Bad error message when closure parameter type can't be inferred

[ParadoxSpiral]

The code

fn main() {
    let a = None;
    let c = |a: Option<_>| println!("{:?}", a);
    c(a)
}

errors with

error[E0282]: type annotations needed
 --> src/main.rs:3:14
  |
2 |     let a = None;
  |         - consider giving `a` a type
3 |     let c = |a: Option<_>| println!("{:?}", a);
  |              ^ consider giving this closure parameter a type

which should be something like

error[E0282]: type annotations needed
 --> src/main.rs:3:14
  |
2 |     let a = None;
  |         - consider giving `a` a type
3 |     let c = |a: Option<_>| println!("{:?}", a);
  |                        ^ cannot infer type for `_`

[sinesc]

The suggestion "consider giving this closure parameter a type" can also be quite frustrating when the parameter would also require lifetime annotations, see #22340

[estebank]

Current output:

error[E0282]: type annotations needed for `std::option::Option<_>`
 --> src/main.rs:4:14
  |
4 |     let c = |a: Option<_>| println!("{:?}", a);
  |              ^ consider giving this closure parameter the explicit type `std::option::Option<_>`, where the type parameter `T` is specified

and

error[E0282]: type annotations needed for `std::option::Option<T>`
 --> src/main.rs:4:14
  |
4 |     let c = |a| println!("{:?}", a);
  |              ^ consider giving this closure parameter the explicit type `std::option::Option<T>`, where the type parameter `T` is specified

I believe this can be closed as there's little improvement to be had in the medium term.