Part of the error for lack of type annotations can give a hint that doesn't work

[glandium]

Given the following code:

fn foo<const N: usize>(_: impl std::fmt::Display) -> [usize; N] {
    [0; N]
}

fn main() {
    let f = foo("foo");
}

The current output is:

error[E0282]: type annotations needed for `[usize; _]`
 --> src/main.rs:6:13
  |
6 |     let f = foo("foo");
  |         -   ^^^ cannot infer the value of const parameter `N` declared on the function `foo`
  |         |
  |         consider giving `f` the explicit type `[usize; _]`, where the type parameter `N` is specified
  |
help: consider specifying the const argument
  |
6 |     let f = foo::<N>("foo");
  |             ^^^^^^^^

The first half is correct, but the problem is that final suggestion. If you try it:

fn foo<const N: usize>(_: impl std::fmt::Display) -> [usize; N] {
    [0; N]
}

fn main() {
    let f = foo::<2>("foo");
}

you get another error because the suggestion can't work because of the impl std::fmt::Display:

error[E0632]: cannot provide explicit generic arguments when `impl Trait` is used in argument position
 --> src/main.rs:6:19
  |
6 |     let f = foo::<2>("foo");
  |                   ^ explicit generic argument not allowed