Calling a trait method as a free function yields odd diagnostics

Given the following code: playground

trait Foo {
    fn bar() {}
}

fn main() {
    Foo::bar();
}

The current output is:

error[E0283]: type annotations needed
 --> src/main.rs:4:5
  |
4 |     Foo::bar();
  |     ^^^^^^^^ cannot infer type
  |
  = note: cannot satisfy `_: Foo`

Ideally the output should look like:

Cannot call trait method as a free function. It needs an actual type to be implemented on for it to be called.

For bonus points: The trait is currently not callable since it's not implemented for anything. It needs to actually be implemented. "It looks like you're trying to call this trait method, but nothing implements it."

@rustbot

@rustbot claim

Add ui test for rust-lang#98938

This is addressed by #98028. The error message is now

error[E0790]: cannot call associated function on trait without specifying the corresponding `impl` type
 --> test.rs:6:5
  |
2 |     fn bar() {}
  |     ----------- `Foo::bar` defined here
...
6 |     Foo::bar();
  |     ^^^^^^^^ cannot call associated function of trait

@obeis

Heads up @obeis #99308

I'm gonna close this since it seems like it's fixed. Feel free to file another bug if there are additional changes desired 😄

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Calling a trait method as a free function yields odd diagnostics #98938

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Calling a trait method as a free function yields odd diagnostics #98938

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obeis commented on Jul 10, 2022

aticu commented on Jul 19, 2022

compiler-errors commented on Jul 19, 2022

compiler-errors commented on Jul 19, 2022

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