Rollup of 8 pull requests
Successful merges:
- #62062 (Use a more efficient iteration order for forward dataflow)
- #62063 (Use a more efficient iteration order for backward dataflow)
- #62224 (rustdoc: remove unused derives and variants)
- #62228 (Extend the #[must_use] lint to boxed types)
- #62235 (Extend the `#[must_use]` lint to arrays)
- #62239 (Fix a typo)
- #62241 (Always parse 'async unsafe fn' + properly ban in 2015)
- #62248 (before_exec actually will only get deprecated with 1.37)
Failed merges:
r? @ghost
Stabilize `type_alias_enum_variants` in Rust 1.37.0
Stabilize `#![feature(type_alias_enum_variants)]` which allows type-relative resolution with highest priority to `enum` variants in both expression and pattern contexts. For example, you may now write:
```rust
enum Option<T> {
None,
Some(T),
}
type OptAlias<T> = Option<T>;
fn work_on_alias(x: Option<u8>) -> u8 {
match x {
OptAlias::Some(y) => y + 1,
OptAlias::None => 0,
}
}
```
Closes https://github.com/rust-lang/rfcs/issues/2218
Closes https://github.com/rust-lang/rust/issues/52118
r? @petrochenkov
Add `--pass $mode` to compiletest through `./x.py`
Adds a flag `--pass $mode` to compiletest, which is exposed through `./x.py`.
When `--pass $mode` is passed, `{check,build,compile,run}-pass` tests will be forced to run under the given `$mode` unless the directive `// ignore-pass` exists in the test file.
The modes are explained in https://github.com/rust-lang/rust/pull/61778:
- `check` has the same effect as `cargo check`
- `build` or `compile` have the same effect as `cargo build`
- `run` has the same effect as `cargo run`
On my machine, `./x.py -i test src/test/run-pass --stage 1 --pass check` takes 38 seconds whereas it takes 2 min 7 seconds without `--pass check`.
cc https://github.com/rust-lang/rust/issues/61712
r? @petrochenkov
Don't ICE on item in `.await` expression
The code for lowering a `.await` expression missed that item IDs may already have been assigned for items inside of an `async` block, or for closures. This change means we no longer exit early after finding a `.await` in a block that isn't `async` and instead just emit the error. This avoids an ICE generated due to item IDs not being densely generated. (The `YieldSource` of the generated `yield` expression is used to avoid errors generated about having `yield` expressions outside of generator literals.)
r? @cramertj
Resolves#62009 and resolves#61685
Clean up MIR drop generation
* Don't assign twice to the destination of a `while` loop containing a `break` expression
* Use `as_temp` to evaluate statement expression
* Avoid consecutive `StorageLive`s for the condition of a `while` loop
* Unify `return`, `break` and `continue` handling, and move it to `scopes.rs`
* Make some of the `scopes.rs` internals private
* Don't use `Place`s that are always `Local`s in MIR drop generation
Closes#42371Closes#61579Closes#61731Closes#61834Closes#61910Closes#62115
rustc: correctly transform memory_index mappings for generators.
Fixes#61793, closes#62011 (previous attempt at fixing #61793).
During #60187, I made the mistake of suggesting that the (re-)computation of `memory_index` in `ty::layout`, after generator-specific logic split/recombined fields, be done off of the `offsets` of those fields (which needed to be computed anyway), as opposed to the `memory_index`.
`memory_index` maps each field to its in-memory order index, which ranges over the same `0..n` values as the fields themselves, making it a bijective mapping, and more specifically a permutation (indeed, it's the permutation resulting from field reordering optimizations).
Each field has an unique "memory index", meaning a sort based on them, even an unstable one, will not put them in the wrong order. But offsets don't have that property, because of ZSTs (which do not increase the offset), so sorting based on the offset of fields alone can (and did) result in wrong orders.
Instead of going back to sorting based on (slices/subsets of) `memory_index`, or special-casing ZSTs to make sorting based on offsets produce the right results (presumably), as #62011 does, I opted to drop sorting altogether and focus on `O(n)` operations involving *permutations*:
* a permutation is easily inverted (see the `invert_mapping` `fn`)
* an `inverse_memory_index` was already employed in other parts of the `ty::layout` code (that is, a mapping from memory order to field indices)
* inverting twice produces the original permutation, so you can invert, modify, and invert again, if it's easier to modify the inverse mapping than the direct one
* you can modify/remove elements in a permutation, as long as the result remains dense (i.e. using every integer in `0..len`, without gaps)
* for splitting a `0..n` permutation into disjoint `0..x` and `x..n` ranges, you can pick the elements based on a `i < x` / `i >= x` predicate, and for the latter, also subtract `x` to compact the range to `0..n-x`
* in the general case, for taking an arbitrary subset of the permutation, you need a renumbering from that subset to a dense `0..subset.len()` - but notably, this is still `O(n)`!
* you can merge permutations, as long as the result remains disjoint (i.e. each element is unique)
* for concatenating two `0..n` and `0..m` permutations, you can renumber the elements in the latter to `n..n+m`
* some of these operations can be combined, and an inverse mapping (be it a permutation or not) can still be used instead of a forward one by changing the "domain" of the loop performing the operation
I wish I had a nicer / more mathematical description of the recombinations involved, but my focus was to fix the bug (in a way which preserves information more directly than sorting would), so I may have missed potential changes in the surrounding generator layout code, that would make this all more straight-forward.
r? @tmandry
Rollup of 7 pull requests
Successful merges:
- #61814 (Fix an ICE with uninhabited consts)
- #61987 (rustc: produce AST instead of HIR from `hir::lowering::Resolver` methods.)
- #62055 (Fix error counting)
- #62078 (Remove built-in derive macros `Send` and `Sync`)
- #62085 (Add test for issue-38591)
- #62091 (HirIdification: almost there)
- #62096 (Implement From<Local> for Place and PlaceBase)
Failed merges:
r? @ghost
Fix error counting
Count duplicate errors for `track_errors` and other error counting checks.
Add FIXMEs to make it clear that we should be moving away from this kind of logic.
Closes#61663
Refactor miri pointer checks
Centralize bounds, alignment and NULL checking for memory accesses in one function: `memory.check_ptr_access`. That function also takes care of converting a `Scalar` to a `Pointer`, should that be needed. Not all accesses need that though: if the access has size 0, `None` is returned. Everyone accessing memory based on a `Scalar` should use this method to get the `Pointer` they need.
All operations on the `Allocation` work on `Pointer` inputs and expect all the checks to have happened (and will ICE if the bounds are violated). The operations on `Memory` work on `Scalar` inputs and do the checks themselves.
The only other public method to check pointers is `memory.ptr_may_be_null`, which is needed in a few places. No need for `check_align` or similar methods. That makes the public API surface much easier to use and harder to mis-use.
This should be largely no-functional-change, except that ZST accesses to a "true" pointer that is dangling or out-of-bounds are now considered UB. This is to be conservative wrt. whatever LLVM might be doing.
While I am at it, this also removes the assumption that the vtable part of a `dyn Trait`-fat-pointer is a `Pointer` (as opposed to a pointer cast to an integer, stored as raw bits).
r? @oli-obk
compiletest: Introduce `// {check,build,run}-pass` pass modes
Pass UI tests now have three modes
```
// check-pass
// build-pass
// run-pass
```
mirroring equivalent well-known `cargo` commands.
`// check-pass` will compile the test skipping codegen (which is expensive and isn't supposed to fail in most cases).
`// build-pass` will compile and link the test without running it.
`// run-pass` will compile, link and run the test.
Tests without a "pass" annotation are still considered "fail" tests.
Most UI tests would probably want to switch to `check-pass`.
Tests validating codegen would probably want to run the generated code as well and use `run-pass`.
`build-pass` should probably be rare (linking tests?).
https://github.com/rust-lang/rust/pull/61755 will provide a way to run the tests with any mode, e.g. bump `check-pass` tests to `run-pass` to satisfy especially suspicious people, and be able to make sure that codegen doesn't breaks in some entirely unexpected way.
Tests marked with any mode are expected to pass with any other mode, if that's not the case for some legitimate reason, then the test should be made a "fail" test rather than a "pass" test.
Perhaps some secondary CI can verify this invariant, but that's not super urgent.
`// compile-pass` still works and is equivalent to `build-pass`.
Why is `// compile-pass` bad - 1) it gives an impression that the test is only compiled, but not linked, 2) it doesn't mirror a cargo command.
It can be removed some time in the future in a separate PR.
cc https://github.com/rust-lang/rust/issues/61712
[let_chains, 2/6] Introduce `Let(..)` in AST, remove IfLet + WhileLet and parse let chains
Here we remove `ast::ExprKind::{IfLet, WhileLet}` and introduce `ast::ExprKind::Let`.
Moreover, we also:
+ connect the parsing logic for let chains
+ introduce the feature gate
+ rewire HIR lowering a bit.
However, this does not connect the new syntax to semantics in HIR.
That will be the subject of a subsequent PR.
Per https://github.com/rust-lang/rust/issues/53667#issuecomment-471583239.
Next step after https://github.com/rust-lang/rust/pull/59288.
cc @Manishearth re. Clippy.
r? @oli-obk
Fix meta-variable binding errors in macros
The errors are either:
- The meta-variable used in the right-hand side is not bound (or defined) in the
left-hand side.
- The meta-variable used in the right-hand side does not repeat with the same
kleene operator as its binder in the left-hand side. Either it does not repeat
enough, or it uses a different operator somewhere.
This change should have no semantic impact.
Found by https://github.com/rust-lang/rust/pull/62008
The errors are either:
- The meta-variable used in the right-hand side is not bound (or defined) in the
left-hand side.
- The meta-variable used in the right-hand side does not repeat with the same
kleene operator as its binder in the left-hand side. Either it does not repeat
enough, or it uses a different operator somewhere.
This change should have no semantic impact.
