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Prevent ICE on uninhabited MIR interpretation

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This commit is contained in:
Mark Rousskov 2020-09-01 10:55:49 -04:00
parent e023158145
commit 990a39596c
1 changed files with 6 additions and 1 deletions
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7
compiler/rustc_mir/src/interpret/cast.rs
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@ -139,9 +139,14 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
// # First handle non-scalar source values.
// Handle cast from a univariant (ZST) enum.
// Handle cast from a ZST enum (0 or 1 variants).
match src.layout.variants {
Variants::Single { index } => {
if src.layout.abi.is_uninhabited() {
// This is dead code, because an uninhabited enum is UB to
// instantiate.
throw_ub!(Unreachable);
}
if let Some(discr) = src.layout.ty.discriminant_for_variant(*self.tcx, index) {
assert!(src.layout.is_zst());
let discr_layout = self.layout_of(discr.ty)?;