Add regression test

Author: oli-obk

Diff for: tests/ui/methods/opaque_param_in_ufc.rs

@@ -0,0 +1,30 @@
+#![feature(type_alias_impl_trait)]
+struct Foo<T>(T);
+
+impl Foo<u32> {
+    fn method() {}
+    fn method2(self) {}
+}
+
+type Bar = impl Sized;
+
+fn bar() -> Bar {
+    42_u32
+}
+
+impl Foo<Bar> {
+    fn foo() -> Bar {
+        Self::method();
+        //~^ ERROR: no function or associated item named `method` found for struct `Foo<Bar>`
+        Foo::<Bar>::method();
+        //~^ ERROR: no function or associated item named `method` found for struct `Foo<Bar>`
+        let x = Foo(bar());
+        Foo::method2(x);
+        let x = Self(bar());
+        Self::method2(x);
+        //~^ ERROR: no function or associated item named `method2` found for struct `Foo<Bar>`
+        todo!()
+    }
+}
+
+fn main() {}

Diff for: tests/ui/methods/opaque_param_in_ufc.stderr

@@ -0,0 +1,36 @@
+error[E0599]: no function or associated item named `method` found for struct `Foo<Bar>` in the current scope
+  --> $DIR/opaque_param_in_ufc.rs:17:15
+   |
+LL | struct Foo<T>(T);
+   | ------------- function or associated item `method` not found for this struct
+...
+LL |         Self::method();
+   |               ^^^^^^ function or associated item not found in `Foo<Bar>`
+   |
+   = note: the function or associated item was found for
+           - `Foo<u32>`
+
+error[E0599]: no function or associated item named `method` found for struct `Foo<Bar>` in the current scope
+  --> $DIR/opaque_param_in_ufc.rs:19:21
+   |
+LL | struct Foo<T>(T);
+   | ------------- function or associated item `method` not found for this struct
+...
+LL |         Foo::<Bar>::method();
+   |                     ^^^^^^ function or associated item not found in `Foo<Bar>`
+   |
+   = note: the function or associated item was found for
+           - `Foo<u32>`
+
+error[E0599]: no function or associated item named `method2` found for struct `Foo<Bar>` in the current scope
+  --> $DIR/opaque_param_in_ufc.rs:24:15
+   |
+LL | struct Foo<T>(T);
+   | ------------- function or associated item `method2` not found for this struct
+...
+LL |         Self::method2(x);
+   |               ^^^^^^^ function or associated item not found in `Foo<Bar>`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0599`.