diff --git a/tests/ui/attributes/outer-mod-attr-applies-only-to-first.rs b/tests/ui/attributes/outer-mod-attr-applies-only-to-first.rs
new file mode 100644
index 0000000000000..ec521c1afb518
--- /dev/null
+++ b/tests/ui/attributes/outer-mod-attr-applies-only-to-first.rs
@@ -0,0 +1,16 @@
+//! Regression test to check that outer attributes applied to the first module item is applied to
+//! its attached module item only, and not also to other subsequent module items
+//!
+//! Commit: <https://github.com/rust-lang/rust/commit/7aee9f7b56f8d96f9444ebb1d06e32e024b81974>
+
+//@ check-pass
+//@ compile-flags: --cfg=first
+//@ no-auto-check-cfg
+
+#[cfg(first)]
+mod hello {}
+
+#[cfg(not_set)]
+mod hello {}
+
+fn main() {}
diff --git a/tests/ui/dupe-first-attr.rs b/tests/ui/dupe-first-attr.rs
deleted file mode 100644
index c254df050c153..0000000000000
--- a/tests/ui/dupe-first-attr.rs
+++ /dev/null
@@ -1,25 +0,0 @@
-//@ run-pass
-
-// Regression test for a problem with the first mod attribute
-// being applied to every mod
-
-
-#[cfg(target_os = "linux")]
-mod hello {}
-
-#[cfg(target_os = "macos")]
-mod hello {}
-
-#[cfg(target_os = "windows")]
-mod hello {}
-
-#[cfg(target_os = "freebsd")]
-mod hello {}
-
-#[cfg(target_os = "dragonfly")]
-mod hello {}
-
-#[cfg(target_os = "android")]
-mod hello {}
-
-fn main() {}
diff --git a/tests/ui/duplicate_entry_error.rs b/tests/ui/duplicate_entry_error.rs
deleted file mode 100644
index 5a25802c6e789..0000000000000
--- a/tests/ui/duplicate_entry_error.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-//@ normalize-stderr: "loaded from .*libstd-.*.rlib" -> "loaded from SYSROOT/libstd-*.rlib"
-// note-pattern: first defined in crate `std`.
-
-// Test for issue #31788 and E0152
-
-#![feature(lang_items)]
-
-extern crate core;
-
-use core::panic::PanicInfo;
-
-#[lang = "panic_impl"]
-fn panic_impl(info: &PanicInfo) -> ! {
-//~^ ERROR: found duplicate lang item `panic_impl`
-    loop {}
-}
-
-fn main() {}
diff --git a/tests/ui/error-codes/E0152-duplicate-lang-items.rs b/tests/ui/error-codes/E0152-duplicate-lang-items.rs
new file mode 100644
index 0000000000000..089810b1ad249
--- /dev/null
+++ b/tests/ui/error-codes/E0152-duplicate-lang-items.rs
@@ -0,0 +1,20 @@
+//! Validates the correct printing of E0152 in the case of duplicate "lang_item" function
+//! definitions.
+//!
+//! Issue: <https://github.com/rust-lang/rust/issues/31788>
+
+//@ error-pattern: first defined in crate `std`
+//@ normalize-stderr: "loaded from .*libstd-.*.rlib" -> "loaded from SYSROOT/libstd-*.rlib"
+#![feature(lang_items)]
+
+extern crate core;
+
+use core::panic::PanicInfo;
+
+#[lang = "panic_impl"]
+fn panic_impl(info: &PanicInfo) -> ! {
+    //~^ ERROR: found duplicate lang item `panic_impl`
+    loop {}
+}
+
+fn main() {}
diff --git a/tests/ui/duplicate_entry_error.stderr b/tests/ui/error-codes/E0152-duplicate-lang-items.stderr
similarity index 70%
rename from tests/ui/duplicate_entry_error.stderr
rename to tests/ui/error-codes/E0152-duplicate-lang-items.stderr
index 958e9c7527d8c..3c3d64322f3cd 100644
--- a/tests/ui/duplicate_entry_error.stderr
+++ b/tests/ui/error-codes/E0152-duplicate-lang-items.stderr
@@ -1,5 +1,5 @@
 error[E0152]: found duplicate lang item `panic_impl`
-  --> $DIR/duplicate_entry_error.rs:13:1
+  --> $DIR/E0152-duplicate-lang-items.rs:15:1
    |
 LL | / fn panic_impl(info: &PanicInfo) -> ! {
 LL | |
@@ -7,9 +7,9 @@ LL | |     loop {}
 LL | | }
    | |_^
    |
-   = note: the lang item is first defined in crate `std` (which `duplicate_entry_error` depends on)
+   = note: the lang item is first defined in crate `std` (which `E0152_duplicate_lang_items` depends on)
    = note: first definition in `std` loaded from SYSROOT/libstd-*.rlib
-   = note: second definition in the local crate (`duplicate_entry_error`)
+   = note: second definition in the local crate (`E0152_duplicate_lang_items`)
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/duplicate-label-E0381-issue-129274.rs b/tests/ui/error-codes/E0381-duplicated-label.rs
similarity index 68%
rename from tests/ui/duplicate-label-E0381-issue-129274.rs
rename to tests/ui/error-codes/E0381-duplicated-label.rs
index b2156e630c87f..84a85caa65df3 100644
--- a/tests/ui/duplicate-label-E0381-issue-129274.rs
+++ b/tests/ui/error-codes/E0381-duplicated-label.rs
@@ -1,3 +1,6 @@
+//! Regression test for duplicated label in E0381 error message.
+//!
+//! Issue: <https://github.com/rust-lang/rust/issues/129274>
 fn main() {
     fn test() {
         loop {
diff --git a/tests/ui/duplicate-label-E0381-issue-129274.stderr b/tests/ui/error-codes/E0381-duplicated-label.stderr
similarity index 91%
rename from tests/ui/duplicate-label-E0381-issue-129274.stderr
rename to tests/ui/error-codes/E0381-duplicated-label.stderr
index 7f8bddb17c5a8..36e6d966f09d1 100644
--- a/tests/ui/duplicate-label-E0381-issue-129274.stderr
+++ b/tests/ui/error-codes/E0381-duplicated-label.stderr
@@ -1,5 +1,5 @@
 error[E0381]: used binding `blah` is possibly-uninitialized
-  --> $DIR/duplicate-label-E0381-issue-129274.rs:8:33
+  --> $DIR/E0381-duplicated-label.rs:11:33
    |
 LL |             let blah: Option<String>;
    |                 ---- binding declared here but left uninitialized