where
T: GenKill<Local>,
{
+ fn visit_place(&mut self, place: &mir::Place<'tcx>, context: PlaceContext, location: Location) {
+ let mir::Place { projection, local } = *place;
+
+ // We purposefully do not call `super_place` here to avoid calling `visit_local` for this
+ // place with one of the `Projection` variants of `PlaceContext`.
+ self.visit_projection(local, projection, context, location);
+
+ match DefUse::for_place(context) {
+ // Treat derefs as a use of the base local. `*p = 4` is not a def of `p` but a use.
+ Some(_) if place.is_indirect() => self.0.gen(local),
+
+ Some(DefUse::Def) if projection.is_empty() => self.0.kill(local),
+ Some(DefUse::Use) => self.0.gen(local),
+ _ => {}
+ }
+ }
+
fn visit_local(&mut self, &local: &Local, context: PlaceContext, _: Location) {
+ // Because we do not call `super_place` above, `visit_local` is only called for locals that
+ // do not appear as part of a `Place` in the MIR. This handles cases like the implicit use
+ // of the return place in a `Return` terminator or the index in an `Index` projection.
match DefUse::for_place(context) {
Some(DefUse::Def) => self.0.kill(local),
Some(DefUse::Use) => self.0.gen(local),
| MutatingUseContext::AsmOutput
| MutatingUseContext::Borrow
| MutatingUseContext::Drop
- | MutatingUseContext::Projection
| MutatingUseContext::Retag,
)
| PlaceContext::NonMutatingUse(
| NonMutatingUseContext::Copy
| NonMutatingUseContext::Inspect
| NonMutatingUseContext::Move
- | NonMutatingUseContext::Projection
| NonMutatingUseContext::ShallowBorrow
| NonMutatingUseContext::SharedBorrow
| NonMutatingUseContext::UniqueBorrow,
) => Some(DefUse::Use),
+
+ PlaceContext::MutatingUse(MutatingUseContext::Projection)
+ | PlaceContext::NonMutatingUse(NonMutatingUseContext::Projection) => {
+ unreachable!("A projection could be a def or a use and must be handled separately")
+ }
}
}
}