bjoernager/rust
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Allow transmutes between the same types after erasing lifetimes

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This commit is contained in:
Oli Scherer 2022-09-07 07:51:11 +00:00
parent 5854680388
commit d90d055691
6 changed files with 43 additions and 27 deletions
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20
compiler/rustc_hir_analysis/src/check/intrinsicck.rs
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@ -44,13 +44,23 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
pub fn check_transmute(&self, from: Ty<'tcx>, to: Ty<'tcx>, hir_id: HirId) {
let tcx = self.tcx;
let span = tcx.hir().span(hir_id);
let convert = |ty: Ty<'tcx>| {
let normalize = |ty| {
let ty = self.resolve_vars_if_possible(ty);
let ty = tcx.normalize_erasing_regions(self.param_env, ty);
(SizeSkeleton::compute(ty, tcx, self.param_env), ty)
self.tcx.normalize_erasing_regions(self.param_env, ty)
};
let (sk_from, from) = convert(from);
let (sk_to, to) = convert(to);
let from = normalize(from);
let to = normalize(to);
trace!(?from, ?to);
// Transmutes that are only changing lifetimes are always ok.
if from == to {
return;
}
let skel = |ty| SizeSkeleton::compute(ty, tcx, self.param_env);
let sk_from = skel(from);
let sk_to = skel(to);
trace!(?sk_from, ?sk_to);
// Check for same size using the skeletons.
if let (Ok(sk_from), Ok(sk_to)) = (sk_from, sk_to) {