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Pattern types have their base type as a field

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This commit is contained in:
Oli Scherer 2025-10-21 10:17:38 +00:00
parent e821cb8dd9
commit d9f22d289c
4 changed files with 53 additions and 6 deletions
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6
compiler/rustc_middle/src/ty/layout.rs
View file

@ -839,11 +839,15 @@ where
| ty::FnDef(..)
| ty::CoroutineWitness(..)
| ty::Foreign(..)
| ty::Pat(_, _)
| ty::Dynamic(_, _) => {
bug!("TyAndLayout::field({:?}): not applicable", this)
}
ty::Pat(base, _) => {
assert_eq!(i, 0);
TyMaybeWithLayout::Ty(base)
}
ty::UnsafeBinder(bound_ty) => {
let ty = tcx.instantiate_bound_regions_with_erased(bound_ty.into());
field_ty_or_layout(TyAndLayout { ty, ..this }, cx, i)

8
compiler/rustc_ty_utils/src/layout.rs
View file

@ -350,6 +350,14 @@ fn layout_of_uncached<'tcx>(
ty::PatternKind::Or(..) => bug!("patterns cannot have nested or patterns"),
},
}
// Pattern types contain their base as their sole field.
// This allows the rest of the compiler to process pattern types just like
// single field transparent Adts, and only the parts of the compiler that
// specifically care about pattern types will have to handle it.
layout.fields = FieldsShape::Arbitrary {
offsets: [Size::ZERO].into_iter().collect(),
memory_index: [0].into_iter().collect(),
};
tcx.mk_layout(layout)
}

18
tests/ui/type/pattern_types/or_patterns.stderr
View file

@ -53,7 +53,14 @@ error: layout_of((i8) is (i8::MIN..=-1 | 1..)) = Layout {
valid_range: 1..=255,
},
),
fields: Primitive,
fields: Arbitrary {
offsets: [
Size(0 bytes),
],
memory_index: [
0,
],
},
largest_niche: Some(
Niche {
offset: Size(0 bytes),
@ -91,7 +98,14 @@ error: layout_of((i8) is (i8::MIN..=-2 | 0..)) = Layout {
valid_range: 0..=254,
},
),
fields: Primitive,
fields: Arbitrary {
offsets: [
Size(0 bytes),
],
memory_index: [
0,
],
},
largest_niche: Some(
Niche {
offset: Size(0 bytes),

27
tests/ui/type/pattern_types/range_patterns.stderr
View file

@ -57,7 +57,14 @@ error: layout_of((u32) is 1..) = Layout {
valid_range: 1..=4294967295,
},
),
fields: Primitive,
fields: Arbitrary {
offsets: [
Size(0 bytes),
],
memory_index: [
0,
],
},
largest_niche: Some(
Niche {
offset: Size(0 bytes),
@ -390,7 +397,14 @@ error: layout_of((i8) is -10..=10) = Layout {
valid_range: (..=10) | (246..),
},
),
fields: Primitive,
fields: Arbitrary {
offsets: [
Size(0 bytes),
],
memory_index: [
0,
],
},
largest_niche: Some(
Niche {
offset: Size(0 bytes),
@ -428,7 +442,14 @@ error: layout_of((i8) is i8::MIN..=0) = Layout {
valid_range: (..=0) | (128..),
},
),
fields: Primitive,
fields: Arbitrary {
offsets: [
Size(0 bytes),
],
memory_index: [
0,
],
},
largest_niche: Some(
Niche {
offset: Size(0 bytes),