bjoernager/rust
bjoernager/rust
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have better explanation for relate_types

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This commit is contained in:
ouz-a 2023-10-02 11:22:48 +03:00
parent 6f0c5ee2d4
commit 5d753abb30
13 changed files with 40 additions and 34 deletions
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21
compiler/rustc_mir_transform/src/add_subtyping_projections.rs
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@ -24,24 +24,31 @@ impl<'a, 'tcx> MutVisitor<'tcx> for SubTypeChecker<'a, 'tcx> {
rvalue: &mut Rvalue<'tcx>,
location: Location,
) {
let place_ty = place.ty(self.local_decls, self.tcx);
let mut place_ty = place.ty(self.local_decls, self.tcx).ty;
let mut rval_ty = rvalue.ty(self.local_decls, self.tcx);
if place_ty.ty != rval_ty {
// Not erasing this causes `Free Regions` errors in validator,
// when rval is `ReStatic`.
rval_ty = self.tcx.erase_regions_ty(rval_ty);
// Not erasing this causes `Free Regions` errors in validator,
// when rval is `ReStatic`.
rval_ty = self.tcx.erase_regions_ty(rval_ty);
place_ty = self.tcx.erase_regions(place_ty);
if place_ty != rval_ty {
let temp = self
.patcher
.new_temp(rval_ty, self.local_decls[place.as_ref().local].source_info.span);
let new_place = Place::from(temp);
self.patcher.add_assign(location, new_place, rvalue.clone());
let subtyped =
new_place.project_deeper(&[ProjectionElem::Subtype(place_ty.ty)], self.tcx);
let subtyped = new_place.project_deeper(&[ProjectionElem::Subtype(place_ty)], self.tcx);
*rvalue = Rvalue::Use(Operand::Move(subtyped));
}
}
}
// Aim here is to do this kind of transformation:
//
// let place: place_ty = rval;
// // gets transformed to
// let temp: rval_ty = rval;
// let place: place_ty = temp as place_ty;
//
pub fn subtype_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
let patch = MirPatch::new(body);
let mut checker = SubTypeChecker { tcx, patcher: patch, local_decls: &body.local_decls };