remove outdated coherence hack
we have a more precise detection for downstream conflicts in candidate assembly: the `is_knowable` check in `candidate_from_obligation_no_cache`.
r? types cc `@nikomatsakis`
Fix perf regression from TypeVisitor changes
Regression occurred in https://github.com/rust-lang/rust/pull/101858#issuecomment-1248732579
Instead of just reverting, we only fixed part of the regression. The main regression was due to actually correctly visiting a type that contains types and consts and should therefor be visited. This is not actually observable (yet?), but we should still do it correctly instead of risking major bugs in the future.
fix: infer for-loop item type with `IntoIterator` and `Iterator`
Part of #13299
We've been inferring the type of the yielded values in for-loop as `<T as IntoIterator>::Item`. We infer the correct type most of the time when we normalize the projection type, but it turns out not always. We should infer the type as `<<T as IntoIterator>::IntoIter as Iterator>::Item`.
When one specifies `IntoIter` assoc type of `IntoIterator` but not `Item` in generic bounds, we fail to normalize `<T as IntoIterator>::Item` (even though `IntoIter` is defined like so: `type IntoIter: Iterator<Item = Self::Item>` - rustc does *not* normalize projections based on other projection's bound I believe; see [this playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=e88e19385094cb98fadbf647b4c2082e)).
Note that this doesn't fully fix # 13299 - given the following code, chalk can normalize `<I as IntoIterator>::IntoIter` to `S`, but cannot normalize `<S as Iterator>::Item` to `i32`.
```rust
struct S;
impl Iterator for S { type Item = i32; /* ... */ }
fn f<I: IntoIterator<IntoIter = S>>(it: I) {
for elem in it {}
//^^^^{unknown}
}
```
This is because chalk finds multiple answers that satisfy the query `AliasEq(<S as Iterator>::Item = ?X`: `?X = i32` and `?X = <I as IntoIterator>::Item` - which are supposed to be the same type due to the aforementioned bound on `IntoIter` but chalk is unable to figure it out.
Enable inline stack probes on PowerPC and SystemZ
The LLVM PowerPC and SystemZ targets have both supported `"probe-stack"="inline-asm"` for longer than our current minimum LLVM 13 requirement, so we can turn this on for all `powerpc`, `powerpc64`, `powerpc64le`, and `s390x` targets in Rust. These are all tier-2 or lower, so CI does not run their tests, but I have confirmed that their `linux-gnu` variants do pass on RHEL.
cc #43241
Make the `c` feature for `compiler-builtins` an explicit opt-in
Its build script doesn't support cross-compilation. I tried fixing it, but the cc crate itself doesn't appear to support cross-compiling to windows either unless you use the -gnu toolchain:
```
error occurred: Failed to find tool. Is `lib.exe` installed?
```
Fixes https://github.com/rust-lang/rust/issues/101172.
Rewrite and refactor format_args!() builtin macro.
This is a near complete rewrite of `compiler/rustc_builtin_macros/src/format.rs`.
This gets rid of the massive unmaintanable [`Context` struct](76531befc4/compiler/rustc_builtin_macros/src/format.rs (L176-L263)), and splits the macro expansion into three parts:
1. First, `parse_args` will parse the `(literal, arg, arg, name=arg, name=arg)` syntax, but doesn't parse the template (the literal) itself.
2. Second, `make_format_args` will parse the template, the format options, resolve argument references, produce diagnostics, and turn the whole thing into a `FormatArgs` structure.
3. Finally, `expand_parsed_format_args` will turn that `FormatArgs` structure into the expression that the macro expands to.
In other words, the `format_args` builtin macro used to be a hard-to-maintain 'single pass compiler', which I've split into a three phase compiler with a parser/tokenizer (step 1), semantic analysis (step 2), and backend (step 3). (It's compilers all the way down. ^^)
This can serve as a great starting point for https://github.com/rust-lang/rust/issues/99012, which will only need to change the implementation of 3, while leaving step 1 and 2 unchanged.
It also makes https://github.com/rust-lang/compiler-team/issues/541 easier, which could then upgrade the new `FormatArgs` struct to an `ast` node and remove step 3, moving that step to later in the compilation process.
It also fixes a few diagnostics bugs.
This also [significantly reduces](https://gist.github.com/m-ou-se/b67b2d54172c4837a5ab1b26fa3e5284) the amount of generated code for cases with arguments in non-default order without formatting options, like `"{1} {0}"` or `"{a} {}"`, etc.
Amalgamate file changes for the same file ids in process_changes
When receiving multiple change events for a single file id where the last change is a delete the server panics, as it tries to access the file contents of a deleted file. This occurs due to the VFS changes and the in memory file contents being updated immediately, while `process_changes` processes the events afterwards in sequence which no longer works as it will only observe the final file contents. By folding these events together, we will no longer try to process these intermediate changes, as they aren't relevant anyways.
Potentially fixes https://github.com/rust-lang/rust-analyzer/issues/13236
When receiving multiple change events for a single file id where the
last change is a delete the server panics, as it tries to access the
file contents of a deleted file. This occurs due to the VFS changes and
the in memory file contents being updated immediately, while
`process_changes` processes the events afterwards in sequence which no
longer works as it will only observe the final file contents. By
folding these events together, we will no longer try to process these
intermediate changes, as they aren't relevant anyways.
Potentially fixes https://github.com/rust-lang/rust-analyzer/issues/13236
Feature: Add assist to unwrap tuple declarations
> Implement #12923 for only tuples.
>
> Does not implement unwrapping for structs, as mentioned in the issue.
Add assist to unwrap tuples declarations to separate declarations.
```rust
fn main() {
$0let (foo, bar, baz) = (1.0, "example", String::new())
}
```
becomes:
```rust
fn main() {
let foo = 1.0;
let bar = "example";
let baz = String::new();
}
```
## Changelog
### Feature
- Added assist to unwrap tuple declarations.
feat: type inference for generators
This PR implements basic type inference for generator and yield expressions.
Things not included in this PR:
- Generator upvars and generator witnesses are not implemented. They are only used to determine auto trait impls, so basic type inference should be fine without them, but method resolutions with auto trait bounds may not be resolved correctly.
Open questions:
- I haven't (yet) implemented `HirDisplay` for `TyKind::Generator`, so generator types are just shown as "{{generator}}" (in tests, inlay hints, hovers, etc.), which is not really nice. How should we show them?
- I added moderate amount of stuffs to minicore. I especially didn't want to add `impl<T> Deref for &T` and `impl<T> Deref for &mut T` exclusively for tests for generators; should I move them into the test fixtures or can they be placed in minicore?
cc #4309
Don't drop parent substs when we have no generic parameters in `create_substs_for_ast_path`
This bug is being shadowed by an explicit check for `generics.params.is_empty()` in the only parent caller that could trigger it (`create_substs_for_associated_item`). I triggered it on another branch where I'm messing around with astconv stuff.
Also, the second commit simplifies `create_substs_for_associated_item`. Removing that explicit check I mentioned above^ and also the special case call to `Astconv::prohibit_generics` causes the UI test `src/test/ui/structs/struct-path-associated-type.stderr` to change, but I think that it's clearer now. The suggestion to remove the generics is actually useful.
