Properly parse impls for the never type `!`
Recover from missing `for` in `impl Trait for Type`
Prohibit inherent default impls and default impls of auto traits
Change wording in more diagnostics to use "auto traits"
Some minor code cleanups in the parser
rustc: Tweak `#[target_feature]` syntax
This is an implementation of the `#[target_feature]` syntax-related changes of
[RFC 2045][rfc]. Notably two changes have been implemented:
* The new syntax is `#[target_feature(enable = "..")]` instead of
`#[target_feature = "+.."]`. The `enable` key is necessary instead of the `+`
to indicate that a feature is being enabled, and a sub-list is used for
possible expansion in the future. Additionally within this syntax the feature
names being enabled are now whitelisted against a known set of target feature
names that we know about.
* The `#[target_feature]` attribute can only be applied to unsafe functions. It
was decided in the RFC that invoking an instruction possibly not defined for
the current processor is undefined behavior, so to enable this feature for now
it requires an `unsafe` intervention.
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/2045-target-feature.md
This is an implementation of the `#[target_feature]` syntax-related changes of
[RFC 2045][rfc]. Notably two changes have been implemented:
* The new syntax is `#[target_feature(enable = "..")]` instead of
`#[target_feature = "+.."]`. The `enable` key is necessary instead of the `+`
to indicate that a feature is being enabled, and a sub-list is used for
possible expansion in the future. Additionally within this syntax the feature
names being enabled are now whitelisted against a known set of target feature
names that we know about.
* The `#[target_feature]` attribute can only be applied to unsafe functions. It
was decided in the RFC that invoking an instruction possibly not defined for
the current processor is undefined behavior, so to enable this feature for now
it requires an `unsafe` intervention.
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/2045-target-feature.md
Remove deprecated unstable attribute #[simd]
The `#[simd]` attribute has been deprecated since c8b6d5b23c back in 2015. Any nightly crates using it have had ample time to switch to `#[repr(simd)]`, and if they didn't they're likely broken by now anyway.
r? @eddyb
`struct` pattern parsing and diagnostic tweaks
- Recover from struct parse error on match and point out missing match
body.
- Point at struct when finding non-identifier while parsing its fields.
- Add label to "expected identifier, found {}" error.
Fix#15980.
type error method suggestions use whitelisted identity-like conversions
Previously, on a type mismatch (and if this wasn't preëmpted by a
higher-priority suggestion), we would look for argumentless methods
returning the expected type, and list them in a `help` note. This had two
major shortcomings: firstly, a lot of the suggestions didn't really make
sense (if you used a &str where a String was expected,
`.to_ascii_uppercase()` is probably not the solution you were hoping
for). Secondly, we weren't generating suggestions from the most useful
traits! We address the first problem with an internal
`#[rustc_conversion_suggestion]` attribute meant to mark methods that keep
the "same value" in the relevant sense, just converting the type. We
address the second problem by making `FnCtxt.probe_for_return_type` pass
the `ProbeScope::AllTraits` to `probe_op`: this would seem to be safe
because grep reveals no other callers of `probe_for_return_type`.
Also, structured suggestions are pretty and good for RLS and friends.
Unfortunately, the trait probing is still not all one would hope for: at a
minimum, we don't know how to rule out `into()` in cases where it wouldn't
actually work, and we don't know how to rule in `.to_owned()` where it
would. Issues #46459 and #46460 have been filed and are ref'd in a FIXME.
This is hoped to resolve#42929, #44672, and #45777.
Treat #[path] files as mod.rs files
Fixes https://github.com/rust-lang/rust/issues/46936, cc @briansmith, @SergioBenitez, @nikomatsakis.
This (insta-stable) change treats files included via `#[path = "bla.rs"] mod foo;` as though they were `mod.rs` files. Namely, it allows them to include `mod` statements and looks for the child modules in sibling directories, rather than in relative `modname/childmodule.rs` files as happens for non-`mod.rs` files.
This change makes the `non_modrs_mods` feature backwards compatible with the existing usage in https://github.com/briansmith/ring, several versions of which are currently broken in beta. If we decide to merge, this change should be backported to beta.
cc https://github.com/rust-lang/rust/issues/37872
r? @jseyfried
Add help message for incorrect pattern syntax
When I was getting started with rust I often made the mistake of using `||` instead of `|` to match multiple patterns and spent a long time staring at my code wondering what was wrong.
for example:
```
fn main() {
let x = 1;
match x {
1 || 2 => println!("1 or 2"),
_ => println!("Something else"),
}
}
```
If you compile this with current rustc you will see
```
error: expected one of `...`, `..=`, `..`, `=>`, `if`, or `|`, found `||`
--> test.rs:5:11
|
5 | 1 || 2 => println!("1 or 2"),
| -^^ unexpected token
| |
| expected one of `...`, `..=`, `..`, `=>`, `if`, or `|` here
error: aborting due to previous error
```
With my proposed change it will show:
```
error: unexpected token `||` after pattern
--> test.rs:5:11
|
5 | 1 || 2 => println!("1 or 2"),
| ^^
|
= help: did you mean to use `|` to specify multiple patterns instead?
error: aborting due to previous error
```
- Recover from struct parse error on match and point out missing match
body.
- Point at struct when finding non-identifier while parsing its fields.
- Add label to "expected identifier, found {}" error.
Provide suggestion when trying to use method on numeric literal
New output:
```
error[E0688]: can't call method `powi` on ambiguous numeric type `{float}`
--> $DIR/method-on-ambiguous-numeric-type.rs:12:17
|
12 | let x = 2.0.powi(2);
| ^^^^
help: you must specify a concrete type for this numeric value, like `f32`
|
12 | let x = 2.0_f32.powi(2);
| ^^^^^^^
```
Previous output:
```
error[E0599]: no method named `powi` found for type `{float}` in the current scope
--> src/main.rs:12:17
|
12 | let x = 2.0.powi(2);
| ^^^^
|
= help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope, perhaps add a `use` for it:
|
11 | use core::num::Float;
|
```
Fix#40985.
The `#[simd]` attribute has been deprecated since c8b6d5b23c back in 2015. Any nightly crates using it have had ample time to switch to `#[repr(simd)]`, and if they didn't they're likely broken by now anyway.
Previously, on a type mismatch (and if this wasn't preëmpted by a
higher-priority suggestion), we would look for argumentless methods
returning the expected type, and list them in a `help` note.
This had two major shortcomings. Firstly, a lot of the suggestions didn't
really make sense (if you used a &str where a String was expected,
`.to_ascii_uppercase()` is probably not the solution you were hoping
for). Secondly, we weren't generating suggestions from the most useful
traits!
We address the first problem with an internal
`#[rustc_conversion_suggestion]` attribute meant to mark methods that keep
the "same value" in the relevant sense, just converting the type. We
address the second problem by making `FnCtxt.probe_for_return_type` pass
the `ProbeScope::AllTraits` to `probe_op`: this would seem to be safe
because grep reveals no other callers of `probe_for_return_type`.
Also, structured suggestions are preferred (because they're pretty, but
also for RLS and friends).
Also also, we make the E0055 autoderef recursion limit error use the
one-time-diagnostics set, because we can potentially hit the limit a lot
during probing. (Without this,
test/ui/did_you_mean/recursion_limit_deref.rs would report "aborting due to
51 errors").
Unfortunately, the trait probing is still not all one would hope for: at a
minimum, we don't know how to rule out `into()` in cases where it wouldn't
actually work, and we don't know how to rule in `.to_owned()` where it
would. Issues #46459 and #46460 have been filed and are ref'd in a FIXME.
This is hoped to resolve#42929, #44672, and #45777.
rustc: use {U,I}size instead of {U,I}s shorthands.
`Us`/`Is` come from a time when `us` and `is` were the literal suffixes that are now `usize` / `isize`.
r? @nikomatsakis
Reword reason for move note
On move errors, when encountering an enum variant, be more ambiguous and do not refer to the type on the cause note, to avoid referring to `(maybe as std::prelude::v1::Some).0`, and instead refer to `the value`.
Sidesteps part of the problem with #41962:
```
error[E0382]: use of partially moved value: `maybe`
--> file.rs:5:30
|
5 | if let Some(thing) = maybe {
| ----- ^^^^^ value used here after move
| |
| value moved here
= note: move occurs because the value has type `std::vec::Vec<bool>`, which does not implement the `Copy` trait
error[E0382]: use of moved value: `(maybe as std::prelude::v1::Some).0`
--> file.rs:5:21
|
5 | if let Some(thing) = maybe {
| ^^^^^ value moved here in previous iteration of loop
= note: move occurs because the value has type `std::vec::Vec<bool>`, which does not implement the `Copy` trait
error: aborting due to 2 previous errors
```
Previous discussion: #44360
r? @arielb1
NLL fixes
First, introduce pre-statement effects to dataflow to fix#46875. Edge dataflow effects might make that redundant, but I'm not sure of the best way to integrate them with liveness etc., and if this is a hack, this is one of the cleanest hacks I've seen.
And I want a small fix to avoid the torrent of bug reports.
Second, fix linking of projections to fix#46974
r? @pnkfelix
First cut at getting some part of the test suite working for CloudABI
I am currently working on creating a Docker container for automated CI for CloudABI. Here are some of the trivial changes that need to land to make tests pass.
It looks like many of these tests are already disabled on emscripten,
which also doesn't seem to support environment variables and subprocess
spawning. Just add a similar tag for CloudABI. While there, sort some of
the lists of operating systems alphabetically.
Check all repr hints together when checking for mis-applied attributes
Fixes#47094
Besides fixing that bug, this change has a user-visible effect on the spans in the "incompatible repr hints" warning and another error: they now point at `foo` and/or `bar` in `repr(foo, bar)` instead of the whole attribute. This is sometimes more precise (e.g., `#[repr(C, packed)]` on an enum points at the `packed`) but sometimes not. I moved a compile-fail test to a ui test to illustrate how it now looks in the common case of only one attribute.
