Relax a test to permit warnings to be emitted, too.

[oli-obk]

This change is necessary to allow rustc to actually start emitting the warning about the unused mut

See the test failure in rust-lang/rust#120550 (comment) for where this happens.

[rustbot]

r? @weihanglo

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[weihanglo]

Before rust-lang/rust#120550:

error[E0308]: mismatched types
 --> src/lib.rs:8:35
  |
8 |                     let _x: u32 = "a";
  |                             ---   ^^^ expected `u32`, found `&str`
  |                             |
  |                             expected due to this

For more information about this error, try `rustc --explain E0308`.
error: could not compile `foo` (lib test) due to 1 previous error
warning: build failed, waiting for other jobs to finish...
error: could not compile `foo` (lib) due to 1 previous error

This is what we'll have after rust-lang/rust#120550:

error[E0308]: mismatched types
Error:  --> src/lib.rs:8:35
  |
8 |                     let _x: u32 = "a";
  |                             ---   ^^^ expected `u32`, found `&str`
  |                             |
  |                             expected due to this

warning: variable does not need to be mutable
Warning:  --> src/lib.rs:3:25
  |
3 |                     let mut x = 3;
  |                         ----^
  |                         |
  |                         help: remove this `mut`
  |
  = note: `#[warn(unused_mut)]` on by default

For more information about this error, try `rustc --explain E0308`.
warning: `foo` (lib) generated 1 warning
error: could not compile `foo` (lib) due to 1 previous error; 1 warning emitted
warning: build failed, waiting for other jobs to finish...
warning: `foo` (lib test) generated 1 warning (1 duplicate)
error: could not compile `foo` (lib test) due to 1 previous error; 1 warning emitted

I wonder if we could

Suggested change

	.with_stderr_line_without(
	&["[ERROR] could not compile `foo` (lib) due to 1 previous error"],
	&[],
	)
	.with_stderr_contains("[ERROR] could not compile `foo` (lib) due to 1 previous error[..]")

And have a TODO for updating this after rust-lang/rust#120550 landed. (though not required since it's not the point of this test)

[oli-obk]

yep, that works.

[weihanglo]

@bors r+

Thanks! I'll update the submodule shortly.

[bors]

📌 Commit e60678f has been approved by weihanglo

It is now in the queue for this repository.

[bors]

⌛ Testing commit e60678f with merge ccc84cc...

[bors]

☀️ Test successful - checks-actions
Approved by: weihanglo
Pushing ccc84cc to master...