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Auto merge of #100726 - jswrenn:transmute, r=oli-obk

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safe transmute: use `Assume` struct to provide analysis options

This task was left as a TODO in #92268; resolving it brings [`BikeshedIntrinsicFrom`](https://doc.rust-lang.org/nightly/core/mem/trait.BikeshedIntrinsicFrom.html) more in line with the API defined in [MCP411](https://github.com/rust-lang/compiler-team/issues/411).

**Before:**
```rust
pub unsafe trait BikeshedIntrinsicFrom<
    Src,
    Context,
    const ASSUME_ALIGNMENT: bool,
    const ASSUME_LIFETIMES: bool,
    const ASSUME_VALIDITY: bool,
    const ASSUME_VISIBILITY: bool,
> where
    Src: ?Sized,
{}
```
**After:**
```rust
pub unsafe trait BikeshedIntrinsicFrom<Src, Context, const ASSUME: Assume = { Assume::NOTHING }>
where
    Src: ?Sized,
{}
```

`Assume::visibility` has also been renamed to `Assume::safety`, as library safety invariants are what's actually being assumed; visibility is just the mechanism by which it is currently checked (and that may change).

r? `@oli-obk`

---

Related:
- https://github.com/rust-lang/compiler-team/issues/411
- https://github.com/rust-lang/rust/issues/99571
This commit is contained in:
bors 2022-09-04 07:55:44 +00:00
commit 8521a8c92d
79 changed files with 1320 additions and 735 deletions
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1
compiler/rustc_transmute/src/layout/dfa.rs
View file

@ -104,7 +104,6 @@ where
}
#[instrument(level = "debug")]
#[cfg_attr(feature = "rustc", allow(rustc::potential_query_instability))]
pub(crate) fn from_nfa(nfa: Nfa<R>) -> Self {
let Nfa { transitions: nfa_transitions, start: nfa_start, accepting: nfa_accepting } = nfa;

6
compiler/rustc_transmute/src/layout/nfa.rs
View file

@ -119,8 +119,6 @@ where
let mut transitions: Map<State, Map<Transition<R>, Set<State>>> = self.transitions;
// the iteration order doesn't matter
#[cfg_attr(feature = "rustc", allow(rustc::potential_query_instability))]
for (source, transition) in other.transitions {
let fix_state = |state| if state == other.start { self.accepting } else { state };
let entry = transitions.entry(fix_state(source)).or_default();
@ -142,8 +140,6 @@ where
let mut transitions: Map<State, Map<Transition<R>, Set<State>>> = self.transitions.clone();
// the iteration order doesn't matter
#[cfg_attr(feature = "rustc", allow(rustc::potential_query_instability))]
for (&(mut source), transition) in other.transitions.iter() {
// if source is starting state of `other`, replace with starting state of `self`
if source == other.start {
@ -152,8 +148,6 @@ where
let entry = transitions.entry(source).or_default();
for (edge, destinations) in transition {
let entry = entry.entry(edge.clone()).or_default();
// the iteration order doesn't matter
#[cfg_attr(feature = "rustc", allow(rustc::potential_query_instability))]
for &(mut destination) in destinations {
// if dest is accepting state of `other`, replace with accepting state of `self`
if destination == other.accepting {