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Simplify hoisting of struct-like patterns

This commit is contained in:
Zalathar 2024-08-02 20:28:56 +10:00
parent a5ed6fb646
commit c764bea0c3
1 changed files with 16 additions and 23 deletions
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39
compiler/rustc_pattern_analysis/src/rustc.rs
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@ -838,31 +838,24 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
// of type `Box` is to use a `box` pattern via #[feature(box_patterns)].
PatKind::Box { subpattern: hoist(&pat.fields[0]) }
}
Struct | Variant(_) | UnionField => match pat.ty().kind() {
ty::Tuple(..) => PatKind::StructLike {
enum_info: EnumInfo::NotEnum,
subpatterns: subpatterns
.enumerate()
.map(|(i, pattern)| FieldPat { field: FieldIdx::new(i), pattern })
.collect(),
},
&ty::Adt(adt_def, _) => {
let variant_index = RustcPatCtxt::variant_index_for_adt(&pat.ctor(), adt_def);
let subpatterns = subpatterns
.enumerate()
.map(|(i, pattern)| FieldPat { field: FieldIdx::new(i), pattern })
.collect();
Struct | Variant(_) | UnionField => {
let enum_info = match *pat.ty().kind() {
ty::Adt(adt_def, _) if adt_def.is_enum() => EnumInfo::Enum {
adt_def,
variant_index: RustcPatCtxt::variant_index_for_adt(pat.ctor(), adt_def),
},
ty::Adt(..) | ty::Tuple(..) => EnumInfo::NotEnum,
_ => bug!("unexpected ctor for type {:?} {:?}", pat.ctor(), *pat.ty()),
};
let enum_info = if adt_def.is_enum() {
EnumInfo::Enum { adt_def, variant_index }
} else {
EnumInfo::NotEnum
};
let subpatterns = pat
.iter_fields()
.enumerate()
.map(|(i, pat)| FieldPat { field: FieldIdx::new(i), pattern: hoist(pat) })
.collect::<Vec<_>>();
PatKind::StructLike { enum_info, subpatterns }
}
_ => bug!("unexpected ctor for type {:?} {:?}", pat.ctor(), *pat.ty()),
},
PatKind::StructLike { enum_info, subpatterns }
}
// Note: given the expansion of `&str` patterns done in `expand_pattern`, we should
// be careful to reconstruct the correct constant pattern here. However a string
// literal pattern will never be reported as a non-exhaustiveness witness, so we