fix recursion in case of type_alias_impl_trait

See rust-lang#10068 (comment) for details

-- original PR description of rust-lang#10068 --

fixes rust-lang#10041

Prevent recursion into Self when it's a generic parameter. Added regression test from example in rust-lang#10041.

- \[x] Followed [lint naming conventions][lint_naming] - **N/A**
- \[x] Added passing UI tests (including committed `.stderr` file)
- \[x] `cargo test` passes locally
- \[x] Executed `cargo dev update_lints` - **N/A**
- \[x] Added lint documentation - **N/A**
- \[x] Run `cargo dev fmt`

changelog: [`new-ret-no-self`] Fix segmentation fault caused when generic parameter defaults to `Self` and is unspecified. For example, `fn uh_oh(&self) -> impl PartialOrd { ... }` has a hidden `Rhs=Self` as the generic parameter for `PartialOrd`.

clippy_utils/src/ty.rs

@@ -91,7 +91,7 @@ pub fn contains_ty_adt_constructor_opaque<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'
                                 .types()
                                 .skip(1) // Skip the implicit `Self` generic parameter
                                 .filter(|inner_ty| *inner_ty != ty) // Skip any other `Self` generic parameters
-                                .any(|ty| contains_ty_adt_constructor_opaque(cx, ty, needle))
+                                .any(|ty| ty == needle || ty.ty_adt_def() == needle.ty_adt_def())
                             {
                                 return true;
                             }
@@ -100,7 +100,7 @@ pub fn contains_ty_adt_constructor_opaque<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'
                         // so we check the term for `U`.
                         ty::PredicateKind::Clause(ty::Clause::Projection(projection_predicate)) => {
                             if let ty::TermKind::Ty(ty) = projection_predicate.term.unpack() {
-                                if contains_ty_adt_constructor_opaque(cx, ty, needle) {
+                                if ty == needle || ty.ty_adt_def() == needle.ty_adt_def() {
                                     return true;
                                 }
                             };

tests/ui/new_ret_no_self.rs

@@ -1,3 +1,4 @@
+#![feature(type_alias_impl_trait)]
 #![warn(clippy::new_ret_no_self)]
 #![allow(dead_code)]
 
@@ -411,3 +412,15 @@ mod issue10041 {
         }
     }
 }
+
+mod issue10041_TAIT {
+    type X = impl std::ops::Add<Output = X>;
+
+    struct Foo;
+
+    impl Foo {
+        fn new() -> X {
+            return 1;
+        }
+    }
+}

tests/ui/new_ret_no_self.stderr

@@ -1,5 +1,5 @@
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:49:5
+  --> $DIR/new_ret_no_self.rs:50:5
    |
 LL | /     pub fn new(_: String) -> impl R<Item = u32> {
 LL | |         S3
@@ -9,88 +9,86 @@ LL | |     }
    = note: `-D clippy::new-ret-no-self` implied by `-D warnings`
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:81:5
+  --> $DIR/new_ret_no_self.rs:82:5
    |
 LL | /     pub fn new() -> u32 {
 LL | |         unimplemented!();
 LL | |     }
    | |_____^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:90:5
+  --> $DIR/new_ret_no_self.rs:91:5
    |
 LL | /     pub fn new(_: String) -> u32 {
 LL | |         unimplemented!();
 LL | |     }
    | |_____^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:126:5
+  --> $DIR/new_ret_no_self.rs:127:5
    |
 LL | /     pub fn new() -> (u32, u32) {
 LL | |         unimplemented!();
 LL | |     }
    | |_____^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:153:5
+  --> $DIR/new_ret_no_self.rs:154:5
    |
 LL | /     pub fn new() -> *mut V {
 LL | |         unimplemented!();
 LL | |     }
    | |_____^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:171:5
+  --> $DIR/new_ret_no_self.rs:172:5
    |
 LL | /     pub fn new() -> Option<u32> {
 LL | |         unimplemented!();
 LL | |     }
    | |_____^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:224:9
+  --> $DIR/new_ret_no_self.rs:225:9
    |
 LL |         fn new() -> String;
    |         ^^^^^^^^^^^^^^^^^^^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:236:9
+  --> $DIR/new_ret_no_self.rs:237:9
    |
 LL |         fn new(_: String) -> String;
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:271:9
+  --> $DIR/new_ret_no_self.rs:272:9
    |
 LL | /         fn new() -> (u32, u32) {
 LL | |             unimplemented!();
 LL | |         }
    | |_________^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:298:9
+  --> $DIR/new_ret_no_self.rs:299:9
    |
 LL | /         fn new() -> *mut V {
 LL | |             unimplemented!();
 LL | |         }
    | |_________^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:368:9
+  --> $DIR/new_ret_no_self.rs:369:9
    |
 LL | /         fn new(t: T) -> impl Into<i32> {
 LL | |             1
 LL | |         }
    | |_________^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:389:9
+  --> $DIR/new_ret_no_self.rs:390:9
    |
 LL | /         fn new(t: T) -> impl Trait2<(), i32> {
 LL | |             unimplemented!()
 LL | |         }
    | |_________^
 
-error: aborting due to 12 previous errors
-