Rollup merge of #142406 - jdonszelmann:dead-code-enum-variant, r=WaffleLapkin

Note when enum variants shadow an associated function

r? ``@WaffleLapkin``

Closes rust-lang/rust#142263

2 files changed, 50 insertions, 0 deletions

diff --git a/tests/ui/enum/dead-code-associated-function.rs b/tests/ui/enum/dead-code-associated-function.rs
new file mode 100644
index 00000000000..d172ceb41dd
--- /dev/null
+++ b/tests/ui/enum/dead-code-associated-function.rs
@@ -0,0 +1,20 @@
+//@ check-pass
+#![warn(dead_code)]
+
+enum E {
+    F(),
+    C(),
+}
+
+impl E {
+    #[expect(non_snake_case)]
+    fn F() {}
+    //~^ WARN: associated items `F` and `C` are never used
+
+    const C: () = ();
+}
+
+fn main() {
+    let _: E = E::F();
+    let _: E = E::C();
+}
diff --git a/tests/ui/enum/dead-code-associated-function.stderr b/tests/ui/enum/dead-code-associated-function.stderr
new file mode 100644
index 00000000000..e3c1a4c81a4
--- /dev/null
+++ b/tests/ui/enum/dead-code-associated-function.stderr
@@ -0,0 +1,30 @@
+warning: associated items `F` and `C` are never used
+  --> $DIR/dead-code-associated-function.rs:11:8
+   |
+LL | impl E {
+   | ------ associated items in this implementation
+LL |     #[expect(non_snake_case)]
+LL |     fn F() {}
+   |        ^
+...
+LL |     const C: () = ();
+   |           ^
+   |
+note: it is impossible to refer to the associated function `F` because it is shadowed by this enum variant with the same name
+  --> $DIR/dead-code-associated-function.rs:5:5
+   |
+LL |     F(),
+   |     ^
+note: it is impossible to refer to the associated constant `C` because it is shadowed by this enum variant with the same name
+  --> $DIR/dead-code-associated-function.rs:6:5
+   |
+LL |     C(),
+   |     ^
+note: the lint level is defined here
+  --> $DIR/dead-code-associated-function.rs:2:9
+   |
+LL | #![warn(dead_code)]
+   |         ^^^^^^^^^
+
+warning: 1 warning emitted
+