parser: Keep current and previous tokens precisely
...including their unnormalized forms.
Add more documentation for them.
Hopefully, this will help to eliminate footguns like https://github.com/rust-lang/rust/pull/68728#discussion_r373787486.
I'll try to address the FIXMEs in separate PRs during the next week.
r? @Centril
Make `num::NonZeroX::new` an unstable `const fn`
cc #53718
These require `#[feature(const_if_match)]`, meaning they must remain unstable for the time being.
Reduce the number of `RefCell`s in `InferCtxt`.
`InferCtxt` contains six structures within `RefCell`s. Every time we
create and dispose of (commit or rollback) a snapshot we have to
`borrow_mut` each one of them.
This commit moves the six structures under a single `RefCell`, which
gives significant speed-ups by reducing the number of `borrow_mut`
calls. To avoid runtime errors I had to reduce the lifetimes of dynamic
borrows in a couple of places.
r? @varkor
Fixes#67844
Previously, opaque types would only get parent generics if they
a return-position-impl-trait (e.g. `fn foo<A>() -> impl MyTrait<A>`).
However, it's possible for opaque types to be nested inside one another:
```rust
trait WithAssoc { type AssocType; }
trait WithParam<A> {}
type Return<A> = impl WithAssoc<AssocType = impl WithParam<A>>;
```
When this occurs, we need to ensure that the nested opaque types
properly inherit generic parameters from their parent opaque type.
This commit fixes the `generics_of` query to take the parent item
into account when determining the generics for an opaque type.
This was previously a future-compat warning that has since been turned into
hard error, but without actually removing all the code.
Avoids a call to `traits::overlapping_impls`, which is expensive.
This has negligible perf impact, but it does improve the code a bit.
* Only query the specialization graph of any trait once instead of once per
impl
* Loop over impls only once, precomputing impl DefId and TraitRef
Improve reporting errors and suggestions for trait bounds
Fix#66802
- When printing errors for unsized function parameter, properly point at the parameter instead of function's body.
- Improve `consider further restricting this bound` (and related) messages by separating human-oriented hints from the machine-oriented ones.
`InferCtxt` contains six structures within `RefCell`s. Every time we
create and dispose of (commit or rollback) a snapshot we have to
`borrow_mut` each one of them.
This commit moves the six structures under a single `RefCell`, which
gives significant speed-ups by reducing the number of `borrow_mut`
calls. To avoid runtime errors I had to reduce the lifetimes of dynamic
borrows in a couple of places.
Rollup of 5 pull requests
Successful merges:
- #68738 (Derive Clone + Eq for std::string::FromUtf8Error)
- #68742 (implement AsMut<str> for String)
- #68881 (rustc_codegen_llvm: always set AlwaysPreserve on all debuginfo variables)
- #68911 (Speed up the inherent impl overlap check)
- #68913 (Pretty-print generic params and where clauses on associated types)
Failed merges:
r? @ghost
Now the line for each statement will show the diff resulting from the
combination of `before_statement_effect` and `statement_effect`. It's
still possible to observe each in isolation via
`borrowck_graphviz_format = "two_phase"`.
rustc_codegen_llvm: always set AlwaysPreserve on all debuginfo variables
Making this depend on the optimization level appears to have been a copy-paste mistake (other LLVM functions called in this module also take a `bool` argument, but there it means something unrelated).
Also see https://github.com/rust-lang/rust/pull/8855#discussion_r374392128.
I don't believe we have any reason to let LLVM omit user variables from DWARF, and we were already setting this to `true` when LLVM *could* optimize them away, so this PR should have no effect anyway.
r? @michaelwoerister or @nagisa cc @hanna-kruppe @nikomatsakis
Derive Clone + Eq for std::string::FromUtf8Error
Implement `Clone` and `Eq` for `std::string::FromUtf8Error`.
Both the inner `Vec<u8>` and `std::str::Utf8Error` are also `Clone + Eq`, so I don't see why we shouldn't derive them on `FromUtf8Error` as well.
(impl are insta-stable, requiring FCP from T-libs.)
Add an option to use LLD to link the compiler on Windows platforms
Based on https://github.com/rust-lang/rust/pull/68609.
Using LLD is good way to improve compile times on Windows since `link.exe` is quite slow. The time for `x.py build --stage 1 src/libtest` goes from 0:12:00 to 0:08:29. Compile time for `rustc_driver` goes from 226.34s to 18.5s. `rustc_macros` goes from 28.69s to 7.7s. The size of `rustc_driver` is also reduced from 83.3 MB to 78.7 MB.
r? @Mark-Simulacrum
Rollup of 7 pull requests
Successful merges:
- #68718 (Move `rustc_hir::def_id` to `rustc_span::def_id`)
- #68834 (Fix and test implementation of BTreeMap's first/last_entry, pop_first/last)
- #68857 (perf: Reduce Vec allocations in normalization by passing &mut Vec)
- #68918 (Don't use the word "unwrap" to describe "unwrap" methods)
- #68946 (Mark several functions and methods in core::cmp as #[must_use])
- #68958 (Clean up E0277 and E0282 explanations)
- #68960 (codegen: misc cleanups around debuginfo scopes and locations.)
Failed merges:
r? @ghost
When suggesting associated fn with type parameters, include in the structured suggestion
Address #50734.
```
error[E0046]: not all trait items implemented, missing: `foo`, `bar`, `baz`
--> file.rs:14:1
|
14 | impl TraitA<()> for S {
| ^^^^^^^^^^^^^^^^^^^^^ missing `foo`, `bar`, `baz` in implementation
|
= help: implement the missing item: `fn foo<T>(_: T) -> Self where T: TraitB, TraitB::Item = A { unimplemented!() }`
= help: implement the missing item: `fn bar<T>(_: T) -> Self { unimplemented!() }`
= help: implement the missing item: `fn baz<T>(_: T) -> Self where T: TraitB, <T as TraitB>::Item: std::marker::Copy { unimplemented!() }`
```
It doesn't work well for associated types with `ty::Predicate::Projection`s as we need to resugar `T: Trait, Trait::Assoc = K` → `T: Trait<Assoc = K>`.
Initial implementation of `#![feature(move_ref_pattern)]`
Following up on #45600, under the gate `#![feature(move_ref_pattern)]`, `(ref x, mut y)` is allowed subject to restrictions necessary for soundness. The match checking implementation and tests for `#![feature(bindings_after_at)]` is also adjusted as necessary.
Closes#45600.
Tracking issue: #68354.
r? @matthewjasper
