diff options
Diffstat (limited to 'compiler/rustc_pattern_analysis/src/cx.rs')
| -rw-r--r-- | compiler/rustc_pattern_analysis/src/cx.rs | 73 |
1 files changed, 41 insertions, 32 deletions
diff --git a/compiler/rustc_pattern_analysis/src/cx.rs b/compiler/rustc_pattern_analysis/src/cx.rs index 8a4f39a1f4a..81c836b878e 100644 --- a/compiler/rustc_pattern_analysis/src/cx.rs +++ b/compiler/rustc_pattern_analysis/src/cx.rs @@ -105,7 +105,7 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { ) -> VariantIdx { match *ctor { Variant(idx) => idx, - Single => { + Struct | UnionField => { assert!(!adt.is_enum()); FIRST_VARIANT } @@ -123,9 +123,8 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { ) -> &'p [DeconstructedPat<'p, 'tcx>] { let cx = self; match ctor { - Single | Variant(_) => match ty.kind() { + Struct | Variant(_) | UnionField => match ty.kind() { ty::Tuple(fs) => cx.alloc_wildcard_slice(fs.iter()), - ty::Ref(_, rty, _) => cx.alloc_wildcard_slice(once(*rty)), ty::Adt(adt, args) => { if adt.is_box() { // The only legal patterns of type `Box` (outside `std`) are `_` and box @@ -138,7 +137,11 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { cx.alloc_wildcard_slice(tys) } } - _ => bug!("Unexpected type for `Single` constructor: {:?}", ty), + _ => bug!("Unexpected type for constructor `{ctor:?}`: {ty:?}"), + }, + Ref => match ty.kind() { + ty::Ref(_, rty, _) => cx.alloc_wildcard_slice(once(*rty)), + _ => bug!("Unexpected type for `Ref` constructor: {ty:?}"), }, Slice(slice) => match *ty.kind() { ty::Slice(ty) | ty::Array(ty, _) => { @@ -167,9 +170,8 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { /// `Fields::wildcards`. pub(crate) fn ctor_arity(&self, ctor: &Constructor<'tcx>, ty: Ty<'tcx>) -> usize { match ctor { - Single | Variant(_) => match ty.kind() { + Struct | Variant(_) | UnionField => match ty.kind() { ty::Tuple(fs) => fs.len(), - ty::Ref(..) => 1, ty::Adt(adt, ..) => { if adt.is_box() { // The only legal patterns of type `Box` (outside `std`) are `_` and box @@ -181,8 +183,9 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { self.list_variant_nonhidden_fields(ty, variant).count() } } - _ => bug!("Unexpected type for `Single` constructor: {:?}", ty), + _ => bug!("Unexpected type for constructor `{ctor:?}`: {ty:?}"), }, + Ref => 1, Slice(slice) => slice.arity(), Bool(..) | IntRange(..) @@ -298,9 +301,9 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { ConstructorSet::Variants { variants, non_exhaustive: is_declared_nonexhaustive } } } - ty::Adt(..) | ty::Tuple(..) | ty::Ref(..) => { - ConstructorSet::Single { empty: cx.is_uninhabited(ty) } - } + ty::Adt(def, _) if def.is_union() => ConstructorSet::Union, + ty::Adt(..) | ty::Tuple(..) => ConstructorSet::Struct { empty: cx.is_uninhabited(ty) }, + ty::Ref(..) => ConstructorSet::Ref, ty::Never => ConstructorSet::NoConstructors, // This type is one for which we cannot list constructors, like `str` or `f64`. // FIXME(Nadrieril): which of these are actually allowed? @@ -359,13 +362,18 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { fields = &[]; } PatKind::Deref { subpattern } => { - ctor = Single; fields = singleton(self.lower_pat(subpattern)); + ctor = match pat.ty.kind() { + // This is a box pattern. + ty::Adt(adt, ..) if adt.is_box() => Struct, + ty::Ref(..) => Ref, + _ => bug!("pattern has unexpected type: pat: {:?}, ty: {:?}", pat, pat.ty), + }; } PatKind::Leaf { subpatterns } | PatKind::Variant { subpatterns, .. } => { match pat.ty.kind() { ty::Tuple(fs) => { - ctor = Single; + ctor = Struct; let mut wilds: SmallVec<[_; 2]> = fs.iter().map(|ty| DeconstructedPat::wildcard(ty, pat.span)).collect(); for pat in subpatterns { @@ -380,7 +388,7 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { // _)` or a box pattern. As a hack to avoid an ICE with the former, we // ignore other fields than the first one. This will trigger an error later // anyway. - // See https://github.com/rust-lang/rust/issues/82772 , + // See https://github.com/rust-lang/rust/issues/82772, // explanation: https://github.com/rust-lang/rust/pull/82789#issuecomment-796921977 // The problem is that we can't know from the type whether we'll match // normally or through box-patterns. We'll have to figure out a proper @@ -392,12 +400,13 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { } else { DeconstructedPat::wildcard(args.type_at(0), pat.span) }; - ctor = Single; + ctor = Struct; fields = singleton(pat); } ty::Adt(adt, _) => { ctor = match pat.kind { - PatKind::Leaf { .. } => Single, + PatKind::Leaf { .. } if adt.is_union() => UnionField, + PatKind::Leaf { .. } => Struct, PatKind::Variant { variant_index, .. } => Variant(variant_index), _ => bug!(), }; @@ -477,11 +486,11 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { // with other `Deref` patterns. This could have been done in `const_to_pat`, // but that causes issues with the rest of the matching code. // So here, the constructor for a `"foo"` pattern is `&` (represented by - // `Single`), and has one field. That field has constructor `Str(value)` and no - // fields. + // `Ref`), and has one field. That field has constructor `Str(value)` and no + // subfields. // Note: `t` is `str`, not `&str`. let subpattern = DeconstructedPat::new(Str(*value), &[], *t, pat.span); - ctor = Single; + ctor = Ref; fields = singleton(subpattern) } // All constants that can be structurally matched have already been expanded @@ -657,7 +666,7 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { let kind = match pat.ctor() { Bool(b) => PatKind::Constant { value: mir::Const::from_bool(cx.tcx, *b) }, IntRange(range) => return self.hoist_pat_range(range, pat.ty()), - Single | Variant(_) => match pat.ty().kind() { + Struct | Variant(_) | UnionField => match pat.ty().kind() { ty::Tuple(..) => PatKind::Leaf { subpatterns: subpatterns .enumerate() @@ -686,13 +695,13 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { PatKind::Leaf { 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 - // ignore this issue. - ty::Ref(..) => PatKind::Deref { subpattern: subpatterns.next().unwrap() }, _ => bug!("unexpected ctor for type {:?} {:?}", pat.ctor(), pat.ty()), }, + // 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 + // ignore this issue. + Ref => PatKind::Deref { subpattern: subpatterns.next().unwrap() }, Slice(slice) => { match slice.kind { SliceKind::FixedLen(_) => PatKind::Slice { @@ -758,7 +767,7 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { let mut start_or_comma = || start_or_continue(", "); match pat.ctor() { - Single | Variant(_) => match pat.ty().kind() { + Struct | Variant(_) | UnionField => match pat.ty().kind() { ty::Adt(def, _) if def.is_box() => { // Without `box_patterns`, the only legal pattern of type `Box` is `_` (outside // of `std`). So this branch is only reachable when the feature is enabled and @@ -789,15 +798,15 @@ impl<'p, 'tcx> MatchCheckCtxt<'p, 'tcx> { } write!(f, ")") } - // Note: given the expansion of `&str` patterns done in `expand_pattern`, we should - // be careful to detect strings here. However a string literal pattern will never - // be reported as a non-exhaustiveness witness, so we can ignore this issue. - ty::Ref(_, _, mutbl) => { - let subpattern = pat.iter_fields().next().unwrap(); - write!(f, "&{}{:?}", mutbl.prefix_str(), subpattern) - } _ => write!(f, "_"), }, + // Note: given the expansion of `&str` patterns done in `expand_pattern`, we should + // be careful to detect strings here. However a string literal pattern will never + // be reported as a non-exhaustiveness witness, so we can ignore this issue. + Ref => { + let subpattern = pat.iter_fields().next().unwrap(); + write!(f, "&{:?}", subpattern) + } Slice(slice) => { let mut subpatterns = pat.iter_fields(); write!(f, "[")?; |