E0308 hint suggests adding a return type to a closure

Code

fn main() {
    b"abc".iter().for_each(|x| dbg!(x))
}

Current output

error[E0308]: mismatched types
 --> src/main.rs:2:32
  |
2 |     b"abc".iter().for_each(|x| dbg!(x))
  |                               -^^^^^^^ expected `()`, found `&u8`
  |                               |
  |                               help: try adding a return type: `-> &u8`
  |

Desired output

error[E0308]: mismatched types
 --> src/main.rs:2:32
  |
2 |     b"abc".iter().for_each(|x| dbg!(x))
  |                               -^^^^^^^ expected `()`, found `&u8`
  |                               |
  |                               help: try ignoring this value: `_ = dbg!(x)`

Rationale and extra context

closures have their return type inferred if not specified, so adding a return type to a closure will never fix a type mismatch error.

Other cases

No response

Rust Version

1.80.0

Anything else?

No response

Reproduce the E0308 diagnostic with the closure example on Rust 1.80.0, then trace the compiler diagnostic that suggests adding a closure return type. Done means this case suggests ignoring the value with _ = dbg!(x) instead, without changing unrelated diagnostics.