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.
* Make some run-pass or check-pass
* Use `#![allow(incomplete_features)]`
* Update FIXMEs now that some of the issues have been addressed
* Add regression tests
I took most tests that were testing only for match exhaustiveness,
pattern refutability or match arm reachability, and put them in
the same test folder.
Disallow double trailing newlines in tidy
This wasn't done previously in https://github.com/rust-lang/rust/pull/47064#issuecomment-354533010 as it affected too many files, but I think it's best to fix it now so that the number of files with double trailing newlines doesn't keep increasing.
r? kennytm
```
error[E0004]: non-exhaustive patterns: type `X` is non-empty
--> file.rs:9:11
|
1 | / enum X {
2 | | A,
| | - variant not covered
3 | | B,
| | - variant not covered
4 | | C,
| | - variant not covered
5 | | }
| |_- `X` defined here
...
9 | match x {
| ^
|
= help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
error[E0004]: non-exhaustive patterns: `B` and `C` not covered
--> file.rs:11:11
|
1 | / enum X {
2 | | A,
3 | | B,
4 | | C,
| | - not covered
5 | | }
| |_- `X` defined here
...
11 | match x {
| ^ patterns `C` not covered
```
When a match expression doesn't have patterns covering every variant,
point at the enum's definition span. On a best effort basis, point at the
variant(s) that are missing. This does not handle the case when the missing
pattern is due to a field's enum variants:
```
enum E1 {
A,
B,
C,
}
enum E2 {
A(E1),
B,
}
fn foo() {
match E2::A(E1::A) {
E2::A(E1::B) => {}
E2::B => {}
}
//~^ ERROR `E2::A(E1::A)` and `E2::A(E1::C)` not handled
}
```
Unify look between match with no arms and match with some missing patterns.
Fix#37518.
Improve type mismatch error messages
Closes#56115.
Replace "integral variable" with "integer" and replace "floating-point variable" with "floating-point number" to make the message less confusing.
TODO the book and clippy needs to be changed accordingly later.
r? @varkor
It looks like we tend to use angle-brackets around the placeholder in
the few other places we use `Applicability::HasPlaceholders`, but that
would be confusing here, so ...
