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Only need TyErr for uninhabited types

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This commit is contained in:
Nadrieril 2020-04-13 17:45:12 +01:00
parent a5294b6486
commit 160eebec21
1 changed files with 4 additions and 4 deletions
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8
src/librustc_mir_build/hair/pattern/_match.rs
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@ -880,15 +880,15 @@ impl<'tcx> Constructor<'tcx> {
let ty = field.ty(cx.tcx, substs);
let is_visible = adt.is_enum()
|| field.vis.is_accessible_from(cx.module, cx.tcx);
let is_uninhabited = cx.is_uninhabited(ty);
// Treat all non-visible fields as `TyErr`. They can't appear
// in any other pattern from this match (because they are
let is_inhabited = !cx.is_uninhabited(ty);
// Treat all uninhabited non-visible fields as `TyErr`. They can't
// appear in any other pattern from this match (because they are
// private), so their type does not matter - but we don't want
// to know they are uninhabited.
// Also treat all uninhabited types in non-exhaustive variants as
// `TyErr`.
let allowed_to_inspect =
is_visible && !(is_non_exhaustive && is_uninhabited);
is_inhabited || (is_visible && !is_non_exhaustive);
if allowed_to_inspect {
Pat::wildcard_from_ty(ty)