Don't check trait impls

Author: Anthony Huang

clippy_lints/src/self_named_constructor.rs

@@ -1,7 +1,7 @@
 use clippy_utils::diagnostics::span_lint;
 use clippy_utils::return_ty;
 use clippy_utils::ty::{contains_adt_constructor, contains_ty};
-use rustc_hir::{ImplItem, ImplItemKind, Node};
+use rustc_hir::{Impl, ImplItem, ImplItemKind, ItemKind, Node};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
@@ -51,13 +51,21 @@ impl<'tcx> LateLintPass<'tcx> for SelfNamedConstructor {
         let item = cx.tcx.hir().expect_item(parent);
         let self_ty = cx.tcx.type_of(item.def_id);
         let ret_ty = return_ty(cx, impl_item.hir_id());
+
+        // Do not check trait impls
+        if matches!(item.kind, ItemKind::Impl(Impl { of_trait: Some(_), .. })) {
+            return;
+        }
+
+        // Ensure method is constructor-like
         if let Some(self_adt) = self_ty.ty_adt_def() {
             if !contains_adt_constructor(ret_ty, self_adt) {
                 return;
             }
         } else if !contains_ty(ret_ty, self_ty) {
             return;
         }
+
         if_chain! {
             if let Some(self_def) = self_ty.ty_adt_def();
             if let Some(self_local_did) = self_def.did.as_local();

tests/ui/self_named_constructor.rs

@@ -35,7 +35,17 @@ impl ShouldNotSpawnWithTrait {
     }
 }
 
+// Same trait name and same type name should not spawn the lint
 #[derive(Default)]
 pub struct Default;
 
+trait TraitSameTypeName {
+    fn should_not_spawn() -> Self;
+}
+impl TraitSameTypeName for ShouldNotSpawn {
+    fn should_not_spawn() -> Self {
+        ShouldNotSpawn
+    }
+}
+
 fn main() {}

tests/ui/self_named_constructor.stderr

@@ -8,13 +8,5 @@ LL | |     }
    |
    = note: `-D clippy::self-named-constructor` implied by `-D warnings`
 
-error: constructor `default` has the same name as the type
-  --> $DIR/self_named_constructor.rs:38:10
-   |
-LL | #[derive(Default)]
-   |          ^^^^^^^
-   |
-   = note: this error originates in the derive macro `Default` (in Nightly builds, run with -Z macro-backtrace for more info)
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error