bjoernager/rust
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'fieldless enums' is not what I meant -- it's empty/uninhabited enums, really

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This commit is contained in:
Ralf Jung 2020-03-02 11:45:02 +01:00
parent 96bb8b31c8
commit 6548be2ba9
2 changed files with 2 additions and 3 deletions
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3
src/librustc_mir/interpret/validity.rs
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@ -579,13 +579,12 @@ impl<'rt, 'mir, 'tcx, M: Machine<'mir, 'tcx>> ValueVisitor<'mir, 'tcx, M>
} }
// Check primitive types. We do this after checking for uninhabited types, // Check primitive types. We do this after checking for uninhabited types,
// to exclude fieldless enums (that also appear as fieldless unions here). // to exclude uninhabited enums (that also appear as fieldless unions here).
// Primitives can have varying layout, so we check them separately and before aggregate // Primitives can have varying layout, so we check them separately and before aggregate
// handling. // handling.
// It is CRITICAL that we get this check right, or we might be validating the wrong thing! // It is CRITICAL that we get this check right, or we might be validating the wrong thing!
let primitive = match op.layout.fields { let primitive = match op.layout.fields {
// Primitives appear as Union with 0 fields - except for Boxes and fat pointers. // Primitives appear as Union with 0 fields - except for Boxes and fat pointers.
// (Fieldless enums also appear here, but they are uninhabited and thus handled above.)
layout::FieldPlacement::Union(0) => true, layout::FieldPlacement::Union(0) => true,
_ => op.layout.ty.builtin_deref(true).is_some(), _ => op.layout.ty.builtin_deref(true).is_some(),
}; };

2
src/librustc_target/abi/mod.rs
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@ -872,7 +872,7 @@ impl Niche {
#[derive(PartialEq, Eq, Hash, Debug, HashStable_Generic)] #[derive(PartialEq, Eq, Hash, Debug, HashStable_Generic)]
pub struct LayoutDetails { pub struct LayoutDetails {
/// Says where the fields are located within the layout. /// Says where the fields are located within the layout.
/// Primitives and fieldless enums appear as unions without fields. /// Primitives and uninhabited enums appear as unions without fields.
pub fields: FieldPlacement, pub fields: FieldPlacement,
/// Encodes information about multi-variant layouts. /// Encodes information about multi-variant layouts.