Bad suggestion for _ in associated const #82158
Description
As noted in #81914, given the following:
fn main() {} struct MyStruct; trait Test { } impl Test for MyStruct { const TEST: fn() -> _ = 42; }we emit
error[E0438]: const `TEST` is not a member of trait `Test` --> main_test.rs:10:5 | 10 | const TEST: fn() -> _ = 42; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ not a member of trait `Test` error[E0121]: the type placeholder `_` is not allowed within types on item signatures --> main_test.rs:10:25 | 10 | const TEST: fn() -> _ = 42; | ^ | | | not allowed in type signatures | help: use type parameters instead: `T` Follow up to #81885.