Prevent mixed|null

vimeo · Feb 7, 2024 · 0546788 · 0546788
1 parent 4a5dbca
commit 0546788
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diff --git a/src/Psalm/Type/MutableUnion.php b/src/Psalm/Type/MutableUnion.php
@@ -23,6 +23,7 @@
 use Psalm\Type\Atomic\TTemplateParamClass;
 use Psalm\Type\Atomic\TTrue;
 
+use function array_key_exists;
 use function count;
 use function get_class;
 use function get_object_vars;
@@ -269,6 +270,12 @@ public function setTypes(array $types): self
      */
     public function addType(Atomic $type): self
     {
+        $mixed = new TMixed();
+        $mixedKey = $mixed->getKey();
+        if ($type->getKey() === $mixedKey || array_key_exists($mixedKey, $this->types)) {
+            $this->types = [$mixedKey => $mixed];
+            return $this;
+        }
         $this->types[$type->getKey()] = $type;
 
         if ($type instanceof TLiteralString) {

diff --git a/tests/ArgTest.php b/tests/ArgTest.php
@@ -355,6 +355,20 @@ function foo($a, ...$b) {}
 
                     var_caller("foo");',
             ],
+            'mixedNullable' => [
+                'code' => '<?php
+                    class A {
+                        public function __construct(public mixed $default = null) {
+                        }
+                    }
+                    $a = new A;
+                    $_v = $a->default;',
+                'assertions' => [
+                    '$_v===' => 'mixed',
+                ],
+                'ignored_issues' => [],
+                'php_version' => '8.0',
+            ],
         ];
     }