Changes from #88558 allowed using `~const Drop` in constants by
introducing a new `NeedsNonConstDrop` qualif.
The new qualif was also used for promotion purposes, and allowed
promotion to happen for values that needs to be dropped but which
do have a const drop impl.
Since for promoted the drop implementation is never executed,
this lead to observable change in behaviour. For example:
```rust
struct Panic();
impl const Drop for Panic {
fn drop(&mut self) {
panic!();
}
}
fn main() {
let _ = &Panic();
}
```
Restore the use of `NeedsDrop` qualif during promotion to avoid the issue.
Nicer error message if the user attempts to do let...else if
Gives a nice "conditional `else if` is not supported for `let...else`" error when encountering a `let...else if` pattern, as suggested in the [let...else tracking issue](https://github.com/rust-lang/rust/issues/87335#issuecomment-944846205).
Some "parenthesis" and "parentheses" fixes
"Parenthesis" is the singular (e.g. one `(` or one `)`) and "parentheses" is the plural (multiple `(` or `)`s) and this is not hard to mix up so here are some fixes for that.
Inspired by #89958
ty::pretty: prevent infinite recursion for `extern crate` paths.
Fixes#55779, fixes#87932.
This fix is based on `@estebank's` idea in https://github.com/rust-lang/rust/issues/55779#issuecomment-614758510 - but instead of trying to get `try_print_visible_def_path_recur`'s cycle detection to work in this case, this PR "just" disables the "visible path" feature when printing the path to an `extern crate`, so that the old recursion chain of `try_print_visible_def_path -> print_def_path -> try_print_visible_def_path`, is now impossible.
Both tests have been confirmed to crash `rustc` because of a stack overflow, without the fix.
polymorphization: shims and predicates
Supersedes #75737 and #75414. This pull request includes up some changes to polymorphization which hadn't landed previously and gets stage2 bootstrapping and the test suite passing when polymorphization is enabled. There are still issues with `type_id` and polymorphization to investigate but this should get polymorphization in a reasonable state to work on.
- #75737 and #75414 both worked but were blocked on having the rest of the test suite pass (with polymorphization enabled) with and without the PRs. It makes more sense to just land these so that the changes are in.
- #75737's changes remove the restriction of `InstanceDef::Item` on polymorphization, so that shims can now be polymorphized. This won't have much of an effect until polymorphization's analysis is more advanced, but it doesn't hurt.
- #75414's changes remove all logic which marks parameters as used based on their presence in predicates - given #75675, this will enable more polymorphization and avoid the symbol clashes that predicate logic previously sidestepped.
- Polymorphization now explicitly checks (and skips) foreign items, this is necessary for stage2 bootstrapping to work when polymorphization is enabled.
- The conditional determining the emission of a note adding context to a post-monomorphization error has been modified. Polymorphization results in `optimized_mir` running for shims during collection where that wouldn't happen previously, some errors are emitted during `optimized_mir` and these were considered post-monomorphization errors with the existing logic (more errors and shims have a `DefId` coming from the std crate, not the local crate), adding a note that resulted in tests failing. It isn't particularly feasible to change where polymorphization runs or prevent it from using `optimized_mir`, so it seemed more reasonable to not change the conditional.
- `characteristic_def_id_of_type` was being invoked during partitioning for self types of impl blocks which had projections that depended on the value of unused generic parameters of a function - this caused a ICE in a debuginfo test. If partitioning is enabled and the instance needs substitution then this is skipped. That test still fails for me locally, but not with an ICE, but it fails in a fresh checkout too, so 🤷♂️.
r? `@lcnr`
Remove FIXME since there is nothing to be fixed
Resolves#88593.
The errors are deduplicated when displayed to users. They only appear
multiple times in UI tests.
cc ``@jyn514``
r? ``@camelid``
Remove trailing semicolon from macro call span
Macro call site spans are now less surprising/more consistent since they no longer contain a semicolon after the macro call.
The downside is that we need to do a little guesswork to get the semicolon in diagnostics. But this should not be noticeable since it is rare for the semicolon to not immediately follow the macro call.
emitter: current substitution can be multi-line
Fixes#89280.
In `splice_lines`, there is some arithmetic to compute the required alignment such that future substitutions in a suggestion are aligned correctly. However, this assumed that the current substitution's span was only on a single line. In circumstances where this was not true, it could result in a arithmetic overflow when the substitution's end column was less than the substitution's start column.
r? ````@oli-obk````
Restrict the aarch64 outline atomics test to Linux
The test was introduced in #83655, which enables the `outline-atomics` feature for aarch64-unknown-linux-* but not for any other aarch64 targets. The test did not check for Linux causing test failures on aarch64-apple-darwin.
r? `@workingjubilee`
Stabilize `unreachable_unchecked` as `const fn`
Closes#53188
This PR stabilizes `core::hint::unreachable_unchecked` as `const fn`. MIRI is able to detect when this method is called. Stabilization was delayed until `const_panic` was stabilized so as to avoid users calling this method in its place (thus resulting in runtime UB). With #89508, that is no longer an issue.
````@rustbot```` label +A-const-eval +A-const-fn +T-lang +S-blocked
(not sure why it's T-lang, but that's what the tracking issue is)
Use BCryptGenRandom instead of RtlGenRandom on Windows.
This removes usage of RtlGenRandom on Windows, in favour of BCryptGenRandom.
BCryptGenRandom isn't available on XP, but we dropped XP support a while ago.
In `splice_lines`, there is some arithmetic to compute the required
alignment such that future substitutions in a suggestion are aligned
correctly. However, this assumed that the current substitution's span
was only on a single line. In circumstances where this was not true, it
could result in a arithmetic overflow when the substitution's end
column was less than the substitution's start column.
Signed-off-by: David Wood <david.wood@huawei.com>
Rollup of 7 pull requests
Successful merges:
- #86011 (move implicit `Sized` predicate to end of list)
- #89821 (Add a strange test for `unsafe_code` lint.)
- #89859 (add dedicated error variant for writing the discriminant of an uninhabited enum variant)
- #89870 (Suggest Box::pin when Pin::new is used instead)
- #89880 (Use non-checking TLS relocation in aarch64 asm! sym test.)
- #89885 (add long explanation for E0183)
- #89894 (Remove unused dependencies from rustc_const_eval)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Use non-checking TLS relocation in aarch64 asm! sym test.
The checking variant ensures that the offset required is not larger than 12 bits - hence we wouldn't ever need the upper 12 bits.
It's unlikely to ever fail in this small test but this is technically correct.
This was noticed incidentally when we found that LLD doesn't support the `tprel_lo12` relocation, even though LLVM can apparently generate it when using `-mtls-size=12`.
Suggest Box::pin when Pin::new is used instead
This fixes an incorrect diagnostic.
**Based on #89390**; only the last commit is specific to this PR. "Ignore whitespace changes" also helps here.
Add a strange test for `unsafe_code` lint.
The current behavior is a little surprising to me. I'm not sure whether people would change it, but at least let me document the current behavior with a test.
I learnt about this from the [totally-speedy-transmute](https://docs.rs/totally-speedy-transmute) crate.
cc #10599 the original implementation pr.
move implicit `Sized` predicate to end of list
In `Bounds::predicates()`, move the implicit `Sized` predicate to the
end of the generated list. This means that if there is an explicit
`Sized` bound, it will be checked first, and any resulting
diagnostics will have a more useful span.
Fixes#85998, at least partially. ~~Based on #85979, but only the last 2 commits are new for this pull request.~~ (edit: rebased) A full fix would need to deal with where-clauses, and that seems difficult. Basically, predicates are being collected in multiple stages, and there are two places where implicit `Sized` predicates can be inserted: once for generic parameters, and once for where-clauses. I think this insertion is happening too early, and we should actually do it only at points where we collect all of the relevant trait bounds for a type parameter.
I could use some help interpreting the changes to the stderr output. It looks like reordering the predicates changed some diagnostics that don't obviously have anything to do with `Sized` bounds. Possibly some error reporting code is making assumptions about ordering of predicates? The diagnostics for src/test/ui/derives/derives-span-Hash-*.rs seem to have improved, no longer pointing at the type parameter identifier, but src/test/ui/type-alias-impl-trait/generic_duplicate_param_use9.rs became less verbose for some reason.
I also ran into an instance of #84970 while working on this, but I kind of expected that could happen, because I'm reordering predicates. I can open a separate issue on that if it would be helpful.
``@estebank`` this seems likely to conflict (slightly?) with your work on #85947; how would you like to resolve that?
Fix incorrect Box::pin suggestion
The suggestion checked if `Pin<Box<T>>` could be coeerced to the expected
type, but did not check predicates created by the coercion. We now
look for predicates that definitely cannot be satisfied before giving
the suggestion.
The suggestion is still marked MaybeIncorrect because we allow predicates that
are still ambiguous and can't be proven.
Fixes#72117.
Add check that live_region is live in sanitize_promoted
This pull request fixes#88434 by adding a check in `sanitize_promoted` to ensure that only regions which are actually live are added to the `liveness_constraints` of the `BorrowCheckContext`.
To implement this change, I needed to add a method to `LivenessValues` which gets the elements contained by a region:
/// Returns an iterator of all the elements contained by the region `r`
crate fn get_elements(&self, row: N) -> impl Iterator<Item = Location> + '_
Then, inside `sanitize_promoted`, we check whether the iterator returned by this method is non-empty to ensure that the region is actually live at at least one location before adding that region to the `liveness_constraints` of the `BorrowCheckContext`.
This is my first pull request to the Rust repo, so any feedback on how I can improve this pull request or if there is a better way to fix this issue would be very appreciated.
Add `const_eval_select` intrinsic
Adds an intrinsic that calls a given function when evaluated at compiler time, but generates a call to another function when called at runtime.
See https://github.com/rust-lang/const-eval/issues/7 for previous discussion.
r? `@oli-obk.`
