f0c93117ed
When encountering trait bound errors that satisfy some heuristics that tell us that the relevant trait for the user comes from the root obligation and not the current obligation, we use the root predicate for the main message. This allows to talk about "X doesn't implement Pattern<'_>" over the most specific case that just happened to fail, like "char doesn't implement Fn(&mut char)" in `tests/ui/traits/suggest-dereferences/root-obligation.rs` The heuristics are: - the type of the leaf predicate is (roughly) the same as the type from the root predicate, as a proxy for "we care about the root" - the leaf trait and the root trait are different, so as to avoid talking about `&mut T: Trait` and instead remain talking about `T: Trait` instead - the root trait is not `Unsize`, as to avoid talking about it in `tests/ui/coercion/coerce-issue-49593-box-never.rs`. ``` error[E0277]: the trait bound `&char: Pattern<'_>` is not satisfied --> $DIR/root-obligation.rs:6:38 | LL | .filter(|c| "aeiou".contains(c)) | -------- ^ the trait `Fn<(char,)>` is not implemented for `&char`, which is required by `&char: Pattern<'_>` | | | required by a bound introduced by this call | = note: required for `&char` to implement `FnOnce<(char,)>` = note: required for `&char` to implement `Pattern<'_>` note: required by a bound in `core::str::<impl str>::contains` --> $SRC_DIR/core/src/str/mod.rs:LL:COL help: consider dereferencing here | LL | .filter(|c| "aeiou".contains(*c)) | + ``` Fix #79359, fix #119983, fix #118779, cc #118415 (the suggestion needs to change).
80 lines
3.5 KiB
Plaintext
80 lines
3.5 KiB
Plaintext
error[E0277]: the trait bound `impl Future<Output = ()>: Coroutine<_>` is not satisfied
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--> $DIR/coroutine-not-future.rs:31:21
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LL | takes_coroutine(async_fn());
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| --------------- ^^^^^^^^^^ the trait `Coroutine<_>` is not implemented for `impl Future<Output = ()>`
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| |
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| required by a bound introduced by this call
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note: required by a bound in `takes_coroutine`
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--> $DIR/coroutine-not-future.rs:18:39
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LL | fn takes_coroutine<ResumeTy>(_g: impl Coroutine<ResumeTy, Yield = (), Return = ()>) {}
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `takes_coroutine`
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error[E0277]: the trait bound `impl Future<Output = ()>: Coroutine<_>` is not satisfied
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--> $DIR/coroutine-not-future.rs:33:21
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LL | takes_coroutine(returns_async_block());
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| --------------- ^^^^^^^^^^^^^^^^^^^^^ the trait `Coroutine<_>` is not implemented for `impl Future<Output = ()>`
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| |
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| required by a bound introduced by this call
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note: required by a bound in `takes_coroutine`
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--> $DIR/coroutine-not-future.rs:18:39
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LL | fn takes_coroutine<ResumeTy>(_g: impl Coroutine<ResumeTy, Yield = (), Return = ()>) {}
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `takes_coroutine`
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error[E0277]: the trait bound `{async block@$DIR/coroutine-not-future.rs:35:21: 35:29}: Coroutine<_>` is not satisfied
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--> $DIR/coroutine-not-future.rs:35:21
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LL | takes_coroutine(async {});
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| --------------- ^^^^^^^^ the trait `Coroutine<_>` is not implemented for `{async block@$DIR/coroutine-not-future.rs:35:21: 35:29}`
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| |
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| required by a bound introduced by this call
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note: required by a bound in `takes_coroutine`
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--> $DIR/coroutine-not-future.rs:18:39
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LL | fn takes_coroutine<ResumeTy>(_g: impl Coroutine<ResumeTy, Yield = (), Return = ()>) {}
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `takes_coroutine`
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error[E0277]: `impl Coroutine<Yield = (), Return = ()>` is not a future
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--> $DIR/coroutine-not-future.rs:39:18
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LL | takes_future(returns_coroutine());
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| ------------ ^^^^^^^^^^^^^^^^^^^ `impl Coroutine<Yield = (), Return = ()>` is not a future
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| required by a bound introduced by this call
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= help: the trait `Future` is not implemented for `impl Coroutine<Yield = (), Return = ()>`
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note: required by a bound in `takes_future`
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--> $DIR/coroutine-not-future.rs:17:26
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LL | fn takes_future(_f: impl Future<Output = ()>) {}
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| ^^^^^^^^^^^^^^^^^^^ required by this bound in `takes_future`
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error[E0277]: `{coroutine@$DIR/coroutine-not-future.rs:41:18: 41:23}` is not a future
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--> $DIR/coroutine-not-future.rs:41:18
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LL | takes_future(|ctx| {
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| _____------------_^
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| | |
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| | required by a bound introduced by this call
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LL | |
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LL | | ctx = yield ();
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LL | | });
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| |_____^ `{coroutine@$DIR/coroutine-not-future.rs:41:18: 41:23}` is not a future
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= help: the trait `Future` is not implemented for `{coroutine@$DIR/coroutine-not-future.rs:41:18: 41:23}`
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note: required by a bound in `takes_future`
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--> $DIR/coroutine-not-future.rs:17:26
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LL | fn takes_future(_f: impl Future<Output = ()>) {}
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| ^^^^^^^^^^^^^^^^^^^ required by this bound in `takes_future`
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error: aborting due to 5 previous errors
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For more information about this error, try `rustc --explain E0277`.
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