bjoernager/rust
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Split Single ctor into more specific variants

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This commit is contained in:
Nadrieril 2023-12-11 13:32:34 +01:00
parent 4d1bd0db7f
commit b111b2e839
4 changed files with 80 additions and 52 deletions
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9
compiler/rustc_pattern_analysis/src/usefulness.rs
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@ -629,12 +629,9 @@ impl ValidityConstraint {
///
/// Pending further opsem decisions, the current behavior is: validity is preserved, except
/// inside `&` and union fields where validity is reset to `MaybeInvalid`.
fn specialize<'tcx>(self, pcx: &PatCtxt<'_, '_, 'tcx>, ctor: &Constructor<'tcx>) -> Self {
fn specialize(self, ctor: &Constructor<'_>) -> Self {
// We preserve validity except when we go inside a reference or a union field.
if matches!(ctor, Constructor::Single)
&& (matches!(pcx.ty.kind(), ty::Ref(..))
|| matches!(pcx.ty.kind(), ty::Adt(def, ..) if def.is_union()))
{
if matches!(ctor, Constructor::Ref | Constructor::UnionField) {
// Validity of `x: &T` does not imply validity of `*x: T`.
MaybeInvalid
} else {
@ -902,7 +899,7 @@ impl<'p, 'tcx> Matrix<'p, 'tcx> {
ctor: &Constructor<'tcx>,
) -> Matrix<'p, 'tcx> {
let wildcard_row = self.wildcard_row.pop_head_constructor(pcx, ctor);
let new_validity = self.place_validity[0].specialize(pcx, ctor);
let new_validity = self.place_validity[0].specialize(ctor);
let new_place_validity = std::iter::repeat(new_validity)
.take(ctor.arity(pcx))
.chain(self.place_validity[1..].iter().copied())