Trait "constructor" methods don't get coercions?

[scottmcm]

Working on #41414, I found this error that surprised me:

#![feature(try_trait)]
fn main() {
    let my_string = "hello".to_string();
    let _x: Result<&str, i32> = {
        std::ops::Try::from_ok(&my_string)
        //~^ type mismatch resolving `<std::result::Result<&str, i32> as std::ops::Try>::Ok == &std::string::String`
    };
}

I'd expected that it'd work, since the trait method is -> Self, and the result of the block is fully constrained, and writing it this way of course works:

<Result<&str, i32> as std::ops::Try>::from_ok(&my_string)

Of course, this may well just be a normal "mixing coercions and inference is annoying" case that people who understand inference wouldn't have expected to work 😅

[cjgillot]

The diagnostic is now correctly normalized

error[E0271]: type mismatch resolving `<Result<&str, i32> as Try>::Output == &String`
 --> <source>:5:9
  |
5 |         std::ops::Try::from_output(&my_string)
  |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `str`, found struct `String`
  |
  = note: expected reference `&str`
             found reference `&String`