We now make `'empty` indexed by a universe index, resulting
in a region lattice like this:
```
static ----------+-----...------+ (greatest)
| | |
early-bound and | |
free regions | |
| | |
scope regions | |
| | |
empty(root) placeholder(U1) |
| / |
| / placeholder(Un)
empty(U1) -- /
| /
... /
| /
empty(Un) -------- (smallest)
```
Therefore, `exists<A> { forall<B> { B: A } }` is now unprovable,
because A must be at least Empty(U1) and B is placeholder(U2), and hence
the two regions are unrelated.
We currently have a kind of arbitrary check for `Verify` conditions
which says that if the "test region" is `'empty`, then the check
passes. This was added to fix#42467 -- it happens to be correct for
the purposes that we use verify bounds for, but it doesn't feel
generally correct. Replace with a more principled test.
In the docs for option.rs and result.rs, it is noted for all *_or()
functions that they are eagerly evaluated, except for the map_or()
function.
This commit adds this missing documentation to the two files.
stop using BytePos for computing spans in librustc_parse/parser/mod.rs
Computing spans using logic such as `self.token.span.lo() + BytePos(1)` can cause internal compiler errors like #68730 when non-ascii characters are given as input.
#68735 partially addressed this problem, but only for one case. Moreover, its usage of `next_point()` does not actually align with what `bump_with()` expects. For example, given the token `>>=`, we should pass the span consisting of the final two characters `>=`, but `next_point()` advances the span beyond the end of the `=`.
This pull request instead computes the start of the new span by doing `start_point(self.token.span).hi()`. This matches `self.token.span.lo() + BytePos(1)` in the common case where the characters are ascii, and it gracefully handles multibyte characters.
Fixes#68783.
Make associated item collection a query
Before this change, every time associated items were iterated over (which rustc does *a lot* – this can probably be further optimized), there would be N+1 queries to fetch all assoc. items. Now there's just one after they've been computed once.
Towards unified `fn` grammar
Part of https://github.com/rust-lang/rust/pull/68728.
- Syntactically, `fn` items in `extern { ... }` blocks can now have bodies (`fn foo() { ... }` as opposed to `fn foo();`). As above, we use semantic restrictions instead.
- Syntactically, `fn` items in free contexts (directly in a file or a module) can now be without bodies (`fn foo();` as opposed to `fn foo() { ... }`. As above, we use semantic restrictions instead, including for non-ident parameter patterns.
- We move towards unifying the `fn` front matter; this is fully realized in https://github.com/rust-lang/rust/pull/68728.
r? @petrochenkov
Remove `RefCell` usage from `ObligationForest`.
It's not needed.
This doesn't affect performance, it just simplifies the code a little.
r? @nikomatsakis
rustdoc: attempt full build for compile_fail test
Some code fails when doing a full build but does not fail when only emitting metadata. This commit makes sure compile_fail tests for such code behave as expected, that is, the test succeeds because the compilation fails.
Fixes#67771.
Account for HR lifetimes when suggesting introduction of named lifetime
```
error[E0106]: missing lifetime specifier
--> src/test/ui/suggestions/fn-missing-lifetime-in-item.rs:2:32
|
2 | struct S2<F: Fn(&i32, &i32) -> &i32>(F);
| ---- ---- ^ expected named lifetime parameter
|
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
= note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider making the bound lifetime-generic with a new `'a` lifetime
|
2 | struct S2<F: for<'a> Fn(&'a i32, &'a i32) -> &'a i32>(F);
| ^^^^^^^ ^^^^^^^ ^^^^^^^ ^^^
help: consider introducing a named lifetime parameter
|
2 | struct S2<'a, F: Fn(&'a i32, &'a i32) -> &'a i32>(F);=
| ^^^ ^^^^^^^ ^^^^^^^ ^^^
```
Follow up to #68267. Addresses the diagnostics part of #49287.
Move datatypes definitions in specific modules inside rustc::{traits, infer}
Prelude to #67953
Some data types inside `rustc::traits` and `rustc::infer` are used in other parts of `librustc`. These cannot go to a separate crate `librustc_infer`.
This PR moves those data types to `traits::types` and `infer::types` modules, from where everything is reexported.
Note for review: some imports feature the `crate -> rustc` substitution. This is cruft from the splitting out of #67953. This can be reverted, but are bound to be put back by #67953.
r? @Centril
cc @Zoxc
windows-gnu: prefer system crt libraries if they are available
The origin of the issue is the fact Rust ships mingw-w64 libraries but no headers and prefers own libraries over the system ones.
This leads to situation when headers aren't compatible with libraries (mingw-w64 doesn't provide any forward compatibility and AFAIK backwards compatibility is guaranteed only within major release series).
It's easier to understand how this PR works when looking at the linker invocation before and with this PR: https://www.diffchecker.com/GEuYFmzo
It adds system libraries path before Rust libraries so the linker will prefer them.
It has potential issue when system has files with the same names as Rust but that could be avoided by moving Rust shipped mingw-w64 libraries from `lib/rustlib/x86_64-pc-windows-gnu/lib` to say `lib/rustlib/x86_64-pc-windows-gnu/lib/mingw`. Then adding linker paths in this order: Rust libraries, system libraries, Rust shipped mingw-w64 libraries.
Fixes#47048Fixes#49078Fixes#53454Fixes#60912
