The commit should have changed comments as well.
At the time of writting, it passes the tidy and check tool.
Revisions asked by eddyb :
- Renamed of all the occurences of {visit/super}_mir
- Renamed test structures `CachedMir` to `Cached`
Fixing the missing import on `AggregateKind`
This commit extends previous work to kill borrows from a local after
assignment into that local to kill borrows from a projection after
assignment into a prefix of that place.
Previously, we would split the drop access into multiple checks for each
field of a struct/tuple/closure and through `Box` dereferences. This
changes this to check if the borrow is accessed by the drop in
places_conflict.
This also allows us to handle enums in a simpler way, since we don't
have to construct any new places.
```rust
fn main() {
fn reuse<X>(_: &mut X) {}
let mut t = 2f64;
match t {
ref mut _b if { false } => { reuse(_b); }
_ => {}
}
}
```
Note: The way this is currently written is confusing; when `autoref`
is off, then the arm body bindings (introduced by
`bind_matched_candidate_for_arm_body`) are *also* used for the guard.
(Any attempt to fix this needs to still ensure that the bindings used
by the guard are introduced before the guard is evaluated.)
(Once we turn NLL on by default, we can presumably simplify all of
that.)
