Allow using generic trait methods in `const fn`
Next step for https://github.com/rust-lang/rust/issues/67792, this now also allows code like the following:
```rust
struct S;
impl const PartialEq for S {
fn eq(&self, _: &S) -> bool {
true
}
}
const fn equals_self<T: PartialEq>(t: &T) -> bool {
*t == *t
}
pub const EQ: bool = equals_self(&S);
```
This works by threading const-ness of trait predicates through trait selection, in particular through `ParamCandidate`, and exposing it in the resulting `ImplSource`.
Since this change makes two bounds `T: Trait` and `T: ?const Trait` that only differ in their const-ness be treated like different bounds, candidate winnowing has been changed to drop the `?const` candidate in favor of the const candidate, to avoid ambiguities when both a const and a non-const bound is present.
const_generics: assert resolve hack causes an error
prevent the min_const_generics `HACK`s in resolve from triggering a fallback path which successfully compiles so that we don't have to worry about future compat issues when removing it
r? `@eddyb` cc `@varkor`
Consolidate exhaustiveness-related tests
I hunted for tests that only exercised the match exhaustiveness algorithm and regrouped them. I also improved integer-range tests since I had found them lacking while hacking around.
The interest is mainly so that one can pass `--test-args patterns` and catch most relevant tests.
r? `@varkor`
`@rustbot` modify labels: +A-exhaustiveness-checking
More consistently use spaces after commas in lists in docs
This PR changes instances of lists that didn't use spaces after commas, like `vec![1,2,3]`, to `vec![1, 2, 3]` to be more consistent with idiomatic Rust style (the way these were looks strange to me, especially because there are often lists that *do* use spaces after the commas later in the same code block 😬).
I noticed one of these in an example in the stdlib docs and went looking for more, but as far as I can see, I'm only changing those spots in user-facing documentation or rustc output, and the changes make no semantic difference.
Direct RUSTC_LOG (tracing/log) output to stderr instead of stdout.
Looks like this got missed in the initial implementation, AFAIK the old behavior was to output on stderr.
(Hit this while trying to debug `rustc` running inside a build script which was only letting stderr through)
r? ``@oli-obk`` cc ``@davidbarsky`` ``@hawkw``
Fix links to extern types in rustdoc (fixes#78777)
r? `@jyn514`
Fixes#78777.
The initial fix we tried was:
```diff
diff --git a/src/librustdoc/passes/collect_intra_doc_links.rs b/src/librustdoc/passes/collect_intra_doc_links.rs
index 8be9482acff..c4b7086fdb1 100644
--- a/src/librustdoc/passes/collect_intra_doc_links.rs
+++ b/src/librustdoc/passes/collect_intra_doc_links.rs
`@@` -433,8 +433,9 `@@` impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
Res::PrimTy(prim) => Some(
self.resolve_primitive_associated_item(prim, ns, module_id, item_name, item_str),
),
- Res::Def(DefKind::Struct | DefKind::Union | DefKind::Enum | DefKind::TyAlias, did) => {
+ Res::Def(kind, did) if kind.ns() == Some(Namespace::TypeNS) => {
debug!("looking for associated item named {} for item {:?}", item_name, did);
+
// Checks if item_name belongs to `impl SomeItem`
let assoc_item = cx
.tcx
```
However, this caused traits to be matched, resulting in a panic when `resolve_associated_trait_item` is called further down in this function.
This PR also adds an error message for that panic. Currently it will look something like:
```rust
thread 'rustc' panicked at 'Not a type: DefIndex(8624)', compiler/rustc_metadata/src/rmeta/decoder.rs:951:32
```
I wasn't sure how to get a better debug output than `DefIndex(...)`, and am open to suggestions.
It is applied exactly when the return value has an indirect pass mode.
Except for InReg on x86 fastcall, arg attrs are now only used for
optimization purposes and thus are fine to ignore.
lint: Do not provide suggestions for non standard characters
Fixes#77273
Only provide suggestions if the case-fixed result is different than the original.
rustc_expand: Mark inner `#![test]` attributes as soft-unstable
Custom inner attributes are feature gated (https://github.com/rust-lang/rust/issues/54726) except for attributes having name `test` literally, which are not gated for historical reasons.
`#![test]` is an inner proc macro attribute, so it has all the issues described in https://github.com/rust-lang/rust/issues/54726 too.
This PR gates it with the `soft_unstable` lint.
Reworks Sccc computation to iteration instead of recursion
Linear graphs, producing as many scc's as nodes, would recurse once for every node when entered from the start of the list. This adds a test that exhausted the stack at least on my machine with error:
```
thread 'graph::scc::tests::test_deep_linear' has overflowed its stack
fatal runtime error: stack overflow
```
This may or may not be connected to #78567. I was only reminded that I started this rework some time ago. It might be plausible as borrow checking a long function with many borrow regions around each other—((((((…))))))— may produce the linear list setup to trigger this stack overflow ? I don't know enough about borrow check to say for sure.
This is best read in two separate commits. The first addresses only `find_state` internally. This is classical union phase from union-find. There's also a common solution of using the parent pointers in the (virtual) linked list to track the backreferences while traversing upwards and then following them backwards in a second path compression phase.
The second is more involved as it rewrites the mutually recursive `walk_node` and `walk_unvisited_node`. Firstly, the caller is required to handle the unvisited case of `walk_node` so a new `start_walk_from` method is added to handle that by walking the unvisited node if necessary. Then `walk_unvisited_node`, where we would previously recurse into in the missing case, is rewritten to construct a manual stack of its frames. The state fields consist of the previous stack slots.
Arena: use specialization to avoid copying data
In several cases, a `Vec` or `SmallVec` is passed to `Arena::alloc_from_iter` directly. This PR makes sure those cases don't copy their data unnecessarily, by specializing the `alloc_from_iter` implementation.
Never inline naked functions
The `#[naked]` attribute disabled prologue / epilogue emission for the
function and it is responsibility of a developer to provide them. The
compiler is no position to inline such functions correctly.
Disable inlining of naked functions at LLVM and MIR level.
Closes#60919.
Add lint for panic!("{}")
This adds a lint that warns about `panic!("{}")`.
`panic!(msg)` invocations with a single argument use their argument as panic payload literally, without using it as a format string. The same holds for `assert!(expr, msg)`.
This lints checks if `msg` is a string literal (after expansion), and warns in case it contained braces. It suggests to insert `"{}", ` to use the message literally, or to add arguments to use it as a format string.
This lint is also a good starting point for adding warnings about `panic!(not_a_string)` later, once [`panic_any()`](https://github.com/rust-lang/rust/pull/74622) becomes a stable alternative.
The `#[naked]` attribute disabled prologue / epilogue emission for the
function and it is responsibility of a developer to provide them. The
compiler is no position to inline such functions correctly.
Disable inlining of naked functions at LLVM and MIR level.
