Avoid invalidating the CFG in `MirPatch`
As a part of this change, we adjust `MirPatch` to not needlessly create unnecessary resume blocks.
r? `@tmiasko`
Always create elided lifetimes, even if inferred.
`PathSource` gives the context in which a path is encountered. The same `PathSource` is used for the full path and the `QSelf` part.
Therefore, we can only rely on `PathSource` to know whether typechecking will be able to infer the lifetimes, not whether we need to insert them at all.
Fixes https://github.com/rust-lang/rust/issues/99949
Some `is_useful` cleanups
#98582 was reverted because it was a perf regression.
https://github.com/rust-lang/rust/pull/99806 reintroduces the changes, but this PR picks individual ones that have no regressions.
Rollup of 6 pull requests
Successful merges:
- #98771 (Add support for link-flavor rust-lld for iOS, tvOS and watchOS)
- #98835 (relate `closure_substs.parent_substs()` to parent fn in NLL)
- #99746 (Use `TraitEngine` in more places that don't specifically need `FulfillmentContext::new_in_snapshot`)
- #99786 (Recover from C++ style `enum struct`)
- #99795 (Delay a bug when failed to normalize trait ref during specialization)
- #100029 (Prevent ICE for `doc_alias` on match arm, statement, expression)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
This is implementing the MCP from rust-lang/compiler-team#493. It is
increasing the minimum requirements of a couple Tier 1 targets, and
others at lower tiers, so this should go through FCP sign-offs for both
`T-compiler` and `T-release`.
The new `linux-gnu` baseline is kernel 3.2 and glibc 2.17. We will also
take that kernel as the minimum floor for _all_ `*-linux-*` targets, so
it may be broadly assumed in the implementation of the standard library.
That does not preclude specific targets from having greater requirements
where it makes sense, like a new arch needing something newer, or a
platform like `linux-android` choosing a newer baseline.
