clean up issue-21950 (dyn trait cast without assoc type at the cast)

tests/ui/traits/cast-as-dyn-trait-wo-assoc-type-issue-21950.rs

@@ -0,0 +1,19 @@
+//! Tests that compiler yields error E0191 when value with existing trait implementation
+//! is cast as same `dyn` trait without specifying associated type at the cast.
+//!
+//! # Context
+//! Original issue: https://github.com/rust-lang/rust/issues/21950
+
+trait Add<Rhs=Self> {
+ type Output;
+}
+
+impl Add for i32 {
+ type Output = i32;
+}
+
+fn main() {
+ let x = &10 as &dyn Add<i32, Output = i32>; //OK
+ let x = &10 as &dyn Add;
+ //~^ ERROR E0191
+}

tests/ui/issues/issue-21950.stderr → tests/ui/traits/cast-as-dyn-trait-wo-assoc-type-issue-21950.stderr

@@ -1,5 +1,5 @@
 error[E0191]: the value of the associated type `Output` in `Add` must be specified
- --> $DIR/issue-21950.rs:10:25
+ --> $DIR/cast-as-dyn-trait-wo-assoc-type-issue-21950.rs:17:25
  |
 LL | type Output;
  | ----------- `Output` defined here