07e7823c01
If a symbol name can only be imported from one place for a type, and as long as it was not glob-imported anywhere in the current crate, we can trim its printed path and print only the name. This has wide implications on error messages with types, for example, shortening `std::vec::Vec` to just `Vec`, as long as there is no other `Vec` importable anywhere. This adds a new '-Z trim-diagnostic-paths=false' option to control this feature. On the good path, with no diagnosis printed, we should try to avoid issuing this query, so we need to prevent trimmed_def_paths query on several cases. This change also relies on a previous commit that differentiates between `Debug` and `Display` on various rustc types, where the latter is trimmed and presented to the user and the former is not.
45 lines
1.7 KiB
Plaintext
45 lines
1.7 KiB
Plaintext
error[E0277]: the trait bound `U: Copy` is not satisfied
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--> $DIR/wf-fn-where-clause.rs:8:24
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LL | trait ExtraCopy<T:Copy> { }
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| ---- required by this bound in `ExtraCopy`
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LL |
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LL | fn foo<T,U>() where T: ExtraCopy<U>
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| ^^^^^^^^^^^^ the trait `Copy` is not implemented for `U`
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help: consider further restricting type parameter `U`
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LL | fn foo<T,U>() where T: ExtraCopy<U>, U: Copy
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| ^^^^^^^^^
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error[E0277]: the size for values of type `(dyn Copy + 'static)` cannot be known at compilation time
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--> $DIR/wf-fn-where-clause.rs:12:16
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LL | fn bar() where Vec<dyn Copy>:, {}
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| ^^^^^^^^^^^^^ doesn't have a size known at compile-time
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...
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LL | struct Vec<T> {
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| - required by this bound in `Vec`
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= help: the trait `Sized` is not implemented for `(dyn Copy + 'static)`
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help: you could relax the implicit `Sized` bound on `T` if it were used through indirection like `&T` or `Box<T>`
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--> $DIR/wf-fn-where-clause.rs:16:12
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LL | struct Vec<T> {
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| ^ this could be changed to `T: ?Sized`...
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LL | t: T,
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| - ...if indirection was used here: `Box<T>`
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error[E0038]: the trait `Copy` cannot be made into an object
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--> $DIR/wf-fn-where-clause.rs:12:16
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LL | fn bar() where Vec<dyn Copy>:, {}
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| ^^^^^^^^^^^^^ the trait `Copy` cannot be made into an object
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= note: the trait cannot be made into an object because it requires `Self: Sized`
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error: aborting due to 3 previous errors
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Some errors have detailed explanations: E0038, E0277.
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For more information about an error, try `rustc --explain E0038`.
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