Peephole optimize `x == false` and `x != true`
This adds peephole optimizations to make `x == false`, `false == x`, `x != true`, and `true != x` get optimized to `!x` in the `instcombine` MIR pass. That pass currently handles `x == true` -> `x` already.
Include macro name in 'local ambiguity' error
Currently, we only point at the span of the macro argument. When the
macro call is itself generated by another macro, this can make it
difficult or impossible to determine which macro is responsible for
producing the error.
Enable rustdoc to document safe wasm intrinsics
This commit fixes an issue not found during #84988 where rustdoc is used
to document cross-platform intrinsics but it was requiring that
functions which use `#[target_feature]` are `unsafe` erroneously, even
if they're WebAssembly specific. Rustdoc today, for example, already has
a special case where it enables annotations like
`#[target_feature(enable = "simd128")]` on platforms other than
WebAssembly. The purpose of this commit is to relax the "require all
`#[target_feature]` functions are `unsafe`" requirement for all targets
whenever rustdoc is running, enabling all targets to fully document
other targets, such as WebAssembly, where intrinsics functions aren't
always `unsafe`.
Comment out unused error codes and add description for E0316
I have added an extended description of `E0316` and commented out a bunch of unused error codes to make clear the fact that they are no longer in use. You can check for yourself with
```shell
for ec in \
E0314 E0315 E0473 E0474 E0475 E0479 E0480 E0481 \
E0483 E0484 E0485 E0486 E0487 E0488 E0489
do
if [ ! -z "`grep -r $ec compiler/* --exclude-dir=rustc_error_codes`" ]
then
echo $ec
false
fi
done
```
i.e. these error codes appear nowhere in the compiler code and thus cannot be emitted.
r? ```@GuillaumeGomez```
Currently, we only point at the span of the macro argument. When the
macro call is itself generated by another macro, this can make it
difficult or impossible to determine which macro is responsible for
producing the error.
This commit fixes an issue not found during #84988 where rustdoc is used
to document cross-platform intrinsics but it was requiring that
functions which use `#[target_feature]` are `unsafe` erroneously, even
if they're WebAssembly specific. Rustdoc today, for example, already has
a special case where it enables annotations like
`#[target_feature(enable = "simd128")]` on platforms other than
WebAssembly. The purpose of this commit is to relax the "require all
`#[target_feature]` functions are `unsafe`" requirement for all targets
whenever rustdoc is running, enabling all targets to fully document
other targets, such as WebAssembly, where intrinsics functions aren't
always `unsafe`.
Remove the install prefix from the rpath set when using -Crpath
It was broken anyway for rustup installs and nobody seems to have noticed.
Fixes https://github.com/rust-lang/rust/issues/82392
Unify duplicate linker_and_flavor methods in rustc_codegen_{cranelift,ssa}.
The two methods were exactly the same so this removes the cranelift copy. This will help make sure both they don't get out of sync.
Fix ICE during type layout when there's a `[type error]`
Fixes#84108.
Based on estebank's [comment], except I used `delay_span_bug` because it
should work in more cases, and I think it expresses its intent more
clearly.
r? `@estebank`
[comment]: https://github.com/rust-lang/rust/issues/84108#issuecomment-818916848
Driver improvements
This PR contains a couple of cleanups for the driver and a few small improvements for the custom codegen backend interface. It also implements `--version` and `-Cpasses=list` support for custom codegen backends.
Fix corrected example in E0759.md
This pull request fixes#86061, which was probably caused by a copy-paste error, where the supposedly corrected code example was also marked with `compile_fail`. Thus, the fact that the "correct" example actually _isn't_ correct was not caught by the doc-tests. This pull request removes the incorrect `compile_fail` annotation and fixes the example.
r? ``@GuillaumeGomez``
Fix two ICEs in the parser
This pull request fixes#84104 and fixes#84148. The latter is caused by an invalid `assert_ne!()` in the parser, which I have simply removed because the error is then caught in another part of the parser.
#84104 is somewhat more subtle and has to do with a suggestion to remove extraneous `<` characters; for instance:
```rust
fn main() {
foo::<Ty<<<i32>();
}
```
currently leads to
```
error: unmatched angle brackets
--> unmatched-langle.rs:2:10
|
2 | foo::<Ty<<<i32>();
| ^^^ help: remove extra angle brackets
```
which is obviously wrong and stems from the fact that the code for issuing the above suggestion does not consider the possibility that there might be other tokens in between the opening angle brackets. In #84104, this has led to a span being generated that ends in the middle of a multi-byte character (because the code issuing the suggestion thought that it was only skipping over `<`, which are single-byte), causing an ICE.
Add variance-related information to lifetime error messages
This PR adds a basic framework for displaying variance-related information in error messages. For example:
```
error: lifetime may not live long enough
--> $DIR/type-check-pointer-comparisons.rs:12:5
|
LL | fn compare_mut<'a, 'b>(x: *mut &'a i32, y: *mut &'b i32) {
| -- -- lifetime `'b` defined here
| |
| lifetime `'a` defined here
LL | x == y;
| ^ requires that `'a` must outlive `'b`
|
= help: consider adding the following bound: `'a: 'b`
= note: requirement occurs because of a mutable pointer to &i32
= note: mutable pointers are invariant over their type parameter
= help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
```
The last three lines are new.
This is accomplished by adding a new struct `VarianceDiagInfo`, and passing it along through the various relation methods. When relating types that change the variance (e.g. `&mut T` or `*mut T`), we pass a more specific `VarianceDiagInfo` storing information about the cause of the variance change. When an error, we use the `VarianceDiagInfo` to add additional information to the error message.
This PR doesn't change any variance-related computation or behavior - only diagnostic messages. Therefore, the implementation is quite incomplete - more detailed error messages can be filled in in subsequent PRs.
Limitations:
* We only attempt to deal with invariance - since it's at the bottom of the 'variance lattice', our variance will never change again after it becomes invariant. Handling contravariance would be trickier, since we can change between contravariance and covariance multiple times (e.g. `fn(fn(&'static u8))`). Since contravariance (AFAIK) is only used for function arguments, we can probably get away without a very fancy message for cases involving contravariance.
* `VarianceDiagInfo` currently only handles mutable pointers/references. However, user-defined types (structs, enums, and unions) have the variance of their type parameters inferred, so it would be good to eventually display information about that. We'll want to try to find a balance between displaying too much and too little information about how the variance was inferred.
* The improved error messages are only displayed when `#![feature(nll)]` / `-Z borrowck=mir` is enabled. If issue https://github.com/rust-lang/rust/issues/58781 is not resolved relatively soon, then we might want to duplicate some of this logic in the 'current' (non-NLL) region/outlives handling code.
