Prefer accessible paths in 'use' suggestions
This PR addresses issue https://github.com/rust-lang/rust/issues/26454, where `use` suggestions are made for paths that don't work. For example:
```rust
mod foo {
mod bar {
struct X;
}
}
fn main() { X; } // suggests `use foo::bar::X;`
```
Cache flags and escaping vars for predicates
With predicates becoming interned (rust-lang/compiler-team#285) this is now possible and could be a perf win. It would become an even larger win once we have recursive predicates.
cc @lcnr @nikomatsakis
r? @ghost
Upgrade Chalk
Things done in this PR:
- Upgrade Chalk to `0.11.0`
- Added compare-mode=chalk
- Bump rustc-hash in `librustc_data_structures` to `1.1.0` to match Chalk
- Removed `RustDefId` since the builtin type support is there
- Add a few more `FIXME(chalk)`s for problem spots I hit when running all tests with chalk
- Added some more implementation code for some newer builtin Chalk types (e.g. `FnDef`, `Array`)
- Lower `RegionOutlives` and `ObjectSafe` predicates
- Lower `Dyn` without the region
- Handle `Int`/`Float` `CanonicalVarKind`s
- Uncomment some Chalk tests that actually work now
- Remove the revisions in `src/test/ui/coherence/coherence-subtyping.rs` since they aren't doing anything different
r? @nikomatsakis
This fixes an issue with the following sample:
mod foo {
mod inaccessible {
pub struct X;
}
pub mod avail {
pub struct X;
}
}
fn main() { X; }
Instead of suggesting both `use crate::foo::inaccessible::X;` and `use
crate::foo::avail::X;`, it should only suggest the latter.
It is done by trimming the list of suggestions from inaccessible paths
if accessible paths are present.
Visibility is checked with `is_accessible_from` now instead of being
hard-coded.
-
Some tests fixes are trivial, and others require a bit more explaining,
here are my comments:
src/test/ui/issues/issue-35675.stderr: Only needs to make the enum
public to have the suggestion make sense.
src/test/ui/issues/issue-42944.stderr: Importing the tuple struct won't
help because its constructor is not visible, so the attempted
constructor does not work. In that case, it's better not to suggest it.
The case where the constructor is public is covered in `issue-26545.rs`.
Enable LLVM zlib
Compilers may generate ELF objects with compressed sections (although rustc currently doesn't do this). Currently, when linking these with `rust-lld`, you'll get this error:
`rust-lld: error: ...: contains a compressed section, but zlib is not available`
This enables zlib when building LLVM.
Add a lint to catch clashing `extern` fn declarations.
Closes#69390.
Adds lint `clashing_extern_decl` to detect when, within a single crate, an extern function of the same name is declared with different types. Because two symbols of the same name cannot be resolved to two different functions at link time, and one function cannot possibly have two types, a clashing extern declaration is almost certainly a mistake.
This lint does not run between crates because a project may have dependencies which both rely on the same extern function, but declare it in a different (but valid) way. For example, they may both declare an opaque type for one or more of the arguments (which would end up distinct types), or use types that are valid conversions in the language the extern fn is defined in. In these cases, we can't say that the clashing declaration is incorrect.
r? @eddyb
ci: allow gating GHA on everything but macOS
In our GitHub Actions setup macOS is too unreliable to gate on it, but the other builders work fine. This commit splits the macOS builders into a separate job (called `auto-fallible`), allowing us to gate on the auto job without failing due to macOS spurious failures.
cc https://github.com/rust-lang/rust-central-station/issues/848
r? @Mark-Simulacrum
Pre-compute `LocalDefId` <-> `HirId` mappings and remove `NodeId` <-> `HirId` conversion APIs
cc #50928
I don't know who is exactly the best person to review this.
r? @petrochenkov
lint: normalize projections using opaque types
Fixes#73251.
This PR normalizes projections which use opaque types (opaque types are otherwise linted against, which is would have previously made the test cases added in this PR fail).
core/time: Add Duration methods for zero
This patch adds two methods to `Duration`. The first, `Duration::zero`,
provides a `const` constructor for getting an zero-length duration. This
is also what `Default` provides (this was clarified in the docs), though
`default` is not `const`.
The second, `Duration::is_zero`, returns true if a `Duration` spans no
time (i.e., because its components are all zero). Previously, the way to
do this was either to compare both `as_secs` and `subsec_nanos` to 0, to
compare against `Duration::new(0, 0)`, or to use the `u128` method
`as_nanos`, none of which were particularly elegant.
Projection bound validation
During selection we use bounds declared on associated types (e.g. `type X: Copy`) to satisfy trait/projection bounds. This would be fine so long as those bounds are checked on any impls/trait objects. For simple cases they are because the bound `Self::X: Copy` gets normalized when we check the impl.
However, for default values with specialization and higher-ranked bounds from GATs or otherwise, we can't normalize when checking the impl, and so we use the bound from the trait to prove that the bound applies to the impl, which is clearly unsound.
This PR makes 2 fixes for this:
1. Requiring that the bounds on the trait apply to a projection type with the corresponding substs, so a bound `for<'a> <Self as X<'a>>::U: Copy` on the trait cannot be used to prove `<T as X<'_>>::U: Copy`.
2. Actually checking that the bounds that we still allow apply to generic/default associated types.
Opening for a crater run.
Closes#68641Closes#68642Closes#68643Closes#68644Closes#68645Closes#68656
r? @ghost
Try to suggest dereferences on trait selection failed
Fixes#39029Fixes#62530
This PR consists of two parts:
1. Decouple `Autoderef` with `FnCtxt` and move `Autoderef` to `librustc_trait_selection`.
2. Try to suggest dereferences when trait selection failed.
The first is needed because:
1. For suggesting dereferences, the struct `Autoderef` should be used. But before this PR, it is placed in `librustc_typeck`, which depends on `librustc_trait_selection`. But trait selection error emitting happens in `librustc_trait_selection`, if we want to use `Autoderef` in it, dependency loop is inevitable. So I moved the `Autoderef` to `librustc_trait_selection`.
2. Before this PR, `FnCtxt` is coupled to `Autoderef`, and `FnCtxt` only exists in `librustc_typeck`. So decoupling is needed.
After this PR, we can get suggestion like this:
```
error[E0277]: the trait bound `&Baz: Happy` is not satisfied
--> $DIR/trait-suggest-deferences-multiple.rs:34:9
|
LL | fn foo<T>(_: T) where T: Happy {}
| ----- required by this bound in `foo`
...
LL | foo(&baz);
| ^^^^
| |
| the trait `Happy` is not implemented for `&Baz`
| help: consider adding dereference here: `&***baz`
error: aborting due to previous error
For more information about this error, try `rustc --explain E0277`.
```
r? @estebank
