diff --git a/compiler/rustc_passes/messages.ftl b/compiler/rustc_passes/messages.ftl
index a4ef065ea2c83..81c7b42b105b5 100644
--- a/compiler/rustc_passes/messages.ftl
+++ b/compiler/rustc_passes/messages.ftl
@@ -290,6 +290,9 @@ passes_duplicate_lang_item_crate_depends =
.first_definition_path = first definition in `{$orig_crate_name}` loaded from {$orig_path}
.second_definition_path = second definition in `{$crate_name}` loaded from {$path}
+passes_enum_variant_same_name =
+ it is impossible to refer to the {$descr} `{$dead_name}` because it is shadowed by this enum variant with the same name
+
passes_export_name =
attribute should be applied to a free function, impl method or static
.label = not a free function, impl method or static
diff --git a/compiler/rustc_passes/src/dead.rs b/compiler/rustc_passes/src/dead.rs
index e597c819a3aae..4257d8e8d16bd 100644
--- a/compiler/rustc_passes/src/dead.rs
+++ b/compiler/rustc_passes/src/dead.rs
@@ -14,7 +14,7 @@ use rustc_errors::MultiSpan;
use rustc_hir::def::{CtorOf, DefKind, Res};
use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId};
use rustc_hir::intravisit::{self, Visitor};
-use rustc_hir::{self as hir, Node, PatKind, QPath, TyKind};
+use rustc_hir::{self as hir, ImplItem, ImplItemKind, Node, PatKind, QPath, TyKind};
use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
use rustc_middle::middle::privacy::Level;
use rustc_middle::query::Providers;
@@ -936,7 +936,9 @@ enum ShouldWarnAboutField {
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
enum ReportOn {
+ /// Report on something that hasn't got a proper name to refer to
TupleField,
+ /// Report on something that has got a name, which could be a field but also a method
NamedField,
}
@@ -1061,6 +1063,31 @@ impl<'tcx> DeadVisitor<'tcx> {
None
};
+ let enum_variants_with_same_name = dead_codes
+ .iter()
+ .filter_map(|dead_item| {
+ if let Node::ImplItem(ImplItem {
+ kind: ImplItemKind::Fn(..) | ImplItemKind::Const(..),
+ ..
+ }) = tcx.hir_node_by_def_id(dead_item.def_id)
+ && let Some(impl_did) = tcx.opt_parent(dead_item.def_id.to_def_id())
+ && let DefKind::Impl { of_trait: false } = tcx.def_kind(impl_did)
+ && let ty::Adt(maybe_enum, _) = tcx.type_of(impl_did).skip_binder().kind()
+ && maybe_enum.is_enum()
+ && let Some(variant) =
+ maybe_enum.variants().iter().find(|i| i.name == dead_item.name)
+ {
+ Some(crate::errors::EnumVariantSameName {
+ descr: tcx.def_descr(dead_item.def_id.to_def_id()),
+ dead_name: dead_item.name,
+ variant_span: tcx.def_span(variant.def_id),
+ })
+ } else {
+ None
+ }
+ })
+ .collect();
+
let diag = match report_on {
ReportOn::TupleField => {
let tuple_fields = if let Some(parent_id) = parent_item
@@ -1114,6 +1141,7 @@ impl<'tcx> DeadVisitor<'tcx> {
name_list,
parent_info,
ignored_derived_impls,
+ enum_variants_with_same_name,
},
};
diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index 74ce92624bd49..74c89f0c698b5 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -1478,6 +1478,9 @@ pub(crate) enum MultipleDeadCodes<'tcx> {
participle: &'tcx str,
name_list: DiagSymbolList,
#[subdiagnostic]
+ // only on DeadCodes since it's never a problem for tuple struct fields
+ enum_variants_with_same_name: Vec<EnumVariantSameName<'tcx>>,
+ #[subdiagnostic]
parent_info: Option<ParentInfo<'tcx>>,
#[subdiagnostic]
ignored_derived_impls: Option<IgnoredDerivedImpls>,
@@ -1498,6 +1501,15 @@ pub(crate) enum MultipleDeadCodes<'tcx> {
},
}
+#[derive(Subdiagnostic)]
+#[note(passes_enum_variant_same_name)]
+pub(crate) struct EnumVariantSameName<'tcx> {
+ #[primary_span]
+ pub variant_span: Span,
+ pub dead_name: Symbol,
+ pub descr: &'tcx str,
+}
+
#[derive(Subdiagnostic)]
#[label(passes_parent_info)]
pub(crate) struct ParentInfo<'tcx> {
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 0000000000000..d172ceb41dde4
--- /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 0000000000000..e3c1a4c81a491
--- /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
+