Add minimal reproducer for ICE in #6179

Author: Y-Nak

tests/ui/use_self.fixed

@@ -458,3 +458,21 @@ mod nested_paths {
         }
     }
 }
+
+/// This is a minimal reproducer for ICE in https://github.com/rust-lang/rust-clippy/pull/6179.
+/// The ICE is mainly caused by using `hir_ty_to_ty`. See the discussion in the PR for details.
+mod pr6179_ice {
+    struct Foo {}
+
+    impl Foo {
+        fn foo() -> Self {
+            impl Foo {
+                fn bar() {}
+            }
+
+            let _: _ = 1;
+
+            Self {}
+        }
+    }
+}

tests/ui/use_self.rs

@@ -458,3 +458,21 @@ mod nested_paths {
         }
     }
 }
+
+/// This is a minimal reproducer for ICE in https://github.com/rust-lang/rust-clippy/pull/6179.
+/// The ICE is mainly caused by using `hir_ty_to_ty`. See the discussion in the PR for details.
+mod pr6179_ice {
+    struct Foo {}
+
+    impl Foo {
+        fn foo() -> Self {
+            impl Foo {
+                fn bar() {}
+            }
+
+            let _: _ = 1;
+
+            Self {}
+        }
+    }
+}