item_name_repetitions: exclude enum variants with identical path components (#14619)

fix #13637

As suggested in the PR above, we should not lint enum variants
containing matching path names.

changelog: [`item_name_repetitions`]: exclude enum variants with
identical path components

Author: Manishearth

clippy_lints/src/item_name_repetitions.rs

@@ -5,7 +5,7 @@ use clippy_utils::macros::span_is_local;
 use clippy_utils::source::is_present_in_source;
 use clippy_utils::str_utils::{camel_case_split, count_match_end, count_match_start, to_camel_case, to_snake_case};
 use rustc_data_structures::fx::FxHashSet;
-use rustc_hir::{EnumDef, FieldDef, Item, ItemKind, OwnerId, Variant, VariantData};
+use rustc_hir::{EnumDef, FieldDef, Item, ItemKind, OwnerId, QPath, TyKind, Variant, VariantData};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::impl_lint_pass;
 use rustc_span::symbol::Symbol;
@@ -405,6 +405,7 @@ fn check_enum_start(cx: &LateContext<'_>, item_name: &str, variant: &Variant<'_>
     if count_match_start(item_name, name).char_count == item_name_chars
         && name.chars().nth(item_name_chars).is_some_and(|c| !c.is_lowercase())
         && name.chars().nth(item_name_chars + 1).is_some_and(|c| !c.is_numeric())
+        && !check_enum_tuple_path_match(name, variant.data)
     {
         span_lint_hir(
             cx,
@@ -420,7 +421,9 @@ fn check_enum_end(cx: &LateContext<'_>, item_name: &str, variant: &Variant<'_>)
     let name = variant.ident.name.as_str();
     let item_name_chars = item_name.chars().count();
 
-    if count_match_end(item_name, name).char_count == item_name_chars {
+    if count_match_end(item_name, name).char_count == item_name_chars
+        && !check_enum_tuple_path_match(name, variant.data)
+    {
         span_lint_hir(
             cx,
             ENUM_VARIANT_NAMES,
@@ -431,6 +434,27 @@ fn check_enum_end(cx: &LateContext<'_>, item_name: &str, variant: &Variant<'_>)
     }
 }
 
+/// Checks if an enum tuple variant contains a single field
+/// whose qualified path contains the variant's name.
+fn check_enum_tuple_path_match(variant_name: &str, variant_data: VariantData<'_>) -> bool {
+    // Only check single-field tuple variants
+    let VariantData::Tuple(fields, ..) = variant_data else {
+        return false;
+    };
+    if fields.len() != 1 {
+        return false;
+    }
+    // Check if field type is a path and contains the variant name
+    match fields[0].ty.kind {
+        TyKind::Path(QPath::Resolved(_, path)) => path
+            .segments
+            .iter()
+            .any(|segment| segment.ident.name.as_str() == variant_name),
+        TyKind::Path(QPath::TypeRelative(_, segment)) => segment.ident.name.as_str() == variant_name,
+        _ => false,
+    }
+}
+
 impl LateLintPass<'_> for ItemNameRepetitions {
     fn check_item_post(&mut self, _cx: &LateContext<'_>, item: &Item<'_>) {
         let Some(_ident) = item.kind.ident() else { return };

tests/ui/enum_variants.rs

@@ -220,4 +220,19 @@ mod issue11494 {
     }
 }
 
+mod encapsulated {
+    mod types {
+        pub struct FooError;
+        pub struct BarError;
+        pub struct BazError;
+    }
+
+    enum Error {
+        FooError(types::FooError),
+        BarError(types::BarError),
+        BazError(types::BazError),
+        Other,
+    }
+}
+
 fn main() {}