This commit fixes a false positive of the warning triggered for #138762
and the fix is to codify that zero-sized types are "safe" in both the
old and new ABIs.
(cherry picked from commit f9091e24a0)
Do not treat lifetimes from parent items as influencing child items
```rust
struct A;
impl Bar<'static> for A {
const STATIC: &str = "";
// ^ no future incompat warning
}
```
has no future incompat warning, because there is no ambiguity. But
```rust
struct C;
impl Bar<'_> for C {
// ^^ this lifeimte
const STATIC: &'static str = {
struct B;
impl Bar<'static> for B {
const STATIC: &str = "";
// causes ^ to emit a future incompat warning
}
""
};
}
```
had one before this PR, because the impl for `B` (which is just a copy of `A`) thought it was influenced by a lifetime on the impl for `C`.
I double checked all other `lifetime_ribs` iterations and all of them do check for `Item` boundaries. This feels very fragile tho, and ~~I think we should do not even be able to see ribs from parent items, but that's a different refactoring that I'd rather not do at the same time as a bugfix~~. EDIT: ah nevermind, this is needed for improving diagnostics like "use of undeclared lifetime" being "can't use generic parameters from outer item" instead.
r? `@compiler-errors`
Greatly simplify doctest parsing and information extraction
The original process was pretty terrible, as it tried to extract information such as attributes by performing matches over tokens like `#!`, which doesn't work very well considering you can have `# ! [`, which is valid.
Also, it now does it in one pass: if the parser is happy, then we try to extract information, otherwise we return early.
r? `@fmease`
Avoid wrapping constant allocations in packed structs when not necessary
This way LLVM will set the string merging flag if the alloc is a nul terminated string, reducing binary sizes.
try-job: armhf-gnu
Rollup of 6 pull requests
Successful merges:
- #138720 (Specify a concrete stack size in channel tests)
- #139010 (Improve `xcrun` error handling)
- #139021 (std: get rid of pre-Vista fallback code)
- #139025 (Do not trim paths in MIR validator)
- #139026 (Use `abs_diff` where applicable)
- #139030 (saethlin goes on vacation)
r? `@ghost`
`@rustbot` modify labels: rollup
Remove `kw::Empty` uses from `hir::Lifetime::ident`
`hir::Lifetime::ident` is sometimes set to `kw::Empty` and it's really confusing. This PR stops that. Helps with #137978.
r? `@lcnr`
Do not trim paths in MIR validator
From my inline comment:
```
// The type checker formats a bunch of strings with type names in it, but these strings
// are not always going to be encountered on the error path since the inliner also uses
// the validator, and there are certain kinds of inlining (even for valid code) that
// can cause validation errors (mostly around where clauses and rigid projections).
```
Fixes https://github.com/rust-lang/rust/issues/138979
r? `@jieyouxu`
Specify a concrete stack size in channel tests
The channel-stack-overflow-issue-102246 regression test fails on platforms with a small default stack size (e.g. Fuchsia, with a default of 256KiB). Update the test to specify an exact stack size for both the sender and receiver operations, to ensure it is platform agnostic.
Set the stack size to less than the total allocation size of the mpsc channel, to continue to prove that the allocation is on the heap.
`hir::Lifetime::ident` currently sometimes uses `kw::Empty` for elided
lifetimes and sometimes uses `kw::UnderscoreLifetime`, and the
distinction is used when creating some error suggestions, e.g. in
`Lifetime::suggestion` and `ImplicitLifetimeFinder::visit_ty`. I found
this *really* confusing, and it took me a while to understand what was
going on.
This commit replaces all uses of `kw::Empty` in `hir::Lifetime::ident`
with `kw::UnderscoreLifetime`. It adds a new field
`hir::Lifetime::is_path_anon` that mostly replaces the old
empty/underscore distinction and makes things much clearer.
Some other notable changes:
- Adds a big comment to `Lifetime` talking about permissable field
values.
- Adds some assertions in `new_named_lifetime` about what ident values
are permissible for the different `LifetimeRes` values.
- Adds a `Lifetime::new` constructor that does some checking to make
sure the `is_elided` and `is_anonymous` states are valid.
- `add_static_impl_trait_suggestion` now looks at `Lifetime::res`
instead of the ident when creating the suggestion. This is the one
case where `is_path_anon` doesn't replace the old empty/underscore
distinction.
- A couple of minor pretty-printing improvements.
HIR printing currently gets very little testing. This increases coverage
a bit, with a focus on lifetimes.
There are some FIXME comments for cases that are printed in a dubious
fashion. This PR won't address those; the point of adding this test is
to ensure that the subsequent commits don't hurt pretty-printing.
Improve suggest construct with literal syntax instead of calling
Closing #138931
When constructing a structure through a format similar to calling a constructor, we can use verbose suggestions to hint at using literal syntax for clearer advice. The case of multiple fields is also considered here, provided that the field has the same number of arguments as CallExpr.
r? compiler
expand: Leave traces when expanding `cfg` attributes
This is the same as https://github.com/rust-lang/rust/pull/138515, but for `cfg(true)` instead of `cfg_attr`.
The difference is that `cfg(true)`s already left "traces" after themselves - the `cfg` attributes themselves, with `expanded_inert_attrs` set to true, with full tokens, available to proc macros.
This is not a reasonably expected behavior, but it could not be removed without a replacement, because a [major rustdoc feature](https://github.com/rust-lang/rfcs/pull/3631) and a number of clippy lints rely on it. This PR implements a replacement.
This needs a crater run, because it changes observable behavior (in an intended way) - proc macros can no longer see expanded `cfg(true)` attributes.
(Some minor unnecessary special casing for `sym::cfg_attr` is also removed in this PR.)
r? `@nnethercote`
Use the correct binder scope for elided lifetimes in assoc consts
Beyond diagnostics this has no real effect, and it's also just about a future incompat lint. But it causes ICEs in some refactorings that I'm doing, so trying to get it out of the way
Collect items referenced from var_debug_info
The collection is limited to full debuginfo builds to match behavior of FunctionCx::compute_per_local_var_debug_info.
Fixes#138942.
Implement lint against using Interner and InferCtxtLike in random compiler crates
Often `Interner` defines similar methods to `TyCtxt` (but often simplified due to the simpler API surface of the type system layer for the new solver), which people will either unintentionally or intentionally import and use. Let's discourage that.
r? lcnr
Add environment variable query
Generally, `rustc` prefers command-line arguments, but in some cases, an environment variable really is the most sensible option. We should make sure that this works properly with the compiler's change-tracking mechanisms, such that changing the relevant environment variable causes a rebuild.
This PR is a first step forwards in doing that.
Part of the work needed to do https://github.com/rust-lang/rust/issues/118204, see https://github.com/rust-lang/rust/pull/129342 for some discussion.
r? ``@petrochenkov``
This currently works because it's part of expansion, and that isn't yet
tracked by the query system. But we want to ensure it continues working,
even if that is changed.
