error[E0214]: parenthesized type parameters may only be used with a `Fn` trait --> $DIR/issue-32995-2.rs:2:22 | LL | { fn f() {} } | ^^^^^^^^ only `Fn` traits may use parentheses error[E0214]: parenthesized type parameters may only be used with a `Fn` trait --> $DIR/issue-32995-2.rs:5:29 | LL | { fn f() -> impl ::std::marker()::Send { } } | ^^^^^^^^ only `Fn` traits may use parentheses error[E0214]: parenthesized type parameters may only be used with a `Fn` trait --> $DIR/issue-32995-2.rs:12:13 | LL | impl ::std::marker()::Copy for X {} | ^^^^^^^^ only `Fn` traits may use parentheses error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0214`.