bors a6ece56152 Auto merge of #86400 - FabianWolff:issue-85735, r=estebank ... Remove invalid suggestion involving `Fn` trait bound This pull request closes #85735. The actual issue is a duplicate of #21974, but #85735 contains a further problem, which is an invalid suggestion if `Fn`/`FnMut`/`FnOnce` trait bounds are involved: The suggestion code checks whether the trait bound ends with `>` to determine whether it has any generic arguments, but the `Fn*` traits have a special syntax for generic arguments that doesn't involve angle brackets. The example given in #85735: ```rust trait Foo {} impl<'a, 'b, T> Foo for T where T: FnMut(&'a ()), T: FnMut(&'b ()), { } ``` currently produces: ``` error[E0283]: type annotations needed --> src/lib.rs:4:8 | 4 | T: FnMut(&'a ()), | ^^^^^^^^^^^^^ cannot infer type for type parameter `T` | = note: cannot satisfy `T: FnMut<(&'a (),)>` help: consider specifying the type arguments in the function call | 4 | T: FnMut(&'a ())::<Self, Args>, | ^^^^^^^^^^^^^^ error: aborting due to previous error ``` which is incorrect, because there is no function call, and applying the suggestion would lead to a parse error. With my changes, I get: ``` error[E0283]: type annotations needed --> test.rs:4:8 | 4 | T: FnMut(&'a ()), | ^^^^^^^^^^^^^ cannot infer type for type parameter `T` | ::: [...]/library/core/src/ops/function.rs:147:1 | 147 | pub trait FnMut<Args>: FnOnce<Args> { | ----------------------------------- required by this bound in `FnMut` | = note: cannot satisfy `T: FnMut<(&'a (),)>` error: aborting due to previous error ``` i.e. I have added a check to prevent the invalid suggestion from being issued for `Fn*` bounds, while the underlying issue #21974 remains for now.		2021-08-03 19:48:54 +00:00
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src	Auto merge of #86400 - FabianWolff:issue-85735, r=estebank	2021-08-03 19:48:54 +00:00
Cargo.toml	rfc3052: Remove authors field from Cargo manifests	2021-07-29 14:56:05 -07:00