make generalization code create new variables in correct universe
In our type inference system, when we "generalize" a type T to become
a suitable value for a type variable V, we sometimes wind up creating
new inference variables. So, for example, if we are making V be some
subtype of `&'X u32`, then we might instantiate V with `&'Y u32`.
This generalized type is then related `&'Y u32 <: &'X u32`, resulting
in a region constriant `'Y: 'X`. Previously, however, we were making
these fresh variables like `'Y` in the "current universe", but they
should be created in the universe of V. Moreover, we sometimes cheat
in an invariant context and avoid creating fresh variables if we know
the result must be equal -- we can only do that when the universes
work out.
Fixes#57843
r? @pnkfelix
Add specific feature gate error for const-unstable features
Before:
```
error: `impl Trait` in const fn is unstable
--> src/lib.rs:7:19
|
7 | const fn foo() -> impl T {
| ^^^^^^
error: aborting due to previous error
```
After:
```
error[E0723]: `impl Trait` in const fn is unstable (see issue #57563)
--> src/lib.rs:7:19
|
7 | const fn foo() -> impl T {
| ^^^^^^
= help: add #![feature(const_fn)] to the crate attributes to enable
error: aborting due to previous error
```
This improves the situation with https://github.com/rust-lang/rust/issues/57563. Fixes https://github.com/rust-lang/rust/issues/57544. Fixes https://github.com/rust-lang/rust/issues/54469.
r? @oli-obk
In our type inference system, when we "generalize" a type T to become
a suitable value for a type variable V, we sometimes wind up creating
new inference variables. So, for example, if we are making V be some
subtype of `&'X u32`, then we might instantiate V with `&'Y u32`.
This generalized type is then related `&'Y u32 <: &'X u32`, resulting
in a region constriant `'Y: 'X`. Previously, however, we were making
these fresh variables like `'Y` in the "current universe", but they
should be created in the universe of V. Moreover, we sometimes cheat
in an invariant context and avoid creating fresh variables if we know
the result must be equal -- we can only do that when the universes
work out.
rustc_mir: split qualify_consts' "value qualification" bitflags into separate computations.
Prerequisite for computing those bits through a dataflow algorithm ~~(which I might do in this PR later)~~.
This PR should not change behavior overall, other than treating `simd_shuffle*` identically to `#[rustc_args_required_const]` (maybe we should just have `#[rustc_args_required_const]` on the intrinsic imports of `simd_shuffle*`? cc @gnzlbg)
cc @oli-obk @alexreg
Check user type annotations for range patterns.
Fixes#58299.
This PR builds on the fix from #58161 (which fixed miscompilation
caused by the introduction of `AscribeUserType` patterns for associated
constants) to start checking these patterns are well-formed for ranges
(previous fix just ignored them so that miscompilation wouldn't occur).
r? @arielb1
Closure bounds fixes
* Ensures that "nice region errors" are buffered so that they are sorted and migrated correctly.
* Propagates fewer constraints for closures (cc #58178)
* Propagate constraints from closures more precisely (#58127)
Closes#58127
r? @nikomatsakis
Hidden suggestion support
Add way to hide suggestion snippet window from cli output to avoid cluttered spans that don't enhance understanding.
r? @pietroalbini CC @zackmdavis
Tweak "incompatible match arms" error
- Point at the body expression of the match arm with the type error.
- Point at the prior match arms explicitly stating the evaluated type.
- Point at the entire match expr in a secondary span, instead of primary.
- For type errors in the first match arm, the cause is outside of the
match, treat as implicit block error to give a more appropriate error.
Fix#46776, fix#57206.
CC #24157, #38234.
Only suggest imports if not imported.
Fixes#42944 and fixes#53430.
This commit modifies name resolution error reporting so that if a name
is in scope and has been imported then we do not suggest importing it.
This can occur when we add a label about constructors not being visible
due to private fields. In these cases, we know that the struct/variant
has been imported and we should silence any suggestions to import the
struct/variant.
r? @estebank
Improve the error messages for missing stability attributes
This makes the capitalisation consistent and provides more context (especially for missing top-level attributes).
Ignore future deprecations in #[deprecated]
The future deprecation warnings should only apply to `#[rustc_deprecated]` as they take into account rustc's version. Fixes#57952.
I've also slightly modified rustdoc's display of future deprecation notices to make it more consistent, so I'm assigning a rustdoc team member for review to make sure this is okay.
r? @GuillaumeGomez
Cosmetic improvements to doc comments
This has been factored out from https://github.com/rust-lang/rust/pull/58036 to only include changes to documentation comments (throughout the rustc codebase).
r? @steveklabnik
Once you're happy with this, maybe we could get it through with r=1, so it doesn't constantly get invalidated? (I'm not sure this will be an issue, but just in case...) Anyway, thanks for your advice so far!
This commit builds on the fix from #58161 (which fixed miscompilation
caused by the introduction of `AscribeUserType` patterns for associated
constants) to start checking these patterns are well-formed for ranges
(previous fix just ignored them so that miscompilation wouldn't occur).
