after_incorrect_logins');
         if ($lockOutAfterCount) {
             // Keep a tally of the number of failed log-ins so that we can lock people out
             ++$this->FailedLoginCount;
 
             if ($this->FailedLoginCount >= $lockOutAfterCount) {
-                $lockoutMins = self::config()->get('lock_out_delay_mins');
+                $lockoutMins = Member::config()->get('lock_out_delay_mins');
                 $this->LockedOutUntil = date('Y-m-d H:i:s', DBDatetime::now()->getTimestamp() + $lockoutMins * 60);
                 $this->FailedLoginCount = 0;
             }
@@ -1670,7 +1670,7 @@ public function registerFailedLogin()
      */
     public function registerSuccessfulLogin()
     {
-        if (self::config()->get('lock_out_after_incorrect_logins')) {
+        if (Member::config()->get('lock_out_after_incorrect_logins')) {
             // Forgive all past login failures
             $this->FailedLoginCount = 0;
             $this->LockedOutUntil = null;
@@ -1714,7 +1714,7 @@ public function getHtmlEditorConfigForCMS()
     public function generateRandomPassword(int $length = 0): string
     {
         $password = '';
-        $validator = self::password_validator();
+        $validator = Member::password_validator();
         if ($length && $validator && $length < $validator->getMinLength()) {
             throw new InvalidArgumentException('length argument is less than password validator minLength');
         }
diff --git a/src/Security/MemberAuthenticator/MemberLoginForm.php b/src/Security/MemberAuthenticator/MemberLoginForm.php
index 94dd5027d1c..4111b3d4b8b 100644
--- a/src/Security/MemberAuthenticator/MemberLoginForm.php
+++ b/src/Security/MemberAuthenticator/MemberLoginForm.php
@@ -111,7 +111,7 @@ public function __construct(
         if (isset($logoutAction)) {
             $this->setFormAction($logoutAction);
         }
-        $this->setValidator(RequiredFields::create(self::config()->get('required_fields')));
+        $this->setValidator(RequiredFields::create(MemberLoginForm::config()->get('required_fields')));
     }
 
     /**
@@ -225,6 +225,6 @@ public function restoreFormState()
      */
     public function getAuthenticatorName()
     {
-        return _t(self::class . '.AUTHENTICATORNAME', "E-mail & Password");
+        return _t(MemberLoginForm::class . '.AUTHENTICATORNAME', "E-mail & Password");
     }
 }
diff --git a/src/Security/PasswordEncryptor.php b/src/Security/PasswordEncryptor.php
index 56e42af7f78..cbf6484877b 100644
--- a/src/Security/PasswordEncryptor.php
+++ b/src/Security/PasswordEncryptor.php
@@ -28,7 +28,7 @@ abstract class PasswordEncryptor
      */
     public static function get_encryptors()
     {
-        return Config::inst()->get(self::class, 'encryptors');
+        return Config::inst()->get(PasswordEncryptor::class, 'encryptors');
     }
 
     /**
@@ -38,7 +38,7 @@ public static function get_encryptors()
      */
     public static function create_for_algorithm($algorithm)
     {
-        $encryptors = self::get_encryptors();
+        $encryptors = PasswordEncryptor::get_encryptors();
         if (!isset($encryptors[$algorithm])) {
             throw new PasswordEncryptor_NotFoundException(
                 sprintf('No implementation found for "%s"', $algorithm)
diff --git a/src/Security/PasswordEncryptor_Blowfish.php b/src/Security/PasswordEncryptor_Blowfish.php
index 877fdd1247b..0b6277d8f3f 100644
--- a/src/Security/PasswordEncryptor_Blowfish.php
+++ b/src/Security/PasswordEncryptor_Blowfish.php
@@ -30,7 +30,7 @@ class PasswordEncryptor_Blowfish extends PasswordEncryptor
      */
     public static function set_cost($cost)
     {
-        self::$cost = max(min(31, $cost), 4);
+        PasswordEncryptor_Blowfish::$cost = max(min(31, $cost), 4);
     }
 
     /**
@@ -40,7 +40,7 @@ public static function set_cost($cost)
      */
     public static function get_cost()
     {
-        return self::$cost;
+        return PasswordEncryptor_Blowfish::$cost;
     }
 
     public function encrypt($password, $salt = null, $member = null)
@@ -153,7 +153,7 @@ public function checkAEncryptionLevel()
     }
 
     /**
-     * self::$cost param is forced to be two digits with leading zeroes for ints 4-9
+     * PasswordEncryptor_Blowfish::$cost param is forced to be two digits with leading zeroes for ints 4-9
      *
      * @param string $password
      * @param Member $member
@@ -162,7 +162,7 @@ public function checkAEncryptionLevel()
     public function salt($password, $member = null)
     {
         $generator = new RandomGenerator();
-        return sprintf('%02d', self::$cost) . '$' . substr($generator->randomToken('sha1') ?? '', 0, 22);
+        return sprintf('%02d', PasswordEncryptor_Blowfish::$cost) . '$' . substr($generator->randomToken('sha1') ?? '', 0, 22);
     }
 
     public function check($hash, $password, $salt = null, $member = null)
diff --git a/src/Security/Permission.php b/src/Security/Permission.php
index c15757f575a..ce57f81bbf3 100644
--- a/src/Security/Permission.php
+++ b/src/Security/Permission.php
@@ -122,7 +122,7 @@ public static function check($code, $arg = "any", $member = null, $strict = true
             $member = Security::getCurrentUser();
         }
 
-        return self::checkMember($member, $code, $arg, $strict);
+        return Permission::checkMember($member, $code, $arg, $strict);
     }
 
     /**
@@ -136,7 +136,7 @@ public static function check($code, $arg = "any", $member = null, $strict = true
      */
     public static function reset()
     {
-        self::$cache_permissions = [];
+        Permission::$cache_permissions = [];
     }
 
     /**
@@ -173,12 +173,12 @@ public static function checkMember($member, $code, $arg = "any", $strict = true)
 
         if ($arg == 'any') {
             // Cache the permissions in memory
-            if (!isset(self::$cache_permissions[$memberID])) {
-                self::$cache_permissions[$memberID] = self::permissions_for_member($memberID);
+            if (!isset(Permission::$cache_permissions[$memberID])) {
+                Permission::$cache_permissions[$memberID] = Permission::permissions_for_member($memberID);
             }
             foreach ($code as $permCode) {
                 if ($permCode === 'CMS_ACCESS') {
-                    foreach (self::$cache_permissions[$memberID] as $perm) {
+                    foreach (Permission::$cache_permissions[$memberID] as $perm) {
                         //if they have admin rights OR they have an explicit access to the CMS then give permission
                         if (($adminImpliesAll && $perm == 'ADMIN') || substr($perm ?? '', 0, 11) === 'CMS_ACCESS_') {
                             return true;
@@ -196,7 +196,7 @@ public static function checkMember($member, $code, $arg = "any", $strict = true)
             }
 
             // Multiple $code values - return true if at least one matches, ie, intersection exists
-            return (bool)array_intersect($code ?? [], self::$cache_permissions[$memberID]);
+            return (bool)array_intersect($code ?? [], Permission::$cache_permissions[$memberID]);
         }
 
         // Code filters
@@ -207,7 +207,7 @@ public static function checkMember($member, $code, $arg = "any", $strict = true)
 
         // The following code should only be used if you're not using the "any" arg.  This is kind
         // of obsolete functionality and could possibly be deprecated.
-        $groupParams = self::groupList($memberID);
+        $groupParams = Permission::groupList($memberID);
         if (empty($groupParams)) {
             return false;
         }
@@ -245,7 +245,7 @@ public static function checkMember($member, $code, $arg = "any", $strict = true)
             array_merge(
                 $codeParams,
                 $adminParams,
-                [self::GRANT_PERMISSION],
+                [Permission::GRANT_PERMISSION],
                 $groupParams,
                 $argParams
             )
@@ -264,7 +264,7 @@ public static function checkMember($member, $code, $arg = "any", $strict = true)
 					\"Code\" IN ($codeClause) AND
 					\"Type\" = ?
 				)",
-                array_merge($codeParams, [self::GRANT_PERMISSION])
+                array_merge($codeParams, [Permission::GRANT_PERMISSION])
             )->value();
 
             if (!$hasPermission) {
@@ -283,7 +283,7 @@ public static function checkMember($member, $code, $arg = "any", $strict = true)
      */
     public static function permissions_for_member($memberID)
     {
-        $groupList = self::groupList($memberID);
+        $groupList = Permission::groupList($memberID);
 
         if ($groupList) {
             $groupCSV = implode(", ", $groupList);
@@ -291,7 +291,7 @@ public static function permissions_for_member($memberID)
             $allowed = array_unique(DB::query("
 				SELECT \"Code\"
 				FROM \"Permission\"
-				WHERE \"Type\" = " . self::GRANT_PERMISSION . " AND \"GroupID\" IN ($groupCSV)
+				WHERE \"Type\" = " . Permission::GRANT_PERMISSION . " AND \"GroupID\" IN ($groupCSV)
 
 				UNION
 
@@ -305,7 +305,7 @@ public static function permissions_for_member($memberID)
             $denied = array_unique(DB::query("
 				SELECT \"Code\"
 				FROM \"Permission\"
-				WHERE \"Type\" = " . self::DENY_PERMISSION . " AND \"GroupID\" IN ($groupCSV)
+				WHERE \"Type\" = " . Permission::DENY_PERMISSION . " AND \"GroupID\" IN ($groupCSV)
 			")->column() ?? []);
 
             return array_diff($allowed ?? [], $denied);
@@ -384,7 +384,7 @@ public static function grant($groupID, $code, $arg = "any")
             $perm->Code = $code;
         }
 
-        $perm->Type = self::GRANT_PERMISSION;
+        $perm->Type = Permission::GRANT_PERMISSION;
 
         // Arg component
         switch ($arg) {
@@ -426,7 +426,7 @@ public static function deny($groupID, $code, $arg = "any")
             $perm->Code = $code;
         }
 
-        $perm->Type = self::DENY_PERMISSION;
+        $perm->Type = Permission::DENY_PERMISSION;
 
         // Arg component
         switch ($arg) {
@@ -456,7 +456,7 @@ public static function deny($groupID, $code, $arg = "any")
      */
     public static function get_members_by_permission($code)
     {
-        $toplevelGroups = self::get_groups_by_permission($code);
+        $toplevelGroups = Permission::get_groups_by_permission($code);
         if (!$toplevelGroups) {
             return new ArrayList();
         }
diff --git a/src/Security/RememberLoginHash.php b/src/Security/RememberLoginHash.php
index 27f9f345bad..389afcebded 100644
--- a/src/Security/RememberLoginHash.php
+++ b/src/Security/RememberLoginHash.php
@@ -217,9 +217,9 @@ public static function clear(Member $member, $alcDevice = null)
         }
 
         if (static::getLogoutAcrossDevices()) {
-            self::get()->filter(['MemberID' => $member->ID])->removeAll();
+            RememberLoginHash::get()->filter(['MemberID' => $member->ID])->removeAll();
         } elseif ($alcDevice) {
-            self::get()->filter([
+            RememberLoginHash::get()->filter([
                 'MemberID' => $member->ID,
                 'DeviceID' => $alcDevice
             ])->removeAll();
diff --git a/src/Security/Security.php b/src/Security/Security.php
index eea203ba479..fd3657a8b6d 100644
--- a/src/Security/Security.php
+++ b/src/Security/Security.php
@@ -306,7 +306,7 @@ public function hasAuthenticator($authenticator)
      */
     public static function permissionFailure($controller = null, $messageSet = null): HTTPResponse
     {
-        self::set_ignore_disallowed_actions(true);
+        Security::set_ignore_disallowed_actions(true);
 
         // Parse raw message / escape type
         $parseMessage = function ($message) {
@@ -437,7 +437,7 @@ public static function permissionFailure($controller = null, $messageSet = null)
      */
     public static function setCurrentUser($currentUser = null)
     {
-        self::$currentUser = $currentUser;
+        Security::$currentUser = $currentUser;
     }
 
     /**
@@ -445,7 +445,7 @@ public static function setCurrentUser($currentUser = null)
      */
     public static function getCurrentUser()
     {
-        return self::$currentUser;
+        return Security::$currentUser;
     }
 
     /**
@@ -1049,7 +1049,7 @@ public static function encrypt_password($password, $salt = null, $algorithm = nu
     {
         // Fall back to the default encryption algorithm
         if (!$algorithm) {
-            $algorithm = self::config()->get('password_encryption_algorithm');
+            $algorithm = Security::config()->get('password_encryption_algorithm');
         }
 
         $encryptor = PasswordEncryptor::create_for_algorithm($algorithm);
@@ -1074,12 +1074,12 @@ public static function encrypt_password($password, $salt = null, $algorithm = nu
     public static function database_is_ready()
     {
         // Used for unit tests
-        if (self::$force_database_is_ready !== null) {
-            return self::$force_database_is_ready;
+        if (Security::$force_database_is_ready !== null) {
+            return Security::$force_database_is_ready;
         }
 
-        if (self::$database_is_ready) {
-            return self::$database_is_ready;
+        if (Security::$database_is_ready) {
+            return Security::$database_is_ready;
         }
 
         $requiredClasses = ClassInfo::dataClassesFor(Member::class);
@@ -1115,7 +1115,7 @@ public static function database_is_ready()
                 return false;
             }
         }
-        self::$database_is_ready = true;
+        Security::$database_is_ready = true;
 
         return true;
     }
@@ -1125,8 +1125,8 @@ public static function database_is_ready()
      */
     public static function clear_database_is_ready()
     {
-        self::$database_is_ready = null;
-        self::$force_database_is_ready = null;
+        Security::$database_is_ready = null;
+        Security::$force_database_is_ready = null;
     }
 
     /**
@@ -1136,7 +1136,7 @@ public static function clear_database_is_ready()
      */
     public static function force_database_is_ready($isReady)
     {
-        self::$force_database_is_ready = $isReady;
+        Security::$force_database_is_ready = $isReady;
     }
 
     /**
@@ -1165,12 +1165,12 @@ public static function force_database_is_ready($isReady)
      */
     public static function set_ignore_disallowed_actions($flag)
     {
-        self::$ignore_disallowed_actions = $flag;
+        Security::$ignore_disallowed_actions = $flag;
     }
 
     public static function ignore_disallowed_actions()
     {
-        return self::$ignore_disallowed_actions;
+        return Security::$ignore_disallowed_actions;
     }
 
     /**
@@ -1182,7 +1182,7 @@ public static function ignore_disallowed_actions()
      */
     public static function login_url()
     {
-        return Controller::join_links(Director::baseURL(), self::config()->get('login_url'));
+        return Controller::join_links(Director::baseURL(), Security::config()->get('login_url'));
     }
 
 
@@ -1195,7 +1195,7 @@ public static function login_url()
      */
     public static function logout_url()
     {
-        $logoutUrl = Controller::join_links(Director::baseURL(), self::config()->get('logout_url'));
+        $logoutUrl = Controller::join_links(Director::baseURL(), Security::config()->get('logout_url'));
         return SecurityToken::inst()->addToUrl($logoutUrl);
     }
 
@@ -1208,7 +1208,7 @@ public static function logout_url()
      */
     public static function lost_password_url()
     {
-        return Controller::join_links(Director::baseURL(), self::config()->get('lost_password_url'));
+        return Controller::join_links(Director::baseURL(), Security::config()->get('lost_password_url'));
     }
 
     /**
diff --git a/src/Security/SecurityToken.php b/src/Security/SecurityToken.php
index e6ba9c2f0e9..7c7ce6b9014 100644
--- a/src/Security/SecurityToken.php
+++ b/src/Security/SecurityToken.php
@@ -66,7 +66,7 @@ class SecurityToken implements TemplateGlobalProvider
      */
     public function __construct($name = null)
     {
-        $this->name = $name ?: self::get_default_name();
+        $this->name = $name ?: SecurityToken::get_default_name();
     }
 
     /**
@@ -76,11 +76,11 @@ public function __construct($name = null)
      */
     public static function inst()
     {
-        if (!self::$inst) {
-            self::$inst = new SecurityToken();
+        if (!SecurityToken::$inst) {
+            SecurityToken::$inst = new SecurityToken();
         }
 
-        return self::$inst;
+        return SecurityToken::$inst;
     }
 
     /**
@@ -89,8 +89,8 @@ public static function inst()
      */
     public static function disable()
     {
-        self::$enabled = false;
-        self::$inst = new NullSecurityToken();
+        SecurityToken::$enabled = false;
+        SecurityToken::$inst = new NullSecurityToken();
     }
 
     /**
@@ -98,8 +98,8 @@ public static function disable()
      */
     public static function enable()
     {
-        self::$enabled = true;
-        self::$inst = new SecurityToken();
+        SecurityToken::$enabled = true;
+        SecurityToken::$inst = new SecurityToken();
     }
 
     /**
@@ -107,7 +107,7 @@ public static function enable()
      */
     public static function is_enabled()
     {
-        return self::$enabled;
+        return SecurityToken::$enabled;
     }
 
     /**
@@ -115,7 +115,7 @@ public static function is_enabled()
      */
     public static function get_default_name()
     {
-        return self::$default_name;
+        return SecurityToken::$default_name;
     }
 
     /**
diff --git a/src/Security/SudoMode/SudoModeService.php b/src/Security/SudoMode/SudoModeService.php
index 33deb10bf88..74fa8547fe4 100644
--- a/src/Security/SudoMode/SudoModeService.php
+++ b/src/Security/SudoMode/SudoModeService.php
@@ -27,7 +27,7 @@ class SudoModeService implements SudoModeServiceInterface
 
     public function check(Session $session): bool
     {
-        $lastActivated = $session->get(self::SUDO_MODE_SESSION_KEY);
+        $lastActivated = $session->get(SudoModeService::SUDO_MODE_SESSION_KEY);
         // Not activated at all
         if (!$lastActivated) {
             return false;
@@ -41,7 +41,7 @@ public function check(Session $session): bool
 
     public function activate(Session $session): bool
     {
-        $session->set(self::SUDO_MODE_SESSION_KEY, DBDatetime::now()->getTimestamp());
+        $session->set(SudoModeService::SUDO_MODE_SESSION_KEY, DBDatetime::now()->getTimestamp());
         return true;
     }
 
diff --git a/src/View/Embed/EmbedContainer.php b/src/View/Embed/EmbedContainer.php
index 5ede0200f40..b7836cb4ab7 100644
--- a/src/View/Embed/EmbedContainer.php
+++ b/src/View/Embed/EmbedContainer.php
@@ -119,7 +119,7 @@ public function getOptions(): array
         return $this->options;
     }
 
-    public function setOptions(array $options): self
+    public function setOptions(array $options): EmbedContainer
     {
         $this->options = $options;
         return $this;
diff --git a/src/View/Parsers/HtmlDiff.php b/src/View/Parsers/HtmlDiff.php
index 2ee11e6b126..17ea1763911 100644
--- a/src/View/Parsers/HtmlDiff.php
+++ b/src/View/Parsers/HtmlDiff.php
@@ -31,21 +31,21 @@ public static function compareHtml(string|array $from, string|array $to, bool $e
     {
         // Get HTML chunks even if we're going to escape it later
         // The diff algorithm sees "<span>some" as a single piece rather than "<span>" and "some" being separate
-        $from = self::explodeToHtmlChunks($from);
-        $to = self::explodeToHtmlChunks($to);
+        $from = HtmlDiff::explodeToHtmlChunks($from);
+        $to = HtmlDiff::explodeToHtmlChunks($to);
 
         // Diff the chunks
-        $differ = self::getDiffer();
+        $differ = HtmlDiff::getDiffer();
         $diff = $differ->diffToArray($from, $to);
 
         // If we aren't escaping the HTML, convert the first diff into clean HTML blocks and then run a new diff
         // on the blocks to get an end result that doesn't have broken HTML
         if (!$escape) {
-            $diifAsBlocks = self::convertDiffToHtmlBlocks($diff);
-            $diff = $differ->diffToArray($diifAsBlocks[self::OLD_VAL], $diifAsBlocks[self::NEW_VAL]);
+            $diifAsBlocks = HtmlDiff::convertDiffToHtmlBlocks($diff);
+            $diff = $differ->diffToArray($diifAsBlocks[HtmlDiff::OLD_VAL], $diifAsBlocks[HtmlDiff::NEW_VAL]);
         }
 
-        $diff = self::createFinalDiffBlocks($diff, $escape);
+        $diff = HtmlDiff::createFinalDiffBlocks($diff, $escape);
 
         // Take the diff and slap the appropriate <ins> and <del> tags in place
         $content = '';
@@ -76,7 +76,7 @@ public static function compareHtml(string|array $from, string|array $to, bool $e
             }
         }
 
-        return self::cleanHTML($content);
+        return HtmlDiff::cleanHTML($content);
     }
 
     /**
@@ -94,7 +94,7 @@ private static function createFinalDiffBlocks(array $diff, bool $escaped): array
         foreach ($diff as $edit) {
             list($value, $type) = $edit;
             $isClosingTag = !$escaped && str_starts_with($value, '</');
-            $isOpeningNonVoidTag = !$escaped && self::isOpeningNonVoidTag($value);
+            $isOpeningNonVoidTag = !$escaped && HtmlDiff::isOpeningNonVoidTag($value);
 
             // If we were building a DIFFERENT type of block, or we've run out of open tags and are closing something
             // earlier in the chain, close the previous block and start a new one
@@ -139,8 +139,8 @@ private static function createFinalDiffBlocks(array $diff, bool $escaped): array
      */
     private static function convertDiffToHtmlBlocks(array $diff): array
     {
-        $openTagsInBlock[self::OLD_VAL] = $openTagsInBlock[self::NEW_VAL] = 0;
-        $htmlBlocks[self::OLD_VAL] = $htmlBlocks[self::NEW_VAL] = [];
+        $openTagsInBlock[HtmlDiff::OLD_VAL] = $openTagsInBlock[HtmlDiff::NEW_VAL] = 0;
+        $htmlBlocks[HtmlDiff::OLD_VAL] = $htmlBlocks[HtmlDiff::NEW_VAL] = [];
 
         foreach ($diff as $edit) {
             list($value, $type) = $edit;
@@ -149,16 +149,16 @@ private static function convertDiffToHtmlBlocks(array $diff): array
                     if ($value === '') {
                         break;
                     }
-                    self::addToHtmlBlocks($htmlBlocks, $openTagsInBlock, self::OLD_VAL, false, $value);
-                    self::addToHtmlBlocks($htmlBlocks, $openTagsInBlock, self::NEW_VAL, false, $value);
+                    HtmlDiff::addToHtmlBlocks($htmlBlocks, $openTagsInBlock, HtmlDiff::OLD_VAL, false, $value);
+                    HtmlDiff::addToHtmlBlocks($htmlBlocks, $openTagsInBlock, HtmlDiff::NEW_VAL, false, $value);
                     break;
 
                 case Differ::ADDED:
-                    self::addToHtmlBlocks($htmlBlocks, $openTagsInBlock, self::NEW_VAL, true, $value);
+                    HtmlDiff::addToHtmlBlocks($htmlBlocks, $openTagsInBlock, HtmlDiff::NEW_VAL, true, $value);
                     break;
 
                 case Differ::REMOVED:
-                    self::addToHtmlBlocks($htmlBlocks, $openTagsInBlock, self::OLD_VAL, true, $value);
+                    HtmlDiff::addToHtmlBlocks($htmlBlocks, $openTagsInBlock, HtmlDiff::OLD_VAL, true, $value);
                     break;
             }
         }
@@ -186,7 +186,7 @@ private static function addToHtmlBlocks(
             $htmlBlocks[$oldOrNew][] = $value;
         }
 
-        if ($canAddTagsToBlock && self::isOpeningNonVoidTag($value)) {
+        if ($canAddTagsToBlock && HtmlDiff::isOpeningNonVoidTag($value)) {
             // If we're mid block or explicitly looking for new tags, we should add any new non-void tags to the block
             $openTagsInBlock[$oldOrNew]++;
         } elseif ($alreadyMidBlock && str_starts_with($value, '</')) {
@@ -254,13 +254,13 @@ private static function explodeToHtmlChunks(string|array $content): array
      *  This cleans code if possible, using an instance of HTMLCleaner
      *
      * @param ?HTMLCleaner $cleaner Optional instance of a HTMLCleaner class to
-     *    use, overriding self::$html_cleaner_class
+     *    use, overriding HtmlDiff::$html_cleaner_class
      */
     private static function cleanHTML(string $content, ?HTMLCleaner $cleaner = null): string
     {
         if (!$cleaner) {
-            if (self::$html_cleaner_class && class_exists(self::$html_cleaner_class)) {
-                $cleaner = Injector::inst()->create(self::$html_cleaner_class);
+            if (HtmlDiff::$html_cleaner_class && class_exists(HtmlDiff::$html_cleaner_class)) {
+                $cleaner = Injector::inst()->create(HtmlDiff::$html_cleaner_class);
             } else {
                 //load cleaner if the dependent class is available
                 $cleaner = HTMLCleaner::inst();
@@ -284,9 +284,9 @@ private static function cleanHTML(string $content, ?HTMLCleaner $cleaner = null)
 
     private static function getDiffer(): Differ
     {
-        if (!self::$differ) {
-            self::$differ = new Differ();
+        if (!HtmlDiff::$differ) {
+            HtmlDiff::$differ = new Differ();
         }
-        return self::$differ;
+        return HtmlDiff::$differ;
     }
 }
diff --git a/src/View/Parsers/SQLFormatter.php b/src/View/Parsers/SQLFormatter.php
index fefc024a4e0..4a73556a2c5 100644
--- a/src/View/Parsers/SQLFormatter.php
+++ b/src/View/Parsers/SQLFormatter.php
@@ -58,7 +58,7 @@ public function formatHTML($sql)
     protected function addNewlines($sql, $useHtmlFormatting = false)
     {
         $eol = PHP_EOL;
-        foreach (self::$newline_before_tokens as $token) {
+        foreach (SQLFormatter::$newline_before_tokens as $token) {
             $breakToken = ($useHtmlFormatting) ? "<br />$eol" : $eol;
             $sql = preg_replace('/[^\n](' . $token . ')/', $breakToken . '$1', $sql ?? '');
         }
diff --git a/src/View/Parsers/ShortcodeParser.php b/src/View/Parsers/ShortcodeParser.php
index 1032c862af0..2031a1645f8 100644
--- a/src/View/Parsers/ShortcodeParser.php
+++ b/src/View/Parsers/ShortcodeParser.php
@@ -58,11 +58,11 @@ public function img_shortcode($attrs)
      */
     public static function get($identifier = 'default')
     {
-        if (!array_key_exists($identifier, self::$instances)) {
-            self::$instances[$identifier] = static::create();
+        if (!array_key_exists($identifier, ShortcodeParser::$instances)) {
+            ShortcodeParser::$instances[$identifier] = static::create();
         }
 
-        return self::$instances[$identifier];
+        return ShortcodeParser::$instances[$identifier];
     }
 
     /**
@@ -72,7 +72,7 @@ public static function get($identifier = 'default')
      */
     public static function get_active()
     {
-        return static::get(self::$active_instance);
+        return static::get(ShortcodeParser::$active_instance);
     }
 
     /**
@@ -82,7 +82,7 @@ public static function get_active()
      */
     public static function set_active($identifier)
     {
-        self::$active_instance = (string) $identifier;
+        ShortcodeParser::$active_instance = (string) $identifier;
     }
 
     // --------------------------------------------------------------------------------------------------------------
@@ -192,7 +192,7 @@ public function getShortcodeReplacementText($tag, $extra = [], $isHTMLAllowed =
         if ($content === false) {
             if (ShortcodeParser::$error_behavior == ShortcodeParser::ERROR) {
                 throw new \InvalidArgumentException('Unknown shortcode tag ' . $tag['open']);
-            } elseif (self::$error_behavior == self::WARN && $isHTMLAllowed) {
+            } elseif (ShortcodeParser::$error_behavior == ShortcodeParser::WARN && $isHTMLAllowed) {
                 $content = '<strong class="warning">' . $tag['text'] . '</strong>';
             } elseif (ShortcodeParser::$error_behavior == ShortcodeParser::STRIP) {
                 return '';
@@ -271,7 +271,7 @@ protected function insertListAfter($new, $after)
 
     protected static function attrrx()
     {
-        return '/' . self::$attrrx . '/xS';
+        return '/' . ShortcodeParser::$attrrx . '/xS';
     }
 
     protected static $tagrx = '
@@ -296,7 +296,7 @@ protected static function attrrx()
 
     protected static function tagrx()
     {
-        return '/' . sprintf(self::$tagrx, self::$attrrx) . '/xS';
+        return '/' . sprintf(ShortcodeParser::$tagrx, ShortcodeParser::$attrrx) . '/xS';
     }
 
     const WARN = 'warn';
@@ -304,7 +304,7 @@ protected static function tagrx()
     const LEAVE = 'leave';
     const ERROR = 'error';
 
-    public static $error_behavior = self::LEAVE;
+    public static $error_behavior = ShortcodeParser::LEAVE;
 
 
     /**
@@ -380,7 +380,7 @@ public function extractTags($content)
                 }
 
                 if ($err) {
-                    if (self::$error_behavior == self::ERROR) {
+                    if (ShortcodeParser::$error_behavior == ShortcodeParser::ERROR) {
                         throw new \Exception($err);
                     }
                 } else {
@@ -407,9 +407,9 @@ public function extractTags($content)
         }
 
         // Step 3: remove any tags that don't have handlers registered
-        // Only do this if self::$error_behavior == self::LEAVE
+        // Only do this if ShortcodeParser::$error_behavior == ShortcodeParser::LEAVE
         // This is optional but speeds things up.
-        if (self::$error_behavior == self::LEAVE) {
+        if (ShortcodeParser::$error_behavior == ShortcodeParser::LEAVE) {
             foreach ($tags as $i => $tag) {
                 if (empty($this->shortcodes[$tag['open']])) {
                     unset($tags[$i]);
@@ -497,7 +497,7 @@ protected function replaceElementTagsWithMarkers($content)
         $tags = $this->extractTags($content);
 
         if ($tags) {
-            $markerClass = self::$marker_class;
+            $markerClass = ShortcodeParser::$marker_class;
 
             $content = $this->replaceTagsWithText($content, $tags, function ($idx, $tag) use ($markerClass) {
                 return '<img class="' . $markerClass . '" data-tagid="' . $idx . '" />';
@@ -522,7 +522,7 @@ protected function findParentsForMarkers($nodes)
             do {
                 $parent = $parent->parentNode;
             } while ($parent instanceof DOMElement &&
-                !in_array(strtolower($parent->tagName ?? ''), self::$block_level_elements)
+                !in_array(strtolower($parent->tagName ?? ''), ShortcodeParser::$block_level_elements)
             );
 
             $node->setAttribute('data-parentid', count($parents ?? []));
@@ -566,14 +566,14 @@ protected function findParentsForMarkers($nodes)
     protected function moveMarkerToCompliantHome($node, $parent, $location)
     {
         // Move before block parent
-        if ($location == self::BEFORE) {
+        if ($location == ShortcodeParser::BEFORE) {
             if (isset($parent->parentNode)) {
                 $parent->parentNode->insertBefore($node, $parent);
             }
-        } elseif ($location == self::AFTER) {
+        } elseif ($location == ShortcodeParser::AFTER) {
             // Move after block parent
             $this->insertAfter($node, $parent);
-        } elseif ($location == self::SPLIT) {
+        } elseif ($location == ShortcodeParser::SPLIT) {
             // Split parent at node
             $at = $node;
             $splitee = $node->parentNode;
@@ -593,9 +593,9 @@ protected function moveMarkerToCompliantHome($node, $parent, $location)
             }
 
             $this->insertAfter($node, $parent);
-        } elseif ($location == self::INLINE) {
+        } elseif ($location == ShortcodeParser::INLINE) {
             // Do nothing
-            if (in_array(strtolower($node->tagName ?? ''), self::$block_level_elements)) {
+            if (in_array(strtolower($node->tagName ?? ''), ShortcodeParser::$block_level_elements)) {
                 user_error(
                     'Requested to insert block tag ' . $node->tagName . ' inline - probably this will break HTML compliance',
                     E_USER_WARNING
@@ -661,7 +661,7 @@ public function parse($content)
 
             // Now parse the result into a DOM
             if (!$htmlvalue->isValid()) {
-                if (self::$error_behavior == self::ERROR) {
+                if (ShortcodeParser::$error_behavior == ShortcodeParser::ERROR) {
                     throw new \Exception('Couldn\'t decode HTML when processing short codes');
                 } else {
                     $continue = false;
@@ -674,7 +674,7 @@ public function parse($content)
             $this->replaceAttributeTagsWithContent($htmlvalue);
 
             // Find all the element scoped shortcode markers
-            $shortcodes = $htmlvalue->query('//img[@class="' . self::$marker_class . '"]');
+            $shortcodes = $htmlvalue->query('//img[@class="' . ShortcodeParser::$marker_class . '"]');
 
             // Find the parents. Do this before DOM modification, since SPLIT might cause parents to move otherwise
             $parents = $this->findParentsForMarkers($shortcodes);
@@ -691,19 +691,19 @@ public function parse($content)
                     $class = $tag['attrs']['class'];
                 }
 
-                $location = self::INLINE;
+                $location = ShortcodeParser::INLINE;
                 if ($class == 'left' || $class == 'right') {
-                    $location = self::BEFORE;
+                    $location = ShortcodeParser::BEFORE;
                 }
                 /**
                  * Below code disabled due to https://github.com/silverstripe/silverstripe-framework/issues/5987
                 if ($class == 'center' || $class == 'leftAlone') {
-                    $location = self::SPLIT;
+                    $location = ShortcodeParser::SPLIT;
                 }
                  */
 
                 if (!$parent) {
-                    if ($location !== self::INLINE) {
+                    if ($location !== ShortcodeParser::INLINE) {
                         throw new \RuntimeException(
                             "Parent block for shortcode couldn't be found, but location wasn't INLINE"
                         );
@@ -722,7 +722,7 @@ public function parse($content)
             $content = preg_replace_callback(
                 // Not a general-case parser; assumes that the HTML generated in replaceElementTagsWithMarkers()
                 // hasn't been heavily modified
-                '/<img[^>]+class="' . preg_quote(self::$marker_class) . '"[^>]+data-tagid="([^"]+)"[^>]*>/i',
+                '/<img[^>]+class="' . preg_quote(ShortcodeParser::$marker_class) . '"[^>]+data-tagid="([^"]+)"[^>]*>/i',
                 function ($matches) use ($tags, $parser) {
                     $tag = $tags[$matches[1]];
                     return $parser->getShortcodeReplacementText($tag);
diff --git a/src/View/Requirements.php b/src/View/Requirements.php
index c757f2ba2d9..0656d26dd43 100644
--- a/src/View/Requirements.php
+++ b/src/View/Requirements.php
@@ -31,7 +31,7 @@ public static function flush()
     {
         $disabled = Config::inst()->get(static::class, 'disable_flush_combined');
         if (!$disabled) {
-            self::delete_all_combined_files();
+            Requirements::delete_all_combined_files();
         }
     }
 
@@ -42,7 +42,7 @@ public static function flush()
      */
     public static function set_combined_files_enabled($enable)
     {
-        self::backend()->setCombinedFilesEnabled($enable);
+        Requirements::backend()->setCombinedFilesEnabled($enable);
     }
 
     /**
@@ -52,7 +52,7 @@ public static function set_combined_files_enabled($enable)
      */
     public static function get_combined_files_enabled()
     {
-        return self::backend()->getCombinedFilesEnabled();
+        return Requirements::backend()->getCombinedFilesEnabled();
     }
 
     /**
@@ -62,7 +62,7 @@ public static function get_combined_files_enabled()
      */
     public static function set_combined_files_folder($folder)
     {
-        self::backend()->setCombinedFilesFolder($folder);
+        Requirements::backend()->setCombinedFilesFolder($folder);
     }
 
     /**
@@ -75,7 +75,7 @@ public static function set_combined_files_folder($folder)
      */
     public static function set_suffix_requirements($var)
     {
-        self::backend()->setSuffixRequirements($var);
+        Requirements::backend()->setSuffixRequirements($var);
     }
 
     /**
@@ -85,7 +85,7 @@ public static function set_suffix_requirements($var)
      */
     public static function get_suffix_requirements()
     {
-        return self::backend()->getSuffixRequirements();
+        return Requirements::backend()->getSuffixRequirements();
     }
 
     /**
@@ -101,10 +101,10 @@ public static function get_suffix_requirements()
      */
     public static function backend()
     {
-        if (!self::$backend) {
-            self::$backend = Requirements_Backend::create();
+        if (!Requirements::$backend) {
+            Requirements::$backend = Requirements_Backend::create();
         }
-        return self::$backend;
+        return Requirements::$backend;
     }
 
     /**
@@ -114,7 +114,7 @@ public static function backend()
      */
     public static function set_backend(Requirements_Backend $backend)
     {
-        self::$backend = $backend;
+        Requirements::$backend = $backend;
     }
 
     /**
@@ -128,7 +128,7 @@ public static function set_backend(Requirements_Backend $backend)
      */
     public static function javascript($file, $options = [])
     {
-        self::backend()->javascript($file, $options);
+        Requirements::backend()->javascript($file, $options);
     }
 
     /**
@@ -139,7 +139,7 @@ public static function javascript($file, $options = [])
      */
     public static function customScript($script, $uniquenessID = null)
     {
-        self::backend()->customScript($script, $uniquenessID);
+        Requirements::backend()->customScript($script, $uniquenessID);
     }
 
     /**
@@ -154,7 +154,7 @@ public static function customScript($script, $uniquenessID = null)
      */
     public static function customScriptWithAttributes(string $script, array $options = [], string|int|null $uniquenessID = null)
     {
-        self::backend()->customScriptWithAttributes($script, $options, $uniquenessID);
+        Requirements::backend()->customScriptWithAttributes($script, $options, $uniquenessID);
     }
 
     /**
@@ -164,7 +164,7 @@ public static function customScriptWithAttributes(string $script, array $options
      */
     public static function get_custom_scripts()
     {
-        return self::backend()->getCustomScripts();
+        return Requirements::backend()->getCustomScripts();
     }
 
     /**
@@ -175,7 +175,7 @@ public static function get_custom_scripts()
      */
     public static function customCSS($script, $uniquenessID = null)
     {
-        self::backend()->customCSS($script, $uniquenessID);
+        Requirements::backend()->customCSS($script, $uniquenessID);
     }
 
     /**
@@ -186,7 +186,7 @@ public static function customCSS($script, $uniquenessID = null)
      */
     public static function insertHeadTags($html, $uniquenessID = null)
     {
-        self::backend()->insertHeadTags($html, $uniquenessID);
+        Requirements::backend()->insertHeadTags($html, $uniquenessID);
     }
 
     /**
@@ -199,7 +199,7 @@ public static function insertHeadTags($html, $uniquenessID = null)
      */
     public static function javascriptTemplate($file, $vars, $uniquenessID = null)
     {
-        self::backend()->javascriptTemplate($file, $vars, $uniquenessID);
+        Requirements::backend()->javascriptTemplate($file, $vars, $uniquenessID);
     }
 
     /**
@@ -214,7 +214,7 @@ public static function javascriptTemplate($file, $vars, $uniquenessID = null)
      */
     public static function css($file, $media = null, $options = [])
     {
-        self::backend()->css($file, $media, $options);
+        Requirements::backend()->css($file, $media, $options);
     }
 
     /**
@@ -230,7 +230,7 @@ public static function css($file, $media = null, $options = [])
      */
     public static function themedCSS($name, $media = null)
     {
-        self::backend()->themedCSS($name, $media);
+        Requirements::backend()->themedCSS($name, $media);
     }
 
     /**
@@ -246,7 +246,7 @@ public static function themedCSS($name, $media = null)
      */
     public static function themedJavascript($name, $type = null)
     {
-        self::backend()->themedJavascript($name, $type);
+        Requirements::backend()->themedJavascript($name, $type);
     }
 
     /**
@@ -259,7 +259,7 @@ public static function themedJavascript($name, $type = null)
      */
     public static function clear($fileOrID = null)
     {
-        self::backend()->clear($fileOrID);
+        Requirements::backend()->clear($fileOrID);
     }
 
     /**
@@ -267,7 +267,7 @@ public static function clear($fileOrID = null)
      */
     public static function restore()
     {
-        self::backend()->restore();
+        Requirements::backend()->restore();
     }
 
     /**
@@ -285,7 +285,7 @@ public static function restore()
      */
     public static function block($fileOrID)
     {
-        self::backend()->block($fileOrID);
+        Requirements::backend()->block($fileOrID);
     }
 
     /**
@@ -295,7 +295,7 @@ public static function block($fileOrID)
      */
     public static function unblock($fileOrID)
     {
-        self::backend()->unblock($fileOrID);
+        Requirements::backend()->unblock($fileOrID);
     }
 
     /**
@@ -303,7 +303,7 @@ public static function unblock($fileOrID)
      */
     public static function unblock_all()
     {
-        self::backend()->unblockAll();
+        Requirements::backend()->unblockAll();
     }
 
     /**
@@ -317,7 +317,7 @@ public static function unblock_all()
      */
     public static function includeInHTML($content)
     {
-        return self::backend()->includeInHTML($content);
+        return Requirements::backend()->includeInHTML($content);
     }
 
     /**
@@ -328,7 +328,7 @@ public static function includeInHTML($content)
      */
     public static function include_in_response(HTTPResponse $response)
     {
-        self::backend()->includeInResponse($response);
+        Requirements::backend()->includeInResponse($response);
     }
 
     /**
@@ -345,7 +345,7 @@ public static function include_in_response(HTTPResponse $response)
      */
     public static function add_i18n_javascript($langDir, $return = false)
     {
-        return self::backend()->add_i18n_javascript($langDir, $return);
+        return Requirements::backend()->add_i18n_javascript($langDir, $return);
     }
 
     /**
@@ -399,7 +399,7 @@ public static function combine_files($combinedFileName, $files, $options = [])
         if (is_string($options)) {
             throw new InvalidArgumentException("Invalid $options");
         }
-        self::backend()->combineFiles($combinedFileName, $files, $options);
+        Requirements::backend()->combineFiles($combinedFileName, $files, $options);
     }
 
     /**
@@ -411,7 +411,7 @@ public static function combine_files($combinedFileName, $files, $options = [])
      */
     public static function get_combine_files()
     {
-        return self::backend()->getCombinedFiles();
+        return Requirements::backend()->getCombinedFiles();
     }
 
     /**
@@ -420,7 +420,7 @@ public static function get_combine_files()
      */
     public static function delete_all_combined_files()
     {
-        self::backend()->deleteAllCombinedFiles();
+        Requirements::backend()->deleteAllCombinedFiles();
     }
 
     /**
@@ -428,7 +428,7 @@ public static function delete_all_combined_files()
      */
     public static function clear_combined_files()
     {
-        self::backend()->clearCombinedFiles();
+        Requirements::backend()->clearCombinedFiles();
     }
 
     /**
@@ -436,7 +436,7 @@ public static function clear_combined_files()
      */
     public static function process_combined_files()
     {
-        self::backend()->processCombinedFiles();
+        Requirements::backend()->processCombinedFiles();
     }
 
     /**
@@ -447,7 +447,7 @@ public static function process_combined_files()
      */
     public static function get_write_js_to_body()
     {
-        return self::backend()->getWriteJavascriptToBody();
+        return Requirements::backend()->getWriteJavascriptToBody();
     }
 
     /**
@@ -458,7 +458,7 @@ public static function get_write_js_to_body()
      */
     public static function set_write_js_to_body($var)
     {
-        self::backend()->setWriteJavascriptToBody($var);
+        Requirements::backend()->setWriteJavascriptToBody($var);
     }
 
     /**
@@ -469,7 +469,7 @@ public static function set_write_js_to_body($var)
      */
     public static function get_force_js_to_bottom()
     {
-        return self::backend()->getForceJSToBottom();
+        return Requirements::backend()->getForceJSToBottom();
     }
 
     /**
@@ -480,7 +480,7 @@ public static function get_force_js_to_bottom()
      */
     public static function set_force_js_to_bottom($var)
     {
-        self::backend()->setForceJSToBottom($var);
+        Requirements::backend()->setForceJSToBottom($var);
     }
 
     /**
@@ -490,7 +490,7 @@ public static function set_force_js_to_bottom($var)
      */
     public static function get_minify_combined_js_files()
     {
-        return self::backend()->getMinifyCombinedJSFiles();
+        return Requirements::backend()->getMinifyCombinedJSFiles();
     }
 
     /**
@@ -500,7 +500,7 @@ public static function get_minify_combined_js_files()
      */
     public static function set_minify_combined_js_files($minify)
     {
-        self::backend()->setMinifyCombinedJSFiles($minify);
+        Requirements::backend()->setMinifyCombinedJSFiles($minify);
     }
 
     /**
@@ -510,7 +510,7 @@ public static function set_minify_combined_js_files($minify)
      */
     public static function get_write_header_comments()
     {
-        return self::backend()->getWriteHeaderComment();
+        return Requirements::backend()->getWriteHeaderComment();
     }
 
     /**
@@ -520,7 +520,7 @@ public static function get_write_header_comments()
      */
     public function set_write_header_comments($write)
     {
-        self::backend()->setWriteHeaderComment($write);
+        Requirements::backend()->setWriteHeaderComment($write);
     }
 
 
@@ -529,6 +529,6 @@ public function set_write_header_comments($write)
      */
     public static function debug()
     {
-        self::backend()->debug();
+        Requirements::backend()->debug();
     }
 }
diff --git a/src/View/SSViewer.php b/src/View/SSViewer.php
index c74766515d3..3b82eb3fdd9 100644
--- a/src/View/SSViewer.php
+++ b/src/View/SSViewer.php
@@ -194,7 +194,7 @@ public function __construct($templates, TemplateParser $parser = null)
             $message = 'None of the following templates could be found: ';
             $message .= print_r($templates, true);
 
-            $themes = self::get_themes();
+            $themes = SSViewer::get_themes();
             if (!$themes) {
                 $message .= ' (no theme in use)';
             } else {
@@ -210,8 +210,8 @@ public function __construct($templates, TemplateParser $parser = null)
      */
     public static function flush()
     {
-        self::flush_template_cache(true);
-        self::flush_cacheblock_cache(true);
+        SSViewer::flush_template_cache(true);
+        SSViewer::flush_cacheblock_cache(true);
     }
 
     /**
@@ -261,7 +261,7 @@ public static function add_themes($themes = [])
      */
     public static function get_themes()
     {
-        $default = [self::PUBLIC_THEME, self::DEFAULT_THEME];
+        $default = [SSViewer::PUBLIC_THEME, SSViewer::DEFAULT_THEME];
 
         if (!SSViewer::config()->uninherited('theme_enabled')) {
             return $default;
@@ -401,7 +401,7 @@ public function setTemplate($templates)
      */
     public static function chooseTemplate($templates)
     {
-        return ThemeResourceLoader::inst()->findTemplate($templates, self::get_themes());
+        return ThemeResourceLoader::inst()->findTemplate($templates, SSViewer::get_themes());
     }
 
     /**
@@ -436,7 +436,7 @@ public function getParser()
      */
     public static function hasTemplate($templates)
     {
-        return (bool)ThemeResourceLoader::inst()->findTemplate($templates, self::get_themes());
+        return (bool)ThemeResourceLoader::inst()->findTemplate($templates, SSViewer::get_themes());
     }
 
     /**
@@ -465,7 +465,7 @@ public function exists()
      */
     public static function getTemplateFileByType($identifier, $type = null)
     {
-        return ThemeResourceLoader::inst()->findTemplate(['type' => $type, $identifier], self::get_themes());
+        return ThemeResourceLoader::inst()->findTemplate(['type' => $type, $identifier], SSViewer::get_themes());
     }
 
     /**
@@ -478,14 +478,14 @@ public static function getTemplateFileByType($identifier, $type = null)
      */
     public static function flush_template_cache($force = false)
     {
-        if (!self::$template_cache_flushed || $force) {
+        if (!SSViewer::$template_cache_flushed || $force) {
             $dir = dir(TEMP_PATH);
             while (false !== ($file = $dir->read())) {
                 if (strstr($file ?? '', '.cache')) {
                     unlink(TEMP_PATH . DIRECTORY_SEPARATOR . $file);
                 }
             }
-            self::$template_cache_flushed = true;
+            SSViewer::$template_cache_flushed = true;
         }
     }
 
@@ -499,12 +499,12 @@ public static function flush_template_cache($force = false)
      */
     public static function flush_cacheblock_cache($force = false)
     {
-        if (!self::$cacheblock_cache_flushed || $force) {
+        if (!SSViewer::$cacheblock_cache_flushed || $force) {
             $cache = Injector::inst()->get(CacheInterface::class . '.cacheblock');
             $cache->clear();
 
 
-            self::$cacheblock_cache_flushed = true;
+            SSViewer::$cacheblock_cache_flushed = true;
         }
     }
 
diff --git a/src/View/SSViewer_DataPresenter.php b/src/View/SSViewer_DataPresenter.php
index 9a65d01fae7..a72f5051b27 100644
--- a/src/View/SSViewer_DataPresenter.php
+++ b/src/View/SSViewer_DataPresenter.php
@@ -79,11 +79,11 @@ public function __construct(
      */
     protected function cacheGlobalProperties()
     {
-        if (self::$globalProperties !== null) {
+        if (SSViewer_DataPresenter::$globalProperties !== null) {
             return;
         }
 
-        self::$globalProperties = $this->getPropertiesFromProvider(
+        SSViewer_DataPresenter::$globalProperties = $this->getPropertiesFromProvider(
             TemplateGlobalProvider::class,
             'get_template_global_variables'
         );
@@ -94,11 +94,11 @@ protected function cacheGlobalProperties()
      */
     protected function cacheIteratorProperties()
     {
-        if (self::$iteratorProperties !== null) {
+        if (SSViewer_DataPresenter::$iteratorProperties !== null) {
             return;
         }
 
-        self::$iteratorProperties = $this->getPropertiesFromProvider(
+        SSViewer_DataPresenter::$iteratorProperties = $this->getPropertiesFromProvider(
             TemplateIteratorProvider::class,
             'get_template_iterator_variables',
             true // Call non-statically
@@ -388,8 +388,8 @@ protected function getValueSource($property)
         }
 
         // Then for iterator-specific overrides
-        if (array_key_exists($property, self::$iteratorProperties)) {
-            $source = self::$iteratorProperties[$property];
+        if (array_key_exists($property, SSViewer_DataPresenter::$iteratorProperties)) {
+            $source = SSViewer_DataPresenter::$iteratorProperties[$property];
             /** @var TemplateIteratorProvider $implementor */
             $implementor = $source['implementor'];
             if ($this->itemIterator) {
@@ -408,9 +408,9 @@ protected function getValueSource($property)
         }
 
         // And finally for global overrides
-        if (array_key_exists($property, self::$globalProperties)) {
+        if (array_key_exists($property, SSViewer_DataPresenter::$globalProperties)) {
             return [
-                'source' => self::$globalProperties[$property] // get the method call
+                'source' => SSViewer_DataPresenter::$globalProperties[$property] // get the method call
             ];
         }
 
diff --git a/src/View/SSViewer_Scope.php b/src/View/SSViewer_Scope.php
index aa4ee206557..f82b84062d8 100644
--- a/src/View/SSViewer_Scope.php
+++ b/src/View/SSViewer_Scope.php
@@ -127,7 +127,7 @@ public function getItem()
     /**
      * Called at the start of every lookup chain by SSTemplateParser to indicate a new lookup from local scope
      *
-     * @return self
+     * @return SSViewer_Scope
      */
     public function locally()
     {
@@ -249,7 +249,7 @@ public function self()
     /**
      * Jump to the last item in the stack, called when a new item is added before a loop/with
      *
-     * @return self
+     * @return SSViewer_Scope
      */
     public function pushScope()
     {
@@ -271,7 +271,7 @@ public function pushScope()
     /**
      * Jump back to "previous" item in the stack, called after a loop/with block
      *
-     * @return self
+     * @return SSViewer_Scope
      */
     public function popScope()
     {
diff --git a/src/View/Shortcodes/EmbedShortcodeProvider.php b/src/View/Shortcodes/EmbedShortcodeProvider.php
index 9a8c524506f..89806d6bc26 100644
--- a/src/View/Shortcodes/EmbedShortcodeProvider.php
+++ b/src/View/Shortcodes/EmbedShortcodeProvider.php
@@ -200,7 +200,7 @@ protected static function videoEmbed($arguments, $content)
             'Content' => DBField::create_field('HTMLFragment', $content)
         ];
 
-        return ArrayData::create($data)->renderWith(self::class . '_video')->forTemplate();
+        return ArrayData::create($data)->renderWith(EmbedShortcodeProvider::class . '_video')->forTemplate();
     }
 
     /**
@@ -220,7 +220,7 @@ protected static function linkEmbed($arguments, $href, $title)
             'Title' => !empty($arguments['caption']) ? ($arguments['caption']) : $title
         ];
 
-        return ArrayData::create($data)->renderWith(self::class . '_link')->forTemplate();
+        return ArrayData::create($data)->renderWith(EmbedShortcodeProvider::class . '_link')->forTemplate();
     }
 
     /**
@@ -238,7 +238,7 @@ protected static function photoEmbed($arguments, $src)
             'Src' => $src
         ];
 
-        return ArrayData::create($data)->renderWith(self::class . '_photo')->forTemplate();
+        return ArrayData::create($data)->renderWith(EmbedShortcodeProvider::class . '_photo')->forTemplate();
     }
 
     /**
@@ -327,10 +327,10 @@ private static function deriveCacheKey(string $url, string $class, string $width
     {
         return implode('-', array_filter([
             'embed-shortcode',
-            self::cleanKeySegment($url),
-            self::cleanKeySegment($class),
-            self::cleanKeySegment($width),
-            self::cleanKeySegment($height)
+            EmbedShortcodeProvider::cleanKeySegment($url),
+            EmbedShortcodeProvider::cleanKeySegment($class),
+            EmbedShortcodeProvider::cleanKeySegment($width),
+            EmbedShortcodeProvider::cleanKeySegment($height)
         ]));
     }
 
diff --git a/src/View/ThemeManifest.php b/src/View/ThemeManifest.php
index f764d71a1b1..402ac4aa6b5 100644
--- a/src/View/ThemeManifest.php
+++ b/src/View/ThemeManifest.php
@@ -161,7 +161,7 @@ public function regenerate($includeTests = false)
      */
     public function handleDirectory($basename, $pathname, $depth)
     {
-        if ($basename !== self::TEMPLATES_DIR) {
+        if ($basename !== ThemeManifest::TEMPLATES_DIR) {
             return;
         }
         $dir = trim(substr(dirname($pathname ?? ''), strlen($this->base ?? '')), '/\\');
diff --git a/src/View/ThemeResourceLoader.php b/src/View/ThemeResourceLoader.php
index 7967c22bdac..8799fe13a66 100644
--- a/src/View/ThemeResourceLoader.php
+++ b/src/View/ThemeResourceLoader.php
@@ -46,7 +46,7 @@ class ThemeResourceLoader implements Flushable, TemplateGlobalProvider
      */
     public static function inst()
     {
-        return self::$instance ? self::$instance : self::$instance = new self();
+        return ThemeResourceLoader::$instance ? ThemeResourceLoader::$instance : ThemeResourceLoader::$instance = new ThemeResourceLoader();
     }
 
     /**
@@ -56,7 +56,7 @@ public static function inst()
      */
     public static function set_instance(ThemeResourceLoader $instance)
     {
-        self::$instance = $instance;
+        ThemeResourceLoader::$instance = $instance;
     }
 
     public function __construct($base = null)
@@ -390,7 +390,7 @@ public function getThemePaths($themes = null)
      */
     public static function flush()
     {
-        self::inst()->getCache()->clear();
+        ThemeResourceLoader::inst()->getCache()->clear();
     }
 
     /**
diff --git a/src/View/ViewableData.php b/src/View/ViewableData.php
index f5f19ec8c0f..d729d36da72 100644
--- a/src/View/ViewableData.php
+++ b/src/View/ViewableData.php
@@ -267,7 +267,7 @@ private function isAccessibleMethod(string $method): bool
             return $this->hasCustomMethod($method);
         }
         // All methods defined on ViewableData are accessible to ViewableData
-        if (static::class === self::class) {
+        if (static::class === ViewableData::class) {
             return true;
         }
         // Private methods defined on subclasses are not accessible to ViewableData
@@ -284,7 +284,7 @@ private function isAccessibleProperty(string $property): bool
         if (!property_exists($this, $property)) {
             return false;
         }
-        if (static::class === self::class) {
+        if (static::class === ViewableData::class) {
             return true;
         }
         $reflectionProperty = new ReflectionProperty($this, $property);
@@ -665,7 +665,7 @@ public function getIterator(): Traversable
      */
     public function getViewerTemplates($suffix = '')
     {
-        return SSViewer::get_templates_by_class(static::class, $suffix, self::class);
+        return SSViewer::get_templates_by_class(static::class, $suffix, ViewableData::class);
     }
 
     /**
@@ -689,7 +689,7 @@ public function Me()
      * @return string
      * @uses ClassInfo
      */
-    public function CSSClasses($stopAtClass = self::class)
+    public function CSSClasses($stopAtClass = ViewableData::class)
     {
         $classes       = [];
         $classAncestry = array_reverse(ClassInfo::ancestry(static::class) ?? []);
diff --git a/src/i18n/TextCollection/i18nTextCollector.php b/src/i18n/TextCollection/i18nTextCollector.php
index fce88716dea..3d3d6fa6f8f 100644
--- a/src/i18n/TextCollection/i18nTextCollector.php
+++ b/src/i18n/TextCollection/i18nTextCollector.php
@@ -474,7 +474,7 @@ private function getModulesAndThemes(): array
             if (!empty($themes)) {
                 foreach ($themes as $theme) {
                     if (is_dir(Path::join(THEMES_PATH, $theme))) {
-                        $modules[self::THEME_PREFIX . $theme] = new Module(Path::join(THEMES_PATH, $theme), BASE_PATH);
+                        $modules[i18nTextCollector::THEME_PREFIX . $theme] = new Module(Path::join(THEMES_PATH, $theme), BASE_PATH);
                     }
                 }
             }
@@ -488,7 +488,7 @@ private function getModulesAndThemes(): array
      */
     private function getModuleName(string $origName, Module $module): string
     {
-        return strpos($origName, self::THEME_PREFIX) === 0 ? $origName : $module->getName();
+        return strpos($origName, i18nTextCollector::THEME_PREFIX) === 0 ? $origName : $module->getName();
     }
 
     /**
@@ -558,7 +558,7 @@ protected function getFileListForModule(Module $module)
         $modulePath = $module->getPath();
 
         // Search all .ss files in themes
-        if (stripos($module->getRelativePath() ?? '', self::THEME_PREFIX) === 0) {
+        if (stripos($module->getRelativePath() ?? '', i18nTextCollector::THEME_PREFIX) === 0) {
             return $this->getFilesRecursive($modulePath, null, 'ss');
         }
 
@@ -608,7 +608,7 @@ public function collectFromCode($content, $fileName, Module $module)
         $inClass = false; // after `class` but before `{`
         $inUse = false; // pulling in classes from other namespaces
         $inArrayClosedBy = false; // Set to the expected closing token, or false if not in array
-        $inSelf = false; // Tracks progress of collecting self::class
+        $inSelf = false; // Tracks progress of collecting i18nTextCollector::class
         $currentEntity = [];
         $currentNameSpace = []; // The actual namespace for the current class
         $currentClass = []; // Class components
@@ -677,7 +677,7 @@ public function collectFromCode($content, $fileName, Module $module)
                     // Skip if previous token was '::'. E.g. 'Object::class'
                     if (is_array($previousToken) && $previousToken[0] === T_DOUBLE_COLON) {
                         if ($inSelf) {
-                            // Handle self::class by allowing logic further down
+                            // Handle i18nTextCollector::class by allowing logic further down
                             // for __CLASS__/__TRAIT__ to handle an array of class parts
                             $id = $id === T_TRAIT ? T_TRAIT_C : T_CLASS_C;
                             $inSelf = false;
@@ -741,7 +741,7 @@ public function collectFromCode($content, $fileName, Module $module)
                     continue;
                 }
 
-                // Start collecting self::class declarations
+                // Start collecting i18nTextCollector::class declarations
                 if ($id === T_STRING && $text === 'self') {
                     $inSelf = true;
                     continue;
@@ -770,7 +770,7 @@ function ($input) {
                         throw new LogicException("Invalid string escape: " . $text);
                     }
                 } elseif ($id === T_CLASS_C || $id === T_TRAIT_C) {
-                    // Evaluate __CLASS__ . '.KEY' and self::class concatenation
+                    // Evaluate __CLASS__ . '.KEY' and i18nTextCollector::class concatenation
                     $text = implode('\\', $currentClass);
                 } else {
                     continue;
diff --git a/src/i18n/i18n.php b/src/i18n/i18n.php
index 5f0b6f3f94e..61ab1ec159b 100644
--- a/src/i18n/i18n.php
+++ b/src/i18n/i18n.php
@@ -264,7 +264,7 @@ public static function encode_plurals($plurals)
     public static function get_closest_translation($locale)
     {
         // Check if exact match
-        $pool = self::getSources()->getKnownLocales();
+        $pool = i18n::getSources()->getKnownLocales();
         if (isset($pool[$locale])) {
             return $locale;
         }
@@ -308,7 +308,7 @@ public static function convert_rfc1766($locale)
     public static function set_locale($locale)
     {
         if ($locale) {
-            self::$current_locale = $locale;
+            i18n::$current_locale = $locale;
         }
     }
 
@@ -321,7 +321,7 @@ public static function set_locale($locale)
      */
     public static function with_locale($locale, $callback)
     {
-        $oldLocale = self::$current_locale;
+        $oldLocale = i18n::$current_locale;
         static::set_locale($locale);
         try {
             return $callback();
@@ -338,10 +338,10 @@ public static function with_locale($locale, $callback)
      */
     public static function get_locale()
     {
-        if (!self::$current_locale) {
-            self::$current_locale = i18n::config()->uninherited('default_locale');
+        if (!i18n::$current_locale) {
+            i18n::$current_locale = i18n::config()->uninherited('default_locale');
         }
-        return self::$current_locale;
+        return i18n::$current_locale;
     }
 
     /**
diff --git a/tests/behat/src/CmsUiContext.php b/tests/behat/src/CmsUiContext.php
index 1adb97252d4..26064890838 100644
--- a/tests/behat/src/CmsUiContext.php
+++ b/tests/behat/src/CmsUiContext.php
@@ -649,7 +649,7 @@ public function theIFillInTheDropdownWith($field, $value)
             $formFields = $this->getSession()->getPage()->findAll(
                 'xpath',
                 sprintf(
-                    '//*[self::select][(./@title="%s")]',
+                    '//*[CmsUiContext::select][(./@title="%s")]',
                     $field
                 )
             );
diff --git a/tests/php/Control/FlushMiddlewareTest/TestFlushable.php b/tests/php/Control/FlushMiddlewareTest/TestFlushable.php
index 7a28aa6ba68..f1c290e1651 100644
--- a/tests/php/Control/FlushMiddlewareTest/TestFlushable.php
+++ b/tests/php/Control/FlushMiddlewareTest/TestFlushable.php
@@ -11,6 +11,6 @@ class TestFlushable implements Flushable, TestOnly
 
     public static function flush()
     {
-        self::$flushed = true;
+        TestFlushable::$flushed = true;
     }
 }
diff --git a/tests/php/Control/RSS/RSSFeedTest.php b/tests/php/Control/RSS/RSSFeedTest.php
index b9150f29d5e..8392dd49599 100644
--- a/tests/php/Control/RSS/RSSFeedTest.php
+++ b/tests/php/Control/RSS/RSSFeedTest.php
@@ -100,8 +100,8 @@ protected function setUp(): void
     {
         parent::setUp();
         Config::modify()->set(Director::class, 'alternate_base_url', '/');
-        if (!self::$original_host) {
-            self::$original_host = $_SERVER['HTTP_HOST'];
+        if (!RSSFeedTest::$original_host) {
+            RSSFeedTest::$original_host = $_SERVER['HTTP_HOST'];
         }
         $_SERVER['HTTP_HOST'] = 'www.example.org';
 
@@ -116,6 +116,6 @@ function () {
     protected function tearDown(): void
     {
         parent::tearDown();
-        $_SERVER['HTTP_HOST'] = self::$original_host;
+        $_SERVER['HTTP_HOST'] = RSSFeedTest::$original_host;
     }
 }
diff --git a/tests/php/Control/RequestHandlingTest/ControllerExtension.php b/tests/php/Control/RequestHandlingTest/ControllerExtension.php
index 44c849a5118..089e43a16a6 100644
--- a/tests/php/Control/RequestHandlingTest/ControllerExtension.php
+++ b/tests/php/Control/RequestHandlingTest/ControllerExtension.php
@@ -27,7 +27,7 @@ public function extendedMethod()
      */
     public function onBeforeHTTPError()
     {
-        self::$called_error = true;
+        ControllerExtension::$called_error = true;
     }
 
     /**
@@ -35,6 +35,6 @@ public function onBeforeHTTPError()
      */
     public function onBeforeHTTPError404()
     {
-        self::$called_404_error = true;
+        ControllerExtension::$called_404_error = true;
     }
 }
diff --git a/tests/php/Dev/DevAdminControllerTest/Controller1.php b/tests/php/Dev/DevAdminControllerTest/Controller1.php
index e2db8f78fc4..e73ee27ccfd 100644
--- a/tests/php/Dev/DevAdminControllerTest/Controller1.php
+++ b/tests/php/Dev/DevAdminControllerTest/Controller1.php
@@ -22,11 +22,11 @@ class Controller1 extends Controller
 
     public function index()
     {
-        echo self::OK_MSG;
+        echo Controller1::OK_MSG;
     }
 
     public function y1Action()
     {
-        echo self::OK_MSG;
+        echo Controller1::OK_MSG;
     }
 }
diff --git a/tests/php/Dev/DevAdminControllerTest/ControllerWithPermissions.php b/tests/php/Dev/DevAdminControllerTest/ControllerWithPermissions.php
index 7cbd2d276ce..3dcda947108 100644
--- a/tests/php/Dev/DevAdminControllerTest/ControllerWithPermissions.php
+++ b/tests/php/Dev/DevAdminControllerTest/ControllerWithPermissions.php
@@ -22,7 +22,7 @@ class ControllerWithPermissions extends Controller implements PermissionProvider
 
     public function index()
     {
-        echo self::OK_MSG;
+        echo ControllerWithPermissions::OK_MSG;
     }
 
     public function canInit()
diff --git a/tests/php/Dev/SapphireTestTest/DataProvider.php b/tests/php/Dev/SapphireTestTest/DataProvider.php
index 922a46c48dc..bb33b86b48a 100644
--- a/tests/php/Dev/SapphireTestTest/DataProvider.php
+++ b/tests/php/Dev/SapphireTestTest/DataProvider.php
@@ -32,7 +32,7 @@ public static function provideEqualListsWithEmptyList()
                     [],
                 ],
             ],
-            self::provideEqualLists()
+            DataProvider::provideEqualLists()
         );
     }
 
@@ -46,34 +46,34 @@ public static function provideEqualLists()
                 [
                     ['FirstName' => 'Ingo'],
                 ],
-                self::$oneItemList,
+                DataProvider::$oneItemList,
             ],
             'twoParametersOneItem' => [
                 [
                     ['FirstName' => 'Ingo', 'Surname' => 'Schommer'],
                 ],
-                self::$oneItemList,
+                DataProvider::$oneItemList,
             ],
             'oneParameterTwoItems' => [
                 [
                     ['FirstName' => 'Ingo'],
                     ['FirstName' => 'Sam'],
                 ],
-                self::$twoItemList,
+                DataProvider::$twoItemList,
             ],
             'twoParametersTwoItems' => [
                 [
                     ['FirstName' => 'Ingo', 'Surname' => 'Schommer'],
                     ['FirstName' => 'Sam', 'Surname' => 'Minnee'],
                 ],
-                self::$twoItemList,
+                DataProvider::$twoItemList,
             ],
             'mixedParametersTwoItems' => [
                 [
                     ['FirstName' => 'Ingo', 'Surname' => 'Schommer'],
                     ['FirstName' => 'Sam'],
                 ],
-                self::$twoItemList,
+                DataProvider::$twoItemList,
             ],
         ];
     }
@@ -95,28 +95,28 @@ public static function provideNonEqualLists()
                 [
                     ['FirstName' => 'Ingo'],
                 ],
-                self::$twoItemList,
+                DataProvider::$twoItemList,
             ],
             'oneExpectationHasWrontParamter' => [
                 [
                     ['FirstName' => 'IngoXX'],
                     ['FirstName' => 'Sam'],
                 ],
-                self::$twoItemList,
+                DataProvider::$twoItemList,
             ],
             'differentParametersInDifferentItemsAreWrong' => [
                 [
                     ['FirstName' => 'IngoXXX', 'Surname' => 'Schommer'],
                     ['FirstName' => 'Sam', 'Surname' => 'MinneeXXX'],
                 ],
-                self::$twoItemList,
+                DataProvider::$twoItemList,
             ],
             'differentParametersNotMatching' => [
                 [
                     ['FirstName' => 'Daniel', 'Surname' => 'Foo'],
                     ['FirstName' => 'Dan'],
                 ],
-                self::$twoItemList,
+                DataProvider::$twoItemList,
             ],
         ];
     }
@@ -137,21 +137,21 @@ public static function provideNotContainingList()
                 [
                     ['FirstName' => 'Sam'],
                 ],
-                self::$oneItemList,
+                DataProvider::$oneItemList,
             ],
             'twoParametersAreWrong' => [
                 [
                     ['FirstName' => 'IngoXXX', 'Surname' => 'Schommer'],
                     ['FirstName' => 'Sam', 'Surname' => 'MinneeXXX'],
                 ],
-                self::$twoItemList,
+                DataProvider::$twoItemList,
             ],
             'mixedList' => [
                 [
                     ['FirstName' => 'Daniel', 'Surname' => 'Foo'],
                     ['FirstName' => 'Dan'],
                 ],
-                self::$twoItemList,
+                DataProvider::$twoItemList,
             ],
         ];
     }
@@ -164,12 +164,12 @@ public static function provideAllMatchingList()
         return [
             'emptyMatch' => [
                 [],
-                self::$memberList,
+                DataProvider::$memberList,
                 'empty list did not match',
             ],
             'allItemsWithLocaleSet' => [
                 ['Locale' => 'en_US'],
-                self::$memberList,
+                DataProvider::$memberList,
                 'list with Locale set in all items did not match',
             ],
         ];
@@ -181,7 +181,7 @@ public static function provideAllMatchingList()
     public static function provideNotMatchingList()
     {
         return [
-            'notAllItemsHaveLocaleSet' => [['FirstName' => 'Ingo'], self::$memberList],
+            'notAllItemsHaveLocaleSet' => [['FirstName' => 'Ingo'], DataProvider::$memberList],
         ];
     }
 }
diff --git a/tests/php/Logging/DetailedErrorFormatterTest.php b/tests/php/Logging/DetailedErrorFormatterTest.php
index fb36b91d190..1aa90eac2df 100644
--- a/tests/php/Logging/DetailedErrorFormatterTest.php
+++ b/tests/php/Logging/DetailedErrorFormatterTest.php
@@ -43,7 +43,7 @@ public function testFormatWithoutException()
         $this->assertStringContainsString('ERRNO 401', $result, 'Status code was not found in trace');
         $this->assertStringContainsString('Denied', $result, 'Message was not found in trace');
         $this->assertStringContainsString('Line 4 in index.php', $result, 'Line or filename were not found in trace');
-        $this->assertStringContainsString(self::class, $result, 'Backtrace doesn\'t show current test class');
+        $this->assertStringContainsString(DetailedErrorFormatterTest::class, $result, 'Backtrace doesn\'t show current test class');
     }
 
     public function testFormatBatch()
diff --git a/tests/php/ORM/DataListEagerLoadingTest.php b/tests/php/ORM/DataListEagerLoadingTest.php
index 65950a9ae89..13c2460c8f8 100644
--- a/tests/php/ORM/DataListEagerLoadingTest.php
+++ b/tests/php/ORM/DataListEagerLoadingTest.php
@@ -46,7 +46,7 @@ class DataListEagerLoadingTest extends SapphireTest
 
     private const SHOW_QUERIES_RESET = 'SET_TO_THIS_VALUE_WHEN_FINISHED';
 
-    private $showQueries = self::SHOW_QUERIES_RESET;
+    private $showQueries = DataListEagerLoadingTest::SHOW_QUERIES_RESET;
 
     public static function getExtraDataObjects()
     {
@@ -122,7 +122,7 @@ public static function setUpBeforeClass(): void
      */
     private function startCountingSelectQueries(): void
     {
-        if ($this->showQueries !== self::SHOW_QUERIES_RESET) {
+        if ($this->showQueries !== DataListEagerLoadingTest::SHOW_QUERIES_RESET) {
             throw new LogicException('showQueries wasnt reset, you did something wrong');
         }
         $this->showQueries = $_REQUEST['showqueries'] ?? null;
@@ -151,7 +151,7 @@ private function stopCountingSelectQueries(): int
      */
     private function resetShowQueries(): void
     {
-        if ($this->showQueries === self::SHOW_QUERIES_RESET) {
+        if ($this->showQueries === DataListEagerLoadingTest::SHOW_QUERIES_RESET) {
             return;
         }
         if ($this->showQueries) {
@@ -159,7 +159,7 @@ private function resetShowQueries(): void
         } else {
             unset($_REQUEST['showqueries']);
         }
-        $this->showQueries = self::SHOW_QUERIES_RESET;
+        $this->showQueries = DataListEagerLoadingTest::SHOW_QUERIES_RESET;
     }
 
     /**
diff --git a/tests/php/ORM/DataObjectTest/MockDynamicAssignmentDataObject.php b/tests/php/ORM/DataObjectTest/MockDynamicAssignmentDataObject.php
index fc863f512cc..fc8ed726a27 100644
--- a/tests/php/ORM/DataObjectTest/MockDynamicAssignmentDataObject.php
+++ b/tests/php/ORM/DataObjectTest/MockDynamicAssignmentDataObject.php
@@ -30,11 +30,11 @@ class MockDynamicAssignmentDataObject extends DataObject implements TestOnly
     ];
 
     private static $many_many = [
-        'MockManyMany' => self::class,
+        'MockManyMany' => MockDynamicAssignmentDataObject::class,
     ];
 
     private static $belongs_many_many = [
-        'MockBelongsManyMany' => self::class,
+        'MockBelongsManyMany' => MockDynamicAssignmentDataObject::class,
     ];
 
     private static $many_many_extraFields = [
diff --git a/tests/php/ORM/DataObjectTest/TreeNode.php b/tests/php/ORM/DataObjectTest/TreeNode.php
index e497748b29a..43a6535c7d8 100644
--- a/tests/php/ORM/DataObjectTest/TreeNode.php
+++ b/tests/php/ORM/DataObjectTest/TreeNode.php
@@ -25,12 +25,12 @@ class TreeNode extends DataObject implements TestOnly
     ];
 
     private static $has_one = [
-        'Parent' => self::class,
-        'Cycle' => self::class,
+        'Parent' => TreeNode::class,
+        'Cycle' => TreeNode::class,
     ];
 
     private static $has_many = [
-        'Children' => self::class,
+        'Children' => TreeNode::class,
     ];
 
     public function write($showDebug = false, $forceInsert = false, $forceWrite = false, $writeComponents = false)
@@ -51,7 +51,7 @@ public function write($showDebug = false, $forceInsert = false, $forceWrite = fa
     public function resetCounts()
     {
         $update = new SQLUpdate(
-            sprintf('"%s"', self::baseTable()),
+            sprintf('"%s"', TreeNode::baseTable()),
             ['"WriteCount"' => 0]
         );
         $results = $update->execute();
diff --git a/tests/php/ORM/Filters/EndsWithFilterTest.php b/tests/php/ORM/Filters/EndsWithFilterTest.php
index ea5d51d4d2f..d8825d26c4c 100644
--- a/tests/php/ORM/Filters/EndsWithFilterTest.php
+++ b/tests/php/ORM/Filters/EndsWithFilterTest.php
@@ -5,6 +5,7 @@
 use SilverStripe\Dev\SapphireTest;
 use SilverStripe\ORM\Filters\EndsWithFilter;
 use SilverStripe\View\ArrayData;
+use SilverStripe\ORM\Filters\SearchFilter;
 
 class EndsWithFilterTest extends SapphireTest
 {
@@ -267,7 +268,7 @@ public function testMatches(mixed $filterValue, mixed $matchValue, array $modifi
                 }
             }
 
-            EndsWithFilter::config()->set('default_case_sensitive', $caseSensitive);
+            SearchFilter::config()->set('default_case_sensitive', $caseSensitive);
             $filter = new EndsWithFilter();
             $filter->setValue($filterValue);
             $filter->setModifiers($modifiers);
diff --git a/tests/php/ORM/Filters/ExactMatchFilterTest.php b/tests/php/ORM/Filters/ExactMatchFilterTest.php
index aa66b2641ad..61cf04d42df 100644
--- a/tests/php/ORM/Filters/ExactMatchFilterTest.php
+++ b/tests/php/ORM/Filters/ExactMatchFilterTest.php
@@ -9,6 +9,7 @@
 use SilverStripe\ORM\Tests\Filters\ExactMatchFilterTest\Project;
 use SilverStripe\ORM\DataList;
 use SilverStripe\View\ArrayData;
+use SilverStripe\ORM\Filters\SearchFilter;
 
 class ExactMatchFilterTest extends SapphireTest
 {
@@ -313,7 +314,7 @@ public function testMatches(mixed $filterValue, mixed $objValue, array $modifier
                 }
             }
 
-            ExactMatchFilter::config()->set('default_case_sensitive', $caseSensitive);
+            SearchFilter::config()->set('default_case_sensitive', $caseSensitive);
             $filter = new ExactMatchFilter();
             $filter->setValue($filterValue);
             $filter->setModifiers($modifiers);
diff --git a/tests/php/ORM/Filters/PartialMatchFilterTest.php b/tests/php/ORM/Filters/PartialMatchFilterTest.php
index 8f39248b37e..f4ad899427d 100644
--- a/tests/php/ORM/Filters/PartialMatchFilterTest.php
+++ b/tests/php/ORM/Filters/PartialMatchFilterTest.php
@@ -5,6 +5,7 @@
 use SilverStripe\Dev\SapphireTest;
 use SilverStripe\ORM\Filters\PartialMatchFilter;
 use SilverStripe\View\ArrayData;
+use SilverStripe\ORM\Filters\SearchFilter;
 
 class PartialMatchFilterTest extends SapphireTest
 {
@@ -267,7 +268,7 @@ public function testMatches(mixed $filterValue, mixed $objValue, array $modifier
                 }
             }
 
-            PartialMatchFilter::config()->set('default_case_sensitive', $caseSensitive);
+            SearchFilter::config()->set('default_case_sensitive', $caseSensitive);
             $filter = new PartialMatchFilter();
             $filter->setValue($filterValue);
             $filter->setModifiers($modifiers);
diff --git a/tests/php/ORM/Filters/StartsWithFilterTest.php b/tests/php/ORM/Filters/StartsWithFilterTest.php
index 5d4cac344c3..855020f53a6 100644
--- a/tests/php/ORM/Filters/StartsWithFilterTest.php
+++ b/tests/php/ORM/Filters/StartsWithFilterTest.php
@@ -5,6 +5,7 @@
 use SilverStripe\Dev\SapphireTest;
 use SilverStripe\ORM\Filters\StartsWithFilter;
 use SilverStripe\View\ArrayData;
+use SilverStripe\ORM\Filters\SearchFilter;
 
 class StartsWithFilterTest extends SapphireTest
 {
@@ -267,7 +268,7 @@ public function testMatches(mixed $filterValue, mixed $matchValue, array $modifi
                 }
             }
 
-            StartsWithFilter::config()->set('default_case_sensitive', $caseSensitive);
+            SearchFilter::config()->set('default_case_sensitive', $caseSensitive);
             $filter = new StartsWithFilter();
             $filter->setValue($filterValue);
             $filter->setModifiers($modifiers);
diff --git a/tests/php/ORM/MarkedSetTest.php b/tests/php/ORM/MarkedSetTest.php
index 104efe472a1..e2af6cffd55 100644
--- a/tests/php/ORM/MarkedSetTest.php
+++ b/tests/php/ORM/MarkedSetTest.php
@@ -394,7 +394,7 @@ protected function assertTreeContains($html, $nodes, $message = null)
             $xpath .= '/ul/li[@data-id="' . $node->ID . '"]';
         }
         $match = $parser->getByXpath($xpath);
-        self::assertThat((bool)$match, self::isTrue(), $message);
+        MarkedSetTest::assertThat((bool)$match, MarkedSetTest::isTrue(), $message);
     }
 
     /**
@@ -410,7 +410,7 @@ protected function assertTreeNotContains($html, $nodes, $message = null)
             $xpath .= '/ul/li[@data-id="' . $node->ID . '"]';
         }
         $match = $parser->getByXpath($xpath);
-        self::assertThat((bool)$match, self::isFalse(), $message);
+        MarkedSetTest::assertThat((bool)$match, MarkedSetTest::isFalse(), $message);
     }
 
     /**
diff --git a/tests/php/ORM/MySQLiConnectorTest.php b/tests/php/ORM/MySQLiConnectorTest.php
index 0a46b0e915b..8da8b65dd1b 100644
--- a/tests/php/ORM/MySQLiConnectorTest.php
+++ b/tests/php/ORM/MySQLiConnectorTest.php
@@ -62,7 +62,7 @@ public function testConnectionCharsetControl($charset, $defaultCollation)
 
         // Note: we do not need to update the utf charset here because mysqli with newer
         // version of mysql/mariadb still self-reports as 'utf8' rather than 'utf8mb3'
-        // This is unlike self::testConnectionCollationControl()
+        // This is unlike MySQLiConnectorTest::testConnectionCollationControl()
         $this->assertEquals($charset, $cset->charset);
         $this->assertEquals($defaultCollation, $cset->collation);
 
diff --git a/tests/php/ORM/RelatedDataServiceTest.php b/tests/php/ORM/RelatedDataServiceTest.php
index dd1988698c8..93efd4b5e6b 100644
--- a/tests/php/ORM/RelatedDataServiceTest.php
+++ b/tests/php/ORM/RelatedDataServiceTest.php
@@ -109,7 +109,7 @@ public function testUsageHasOneHubExtension()
         // Add DataExtension and reset database so that tables + columns get added
         Hub::add_extension(HubExtension::class);
         DataObject::reset();
-        self::resetDBSchema(true, true);
+        RelatedDataServiceTest::resetDBSchema(true, true);
         //
         $pageTitle = 'My Page that has_one File using HubExtension';
         $myFile = new Node();
@@ -215,7 +215,7 @@ public function testUsageManyManyWithoutBelongsHubExtension()
         // Add DataExtension and reset database so that tables + columns get added
         Hub::add_extension(HubExtension::class);
         DataObject::reset();
-        self::resetDBSchema(true, true);
+        RelatedDataServiceTest::resetDBSchema(true, true);
         //
         $pageTitle = 'My Page that many_many File without belong_many_many Page using HubExtension';
         $myPage = new Hub();
diff --git a/tests/php/ORM/SQLSelectTest/CteRecursiveObject.php b/tests/php/ORM/SQLSelectTest/CteRecursiveObject.php
index 6423b2e12d1..93a15156951 100644
--- a/tests/php/ORM/SQLSelectTest/CteRecursiveObject.php
+++ b/tests/php/ORM/SQLSelectTest/CteRecursiveObject.php
@@ -14,10 +14,10 @@ class CteRecursiveObject extends DataObject implements TestOnly
     ];
 
     private static $has_one = [
-        'Parent' => self::class,
+        'Parent' => CteRecursiveObject::class,
     ];
 
     private static $has_many = [
-        'Children' => self::class . '.Parent',
+        'Children' => CteRecursiveObject::class . '.Parent',
     ];
 }
diff --git a/tests/php/Security/InheritedPermissionsFlusherTest/TestCacheFlusher.php b/tests/php/Security/InheritedPermissionsFlusherTest/TestCacheFlusher.php
index 066ff9ca0fc..a3e59caf6ee 100644
--- a/tests/php/Security/InheritedPermissionsFlusherTest/TestCacheFlusher.php
+++ b/tests/php/Security/InheritedPermissionsFlusherTest/TestCacheFlusher.php
@@ -47,7 +47,7 @@ public function flushMemberCache($memberIDs = null)
         }
 
         if ($memberIDs && is_array($memberIDs)) {
-            foreach (self::$categories as $category) {
+            foreach (TestCacheFlusher::$categories as $category) {
                 foreach ($memberIDs as $memberID) {
                     $key = $this->generateCacheKey($category, $memberID);
                     $this->cache->delete($key);
diff --git a/tests/php/Security/InheritedPermissionsTest/TestPermissionNode.php b/tests/php/Security/InheritedPermissionsTest/TestPermissionNode.php
index f769a4802d9..1621f40ed85 100644
--- a/tests/php/Security/InheritedPermissionsTest/TestPermissionNode.php
+++ b/tests/php/Security/InheritedPermissionsTest/TestPermissionNode.php
@@ -23,7 +23,7 @@ class TestPermissionNode extends DataObject implements TestOnly
     ];
 
     private static $has_one = [
-        "Parent" => self::class,
+        "Parent" => TestPermissionNode::class,
     ];
 
     private static $table_name = 'InheritedPermissionsTest_TestPermissionNode';
diff --git a/tests/php/Security/InheritedPermissionsTest/UnstagedNode.php b/tests/php/Security/InheritedPermissionsTest/UnstagedNode.php
index db45f0831fa..ab816bbd17c 100644
--- a/tests/php/Security/InheritedPermissionsTest/UnstagedNode.php
+++ b/tests/php/Security/InheritedPermissionsTest/UnstagedNode.php
@@ -23,7 +23,7 @@ class UnstagedNode extends DataObject implements TestOnly
     ];
 
     private static $has_one = [
-        "Parent" => self::class,
+        "Parent" => UnstagedNode::class,
     ];
 
     private static $table_name = 'InheritedPermissionsTest_UnstagedNode';
diff --git a/tests/php/View/RequirementsTest.php b/tests/php/View/RequirementsTest.php
index c2582de9e14..30838d4eba9 100644
--- a/tests/php/View/RequirementsTest.php
+++ b/tests/php/View/RequirementsTest.php
@@ -62,7 +62,7 @@ public function testExternalUrls()
         $backend->css('//scheme-relative.example.com/test.css');
         $backend->css('http://www.mydomain.com:3000/test.css');
 
-        $html = $backend->includeInHTML(self::$html_template);
+        $html = $backend->includeInHTML(RequirementsTest::$html_template);
 
         $this->assertStringContainsString('http://www.mydomain.com/test.js', $html, 'Load external javascript URL');
         $this->assertStringContainsString('https://www.mysecuredomain.com/test.js', $html, 'Load external secure javascript URL');
@@ -89,7 +89,7 @@ public function testResolveCSSReferencesDisabled()
             ]
         );
 
-        $backend->includeInHTML(self::$html_template);
+        $backend->includeInHTML(RequirementsTest::$html_template);
 
         // we get the file path here
         $allCSS = $backend->getCSS();
@@ -137,7 +137,7 @@ public function testResolveCSSReferences()
             ]
         );
 
-        $backend->includeInHTML(self::$html_template);
+        $backend->includeInHTML(RequirementsTest::$html_template);
 
         // we get the file path here
         $allCSS = $backend->getCSS();
@@ -389,7 +389,7 @@ public function testCustomType()
             [ 'type' => 'application/json' ]
         );
         $backend->javascript('javascript/RequirementsTest_b.js');
-        $result = $backend->includeInHTML(self::$html_template);
+        $result = $backend->includeInHTML(RequirementsTest::$html_template);
         $this->assertMatchesRegularExpression(
             '#<script type="application/json" src=".*/javascript/RequirementsTest_a.js#',
             $result
@@ -410,7 +410,7 @@ public function testCombinedJavascript()
         $combinedFileName = '/_combinedfiles/RequirementsTest_bc-2a55d56.js';
         $combinedFilePath = TestAssetStore::base_path() . $combinedFileName;
 
-        $html = $backend->includeInHTML(self::$html_template);
+        $html = $backend->includeInHTML(RequirementsTest::$html_template);
 
         /* COMBINED JAVASCRIPT FILE IS INCLUDED IN HTML HEADER */
         $this->assertMatchesRegularExpression(
@@ -461,7 +461,7 @@ public function testCombinedJavascript()
         /** @var Requirements_Backend $backend */
         $backend = Injector::inst()->create(Requirements_Backend::class);
         $this->setupCombinedNonrequiredRequirements($backend);
-        $html = $backend->includeInHTML(self::$html_template);
+        $html = $backend->includeInHTML(RequirementsTest::$html_template);
 
         /* COMBINED JAVASCRIPT FILE IS INCLUDED IN HTML HEADER */
         $this->assertMatchesRegularExpression(
@@ -511,7 +511,7 @@ public function testCombinedJavascriptAsyncDefer()
         $combinedFileName = '/_combinedfiles/RequirementsTest_bc-2a55d56.js';
         $combinedFilePath = TestAssetStore::base_path() . $combinedFileName;
 
-        $html = $backend->includeInHTML(self::$html_template);
+        $html = $backend->includeInHTML(RequirementsTest::$html_template);
 
         /* ASYNC IS INCLUDED IN SCRIPT TAG */
         $this->assertMatchesRegularExpression(
@@ -585,7 +585,7 @@ public function testCombinedJavascriptAsyncDefer()
 
         $this->setupCombinedRequirementsJavascriptAsyncDefer($backend, false, true);
 
-        $html = $backend->includeInHTML(self::$html_template);
+        $html = $backend->includeInHTML(RequirementsTest::$html_template);
 
         /* DEFER IS INCLUDED IN SCRIPT TAG */
         $this->assertMatchesRegularExpression(
@@ -659,7 +659,7 @@ public function testCombinedJavascriptAsyncDefer()
 
         $this->setupCombinedRequirementsJavascriptAsyncDefer($backend, true, true);
 
-        $html = $backend->includeInHTML(self::$html_template);
+        $html = $backend->includeInHTML(RequirementsTest::$html_template);
 
         /* ASYNC/DEFER IS INCLUDED IN SCRIPT TAG */
         $this->assertMatchesRegularExpression(
@@ -745,7 +745,7 @@ public function testCombinedCss()
             ]
         );
 
-        $html = $backend->includeInHTML(self::$html_template);
+        $html = $backend->includeInHTML(RequirementsTest::$html_template);
 
         $this->assertMatchesRegularExpression(
             '/href=".*\/print\-69ce614\.css/',
@@ -781,7 +781,7 @@ public function testCombinedCss()
             ]
         );
 
-        $html = $backend->includeInHTML(self::$html_template);
+        $html = $backend->includeInHTML(RequirementsTest::$html_template);
         $this->assertMatchesRegularExpression(
             '/href=".*\/style\-8011538\.css/',
             $html,
@@ -801,7 +801,7 @@ public function testBlockedCombinedJavascript()
         $backend->block('RequirementsTest_bc.js');
 
         clearstatcache(); // needed to get accurate file_exists() results
-        $html = $backend->includeInHTML(self::$html_template);
+        $html = $backend->includeInHTML(RequirementsTest::$html_template);
         $this->assertFileDoesNotExist($combinedFilePath);
         $this->assertDoesNotMatchRegularExpression(
             '/src=".*\/RequirementsTest_bc\.js/',
@@ -816,7 +816,7 @@ public function testBlockedCombinedJavascript()
         $combinedFileName2 = '/_combinedfiles/RequirementsTest_bc-3748f67.js'; // SHA1 without file b included
         $combinedFilePath2 = TestAssetStore::base_path() . $combinedFileName2;
         clearstatcache(); // needed to get accurate file_exists() results
-        $backend->includeInHTML(self::$html_template);
+        $backend->includeInHTML(RequirementsTest::$html_template);
         $this->assertFileExists($combinedFilePath2);
         $this->assertStringNotContainsString(
             "alert('b')",
@@ -856,7 +856,7 @@ public function testArgsInUrls()
 
         $backend->javascript('javascript/RequirementsTest_a.js?test=1&test=2&test=3');
         $backend->css('css/RequirementsTest_a.css?test=1&test=2&test=3');
-        $html = $backend->includeInHTML(self::$html_template);
+        $html = $backend->includeInHTML(RequirementsTest::$html_template);
 
         /* Javascript has correct path */
         $this->assertMatchesRegularExpression(
@@ -1406,7 +1406,7 @@ public function testSriAttributes()
         // Tests attribute appending AND lowercase string conversion
         $backend->customScriptWithAttributes("//TEST", ['type' => 'module', 'crossorigin' => 'Anonymous']);
         $backend->css('css/RequirementsTest_a.css', null, ['integrity' => 'def', 'crossorigin' => 'anonymous']);
-        $html = $backend->includeInHTML(self::$html_template);
+        $html = $backend->includeInHTML(RequirementsTest::$html_template);
 
         /* Javascript has correct attributes */
         $this->assertMatchesRegularExpression(
@@ -1447,7 +1447,7 @@ public function testUniquenessID()
         $backend->customCSS("Override", 42);
         $backend->insertHeadTags("<span>Override</span>", 42);
 
-        $html = $backend->includeInHTML(self::$html_template);
+        $html = $backend->includeInHTML(RequirementsTest::$html_template);
 
         /* customScript is overwritten by customScriptWithAttributes */
         $this->assertMatchesRegularExpression(
diff --git a/tests/php/View/SSViewerTest/LevelTestData.php b/tests/php/View/SSViewerTest/LevelTestData.php
index b45008b9f2d..017d47e74e8 100644
--- a/tests/php/View/SSViewerTest/LevelTestData.php
+++ b/tests/php/View/SSViewerTest/LevelTestData.php
@@ -32,6 +32,6 @@ public function forLoop($number)
 
     public function forWith($number)
     {
-        return new self($number);
+        return new LevelTestData($number);
     }
 }
diff --git a/tests/php/i18n/i18nTest/TestObject.php b/tests/php/i18n/i18nTest/TestObject.php
index 3d7e7df6af5..279b30a202f 100644
--- a/tests/php/i18n/i18nTest/TestObject.php
+++ b/tests/php/i18n/i18nTest/TestObject.php
@@ -11,13 +11,13 @@ class TestObject implements TestOnly, i18nEntityProvider
 
     public static function my_translatable_property()
     {
-        return _t(__CLASS__ . ".my_translatable_property", self::$my_translatable_property);
+        return _t(__CLASS__ . ".my_translatable_property", TestObject::$my_translatable_property);
     }
 
     public function provideI18nEntities()
     {
         return [
-            __CLASS__ . ".my_translatable_property" => self::$my_translatable_property,
+            __CLASS__ . ".my_translatable_property" => TestObject::$my_translatable_property,
         ];
     }
 }
diff --git a/thirdparty/php-peg/Compiler.php b/thirdparty/php-peg/Compiler.php
index 07a08c7217e..536acece11c 100644
--- a/thirdparty/php-peg/Compiler.php
+++ b/thirdparty/php-peg/Compiler.php
@@ -37,7 +37,7 @@ class PHPWriter {
 	static $varid = 0 ;
 
 	function varid() {
-		return '_' . (self::$varid++) ;
+		return '_' . (Compiler::$varid++) ;
 	}
 
 	function function_name( $str ) {
@@ -255,7 +255,7 @@ abstract class TokenExpressionable extends TokenTerminal {
 	static $expression_rx = '/ \$(\w+) | { \$(\w+) } /x';
 
 	function contains_expression( $value ){
-		return preg_match(self::$expression_rx, $value ?? '');
+		return preg_match(Compiler::$expression_rx, $value ?? '');
 	}
 
 	function expression_replace($matches) {
@@ -263,7 +263,7 @@ function expression_replace($matches) {
 	}
 	
 	function match_code( $value ) {
-		$value = preg_replace_callback(self::$expression_rx, array($this, 'expression_replace'), $value ?? '');
+		$value = preg_replace_callback(Compiler::$expression_rx, array($this, 'expression_replace'), $value ?? '');
 		return parent::match_code($value);
 	}
 }
@@ -295,7 +295,7 @@ static function escape( $rx ) {
 	}
 	
 	function __construct( $value ) {
-		parent::__construct('rx', self::escape($value));
+		parent::__construct('rx', Compiler::escape($value));
 	}
 
 	function match_code( $value ) {
@@ -504,7 +504,7 @@ function __construct($parser, $lines) {
 		
 		// Find the first line (if any) that's an attached function definition. Can skip first line (unless this block is malformed)
 		for ($i = 1; $i < count($lines ?? []); $i++) {
-			if (preg_match(self::$function_rx, $lines[$i] ?? '')) break;
+			if (preg_match(Compiler::$function_rx, $lines[$i] ?? '')) break;
 		}
 		
 		// Then split into the two parts
@@ -513,7 +513,7 @@ function __construct($parser, $lines) {
 		
 		// Parse out the spec
 		$spec = implode("\n", $spec);
-		if (!preg_match(self::$rule_rx, $spec ?? '', $specmatch)) user_error('Malformed rule spec ' . $spec, E_USER_ERROR);
+		if (!preg_match(Compiler::$rule_rx, $spec ?? '', $specmatch)) user_error('Malformed rule spec ' . $spec, E_USER_ERROR);
 		
 		$this->name = $specmatch['name'];
 		
@@ -525,7 +525,7 @@ function __construct($parser, $lines) {
 		$this->arguments = array();
 		
 		if ($specmatch['arguments']) {
-			preg_match_all(self::$argument_rx, $specmatch['arguments'] ?? '', $arguments, PREG_SET_ORDER);
+			preg_match_all(Compiler::$argument_rx, $specmatch['arguments'] ?? '', $arguments, PREG_SET_ORDER);
 			
 			foreach ($arguments as $argument){
 				$this->arguments[trim($argument[1])] = trim($argument[2] ?? '');
@@ -542,7 +542,7 @@ function __construct($parser, $lines) {
 			if (!$this->extends) user_error('Replace matcher, but not on an extends rule', E_USER_ERROR);
 			
 			$this->replacements = array();
-			preg_match_all(self::$replacement_rx, $specmatch['rule'] ?? '', $replacements, PREG_SET_ORDER);
+			preg_match_all(Compiler::$replacement_rx, $specmatch['rule'] ?? '', $replacements, PREG_SET_ORDER);
 			
 			$rule = $this->extends->rule;
 			
@@ -565,7 +565,7 @@ function __construct($parser, $lines) {
 
 		foreach( $funcs as $line ) {
 			/* Handle function definitions */
-			if ( preg_match( self::$function_rx, $line ?? '', $func_match, 0 ) ) {
+			if ( preg_match( Compiler::$function_rx, $line ?? '', $func_match, 0 ) ) {
 				$active_function = $func_match[1];
 				$this->functions[$active_function] = $func_match[2] . PHP_EOL;
 			}
@@ -627,7 +627,7 @@ function tokenize( $str, &$tokens, $o = 0 ) {
 				$o += strlen( $match[0] ?? '' ) ;
 			}
 			/* Handle regexs */
-			elseif ( preg_match( self::$rx_rx, $sub ?? '', $match ) ) {
+			elseif ( preg_match( Compiler::$rx_rx, $sub ?? '', $match ) ) {
 				$tokens[] = $t = new TokenRegex( $match[0] ) ; $pending->apply_if_present( $t ) ;
 				$o += strlen( $match[0] ?? '' ) ;
 			}
@@ -819,9 +819,9 @@ static function create_parser( $match ) {
 		$indent = $match[1];
 		
 		/* Get the parser name for this block */
-		if     ($class = trim($match[2] ?? '')) self::$currentClass = $class;
-		elseif (self::$currentClass)      $class = self::$currentClass;
-		else                              $class = self::$currentClass = 'Anonymous Parser';
+		if     ($class = trim($match[2] ?? '')) Compiler::$currentClass = $class;
+		elseif (Compiler::$currentClass)      $class = Compiler::$currentClass;
+		else                              $class = Compiler::$currentClass = 'Anonymous Parser';
 		
 		/* Check for pragmas */
 		if (strpos($class ?? '', '!') === 0) {
@@ -836,16 +836,16 @@ static function create_parser( $match ) {
 						'*/'
 					)) . PHP_EOL;
 				case '!debug':
-					self::$debug = true;
+					Compiler::$debug = true;
 					return '';
 			}
 			
 			throw new Exception("Unknown pragma $class encountered when compiling parser");
 		}
 		
-		if (!isset(self::$parsers[$class])) self::$parsers[$class] = new RuleSet();
+		if (!isset(Compiler::$parsers[$class])) Compiler::$parsers[$class] = new RuleSet();
 		
-		return self::$parsers[$class]->compile($indent, $match[3]);
+		return Compiler::$parsers[$class]->compile($indent, $match[3]);
 	}
 
 	static function compile( $string ) {
@@ -869,7 +869,7 @@ static function cli( $args ) {
 		else {
 			$fname = ( $args[1] == '-' ? 'php://stdin' : $args[1] ) ;
 			$string = file_get_contents( $fname ?? '' ) ;
-			$string = self::compile( $string ) ;
+			$string = Compiler::compile( $string ) ;
 
 			if ( !empty( $args[2] ) && $args[2] != '-' ) {
 				file_put_contents( $args[2] ?? '', $string ) ;