rust/src/test/ui/issues/issue-42312.stderr
Dan Aloni 07e7823c01 pretty: trim paths of unique symbols
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.
2020-09-02 22:26:37 +03:00

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error[E0277]: the size for values of type `<Self as Deref>::Target` cannot be known at compilation time
--> $DIR/issue-42312.rs:4:12
|
LL | fn baz(_: Self::Target) where Self: Deref {}
| ^ doesn't have a size known at compile-time
|
= help: the trait `Sized` is not implemented for `<Self as Deref>::Target`
= help: unsized locals are gated as an unstable feature
help: consider further restricting the associated type
|
LL | fn baz(_: Self::Target) where Self: Deref, <Self as Deref>::Target: Sized {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: function arguments must have a statically known size, borrowed types always have a known size
|
LL | fn baz(_: &Self::Target) where Self: Deref {}
| ^
error[E0277]: the size for values of type `(dyn ToString + 'static)` cannot be known at compilation time
--> $DIR/issue-42312.rs:8:10
|
LL | pub fn f(_: dyn ToString) {}
| ^ doesn't have a size known at compile-time
|
= help: the trait `Sized` is not implemented for `(dyn ToString + 'static)`
= help: unsized locals are gated as an unstable feature
help: function arguments must have a statically known size, borrowed types always have a known size
|
LL | pub fn f(_: &dyn ToString) {}
| ^
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0277`.