`r#` stripped from raw idents in lint and `type annotations needed` error

[olegnn]

This code

fn r<r#trait>() {}

fn main() {
    r();
}

(Playground)

Gives incorrect warning and error for type declared using raw identifiers:

warning: type parameter `trait` should have an upper camel case name
 --> src/main.rs:1:6
  |
1 | fn r<r#trait>() {}
  |      ^^^^^^^ help: convert the identifier to upper camel case: `Trait`
  |
  = note: `#[warn(non_camel_case_types)]` on by default

error[E0282]: type annotations needed
 --> src/main.rs:4:5
  |
4 |     r();
  |     ^ cannot infer type for type parameter `trait`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0282`.
error: could not compile `playground`.

NOTE: This is about the diagnostics not including the r# in each case.

[jonas-schievink]

These seem correct to me, since r# is just an escape for keywords, not part of the actual name. Otherwise #[no_mangle] should also create a symbol called r#something.

[Centril]

The type checking error here is correct. You have a type parameter that is passed no argument so it gets an inference variable that is never solved.

As for the warning, that is correct too. It is responding to the fact that the keyword is lower case, which is correct behavior. If you use fn r<r#Fn>() {} the warning goes away.

[olegnn]

@Centril issue isn't about incorrect type checking but about incorrect messages

type parameter `fn` should have an upper camel case name

and

cannot infer type for type parameter `fn`

[olegnn]

should be r#fn both

[Centril]

Oh I see; now I get what you're saying; it's a diagnostics issue, not a behavior issue. Yes, that seems right.

[olegnn]

I will change type parameter names to make them look more obvious.