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
rustdoc: remove unused derives and variants
Though many structs in rustdoc derive `RustcEncodable` and `RustcDecodable`, the impls do not appear to be used by the crate or its dependents. Removing them revealed some enum variants that are never constructed, too.
r? @GuillaumeGomez
Use a more efficient iteration order for backward dataflow
This applies the same basic principle as #62062 to the reverse dataflow analysis used to compute liveness information. It is functionally equivalent, except that post-order is used instead of reverse post-order.
In the long-term, `BitDenotation` should probably be extended to support both forward and backward dataflow, but there's some more work needed to get to that point.
Use a more efficient iteration order for forward dataflow
Currently, dataflow begins by visiting each block in order of ID (`BasicBlock(0)`, `BasicBlock(1)`, etc.). This PR changes that initial iteration to reverse post-order (see [this blog post](https://eli.thegreenplace.net/2015/directed-graph-traversal-orderings-and-applications-to-data-flow-analysis/#data-flow-analysis) for more info). This ensures that the effects of all predecessors will be applied before a basic block is visited if the CFG has no back-edges, and should result in less total iterations even when back-edges exist. This should not change the results of dataflow analysis.
The current ordering for basic blocks may be pretty close to RPO already--`BasicBlock(0)` is already the start block--in which case the cost of doing the traversal up front will outweigh the efficiency gains.
A perf run is needed to check this.
r? @pnkfelix (I think).
Clean up query cache code
There are a couple of queries for which we do not promote saved results, which have been removed from caching here. This was likely the cause of the regression in https://github.com/rust-lang/rust/pull/57293#issuecomment-476421298.
r? @michaelwoerister
Update musl to 1.1.22
This is the latest available version. I noticed Rust wasn't using the
latest version when I attempted to have Cargo link object files produced
outside of Cargo / Rust's toolchain and was getting missing symbol
errors. Those missing symbols were added in 1.1.21 and 1.1.22.
I'm not fully sure of the implications of this change or how
comprehensive the test coverage is. Upstream changes in 1.1.21 and
1.1.22 can be found at
https://git.musl-libc.org/cgit/musl/tree/WHATSNEW?h=v1.1.22&id=e97681d6f2c44bf5fa9ecdd30607cb63c780062e#n1989.
Normalization can leave some type-vars unresolved in its return type.
Make sure to resolve them so we have an infcx-independent type that can
be used with `needs_drop`.
Fixes#61402.
