ignore uninhabited non-exhaustive variant fields
Fixes#65157.
This PR modifies the uninhabitedness checking so that the fields of
a non-exhaustive variant (which is not local) are ignored if they are
uninhabited. This is an improvement over the previous behaviour which
considered all non-local non-exhaustive variants useful because
unreachable patterns are now detected.
r? @arielb1
cc @varkor
Add by-value iterator for arrays
This adds an iterator that can iterate over arrays by value, yielding all elements by value. However, **this PR does _not_ add a corresponding `IntoIterator` impl for arrays**. The `IntoIterator` impl needs some discussion about backwards-compatibility that should take place in a separate PR. With this patch, this code should work (but there is currently still a bug):
```rust
#![feature(array_value_iter)]
use std::array::IntoIter;
let arr = [1, 2, 3];
for x in IntoIter::new(arr) {
println!("{}", x);
}
```
**TODO**:
- [x] Get initial feedback
- [x] Add tests
- [x] Figure out why stage1 produces weird bugs ([comment](https://github.com/rust-lang/rust/pull/62959#issuecomment-516016524))
- [x] Add UI tests as mentioned [here](https://github.com/rust-lang/rust/pull/62959#discussion_r307061894) (will do that soon-ish)
- [x] Fix [this new bug](https://github.com/rust-lang/rust/pull/62959#issuecomment-544732159)
**Notes for reviewers**
- Is the use of `MaybeUninit` correct here? I think it has to be used due to the `Clone` impl which has to fill the dead array elements with something, but cannot fill it with a correct instance.
- Are the unit tests sufficient?
CC #25725
Tweak format string error to point at arguments always
Add secondary span labels with no text to make it clear when there's a
mismatch bewteen the positional arguments in a format string and the
arguments to the macro. This shouldn't affect experienced users, but it
should make it easier for newcomers to more clearly understand how
`format!()` and `println!()` are supposed to be used.
```
error: 2 positional arguments in format string, but there is 1 argument
--> file8.rs:2:14
|
2 | format!("{} {}", 1);
| ^^ ^^ -
```
instead of
```
error: 2 positional arguments in format string, but there is 1 argument
--> file8.rs:2:14
|
2 | format!("{} {}", 1);
| ^^ ^^
```
r? @Centril
Add secondary span labels with no text to make it clear when there's a
mismatch bewteen the positional arguments in a format string and the
arguments to the macro. This shouldn't affect experienced users, but it
should make it easier for newcomers to more clearly understand how
`format!()` and `println!()` are supposed to be used.
```
error: 2 positional arguments in format string, but there is 1 argument
--> file8.rs:2:14
|
2 | format!("{} {}", 1);
| ^^ ^^ -
```
instead of
```
error: 2 positional arguments in format string, but there is 1 argument
--> file8.rs:2:14
|
2 | format!("{} {}", 1);
| ^^ ^^
```
This commit modifies the uninhabitedness checking so that the fields of
a non-exhaustive variant (which is not local) are ignored if they are
uninhabited. This is an improvement over the previous behaviour which
considered all non-local non-exhaustive variants useful because
unreachable patterns are now detected.
Signed-off-by: David Wood <david@davidtw.co>
Derive `Rustc{En,De}codable` for `TokenStream`.
`TokenStream` used to be a complex type, but it is now just a newtype
around a `Lrc<Vec<TreeAndJoint>>`. Currently it uses custom encoding
that discards the `IsJoint` and custom decoding that adds `NonJoint`
back in for every token tree. This requires building intermediate
`Vec<TokenTree>`s.
This commit makes `TokenStream` derive `Rustc{En,De}codable`. This
simplifies the code, and avoids the creation of the intermediate
vectors, saving up to 3% on various benchmarks. It also changes the AST
JSON output in one test.
r? @petrochenkov
Avoid ICE when checking `Destination` of `break` inside a closure
Fix#65383, fix#62480. This is a `[regression-from-stable-to-stable]` and a fairly small change to avoid the ICE by properly handling this case.
Lockless LintStore
This removes mutability from the lint store after registration. Each commit stands alone, for the most part, though they don't make sense out of sequence.
The intent here is to move LintStore to a more parallel-friendly architecture, although also just a cleaner one from an implementation perspective. Specifically, this has the following changes:
* We no longer implicitly register lints when registering lint passes
* For the most part this means that registration calls now likely want to call something like:
`lint_store.register_lints(&Pass::get_lints())` as well as `register_*_pass`.
* In theory this is a simplification as it's much easier for folks to just register lints and then have passes that implement whichever lint however they want, rather than necessarily tying passes to lints.
* Lint passes still have a list of associated lints, but a followup PR could plausibly change that
* This list must be known for a given pass type, not instance, i.e., `fn get_lints()` is the signature instead of `fn get_lints(&self)` as before.
* We do not store pass objects, instead storing constructor functions. This means we always get new passes when running lints (this happens approximately once though for a given compiler session, so no behavior change is expected).
* Registration API is _much_ simpler: generally all functions are just taking `Fn() -> PassObject` rather than several different `bool`s.
Add some tests for fixed ICEs
Fixes#41366 from 1.35.0
Fixes#51431 from 1.31.0-nightly (77af31408 2018-10-11) (on my local)
Fixes#52437 from nightly
Fixes#63496 from nightly
r? @Centril
Fix test style in unused parentheses lint test
I think this fixes#63237
I'm not sure if I had to add text after the `//~ ERROR` comments.
This is my first pull request, so I'm open to feedback.
This issues already received one pull request [here](https://github.com/rust-lang/rust/pull/63257) but it was marked as closed for inactivity.
r? @nikomatsakis
Add more coherence tests
I've wrote the missing test cases listed in [this google doc](https://docs.google.com/spreadsheets/d/1WlroTEXE6qxxGvEOhICkUpqguYZP9YOZEvnmEtSNtM0/edit#gid=0)
> The other thing that might be useful is to rename the existing tests so they all fit the new naming scheme we were using.
I'm not entirely sure how to do this. If everything from the google sheet is covered could I just remove the remaining tests in `src/test/ui/coherence` or is there something in there that should remain?
cc #63599
r? @nikomatsakis
