bjoernager/rust
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Variants::Single: do not use invalid VariantIdx for uninhabited enums

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This commit is contained in:
Ralf Jung 2024-12-01 13:12:43 +01:00
parent 37e74596c0
commit 21de42bf8d
47 changed files with 549 additions and 281 deletions
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13
compiler/rustc_middle/src/ty/layout.rs
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@ -734,7 +734,7 @@ where
let layout = match this.variants {
Variants::Single { index }
// If all variants but one are uninhabited, the variant layout is the enum layout.
if index == variant_index &&
if index == Some(variant_index) &&
// Don't confuse variants of uninhabited enums with the enum itself.
// For more details see https://github.com/rust-lang/rust/issues/69763.
this.fields != FieldsShape::Primitive =>
@ -743,6 +743,8 @@ where
}
Variants::Single { index } => {
// `Single` variant enums *can* have other variants, but those are uninhabited.
let tcx = cx.tcx();
let typing_env = cx.typing_env();
@ -758,7 +760,7 @@ where
_ => bug!("`ty_and_layout_for_variant` on unexpected type {}", this.ty),
};
tcx.mk_layout(LayoutData {
variants: Variants::Single { index: variant_index },
variants: Variants::Single { index: Some(variant_index) },
fields: match NonZero::new(fields) {
Some(fields) => FieldsShape::Union(fields),
None => FieldsShape::Arbitrary { offsets: IndexVec::new(), memory_index: IndexVec::new() },
@ -775,7 +777,7 @@ where
Variants::Multiple { ref variants, .. } => cx.tcx().mk_layout(variants[variant_index].clone()),
};
assert_eq!(*layout.variants(), Variants::Single { index: variant_index });
assert_eq!(*layout.variants(), Variants::Single { index: Some(variant_index) });
TyAndLayout { ty: this.ty, layout }
}
@ -905,7 +907,7 @@ where
Variants::Single { index } => TyMaybeWithLayout::Ty(
args.as_coroutine()
.state_tys(def_id, tcx)
.nth(index.as_usize())
.nth(index.unwrap().as_usize())
.unwrap()
.nth(i)
.unwrap(),
@ -924,7 +926,8 @@ where
ty::Adt(def, args) => {
match this.variants {
Variants::Single { index } => {
let field = &def.variant(index).fields[FieldIdx::from_usize(i)];
let field =
&def.variant(index.unwrap()).fields[FieldIdx::from_usize(i)];
TyMaybeWithLayout::Ty(field.ty(tcx, args))
}