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NadrierilNadrieril
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Inline constructor_sub_pattern_tys
It was only used at a single location
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-67
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‎src/librustc_mir/hair/pattern/_match.rs

+63-67
Original file line numberDiff line numberDiff line change
@@ -779,8 +779,67 @@ impl<'tcx> Constructor<'tcx> {
779779
&self,
780780
cx: &MatchCheckCtxt<'a, 'tcx>,
781781
ty: Ty<'tcx>,
782-
) -> impl Iterator<Item = Pat<'tcx>> + DoubleEndedIterator {
783-
constructor_sub_pattern_tys(cx, self, ty).into_iter().map(Pat::wildcard_from_ty)
782+
) -> Vec<Pat<'tcx>> {
783+
debug!("wildcard_subpatterns({:#?}, {:?})", self, ty);
784+
match ty.kind {
785+
ty::Tuple(ref fs) => {
786+
fs.into_iter().map(|t| t.expect_ty()).map(Pat::wildcard_from_ty).collect()
787+
}
788+
ty::Slice(ty) | ty::Array(ty, _) => match *self {
789+
FixedLenSlice(length) => (0..length).map(|_| Pat::wildcard_from_ty(ty)).collect(),
790+
VarLenSlice(prefix, suffix) => {
791+
(0..prefix + suffix).map(|_| Pat::wildcard_from_ty(ty)).collect()
792+
}
793+
ConstantValue(..) => vec![],
794+
_ => bug!("bad slice pattern {:?} {:?}", self, ty),
795+
},
796+
ty::Ref(_, rty, _) => vec![Pat::wildcard_from_ty(rty)],
797+
ty::Adt(adt, substs) => {
798+
if adt.is_box() {
799+
// Use T as the sub pattern type of Box<T>.
800+
vec![Pat::wildcard_from_ty(substs.type_at(0))]
801+
} else {
802+
let variant = &adt.variants[self.variant_index_for_adt(cx, adt)];
803+
let is_non_exhaustive =
804+
variant.is_field_list_non_exhaustive() && !cx.is_local(ty);
805+
variant
806+
.fields
807+
.iter()
808+
.map(|field| {
809+
let is_visible =
810+
adt.is_enum() || field.vis.is_accessible_from(cx.module, cx.tcx);
811+
let is_uninhabited = cx.is_uninhabited(field.ty(cx.tcx, substs));
812+
match (is_visible, is_non_exhaustive, is_uninhabited) {
813+
// Treat all uninhabited types in non-exhaustive variants as `TyErr`.
814+
(_, true, true) => cx.tcx.types.err,
815+
// Treat all non-visible fields as `TyErr`. They can't appear in any
816+
// other pattern from this match (because they are private), so their
817+
// type does not matter - but we don't want to know they are
818+
// uninhabited.
819+
(false, ..) => cx.tcx.types.err,
820+
(true, ..) => {
821+
let ty = field.ty(cx.tcx, substs);
822+
match ty.kind {
823+
// If the field type returned is an array of an unknown size
824+
// return an TyErr.
825+
ty::Array(_, len)
826+
if len
827+
.try_eval_usize(cx.tcx, cx.param_env)
828+
.is_none() =>
829+
{
830+
cx.tcx.types.err
831+
}
832+
_ => ty,
833+
}
834+
}
835+
}
836+
})
837+
.map(Pat::wildcard_from_ty)
838+
.collect()
839+
}
840+
}
841+
_ => vec![],
842+
}
784843
}
785844

786845
/// This computes the arity of a constructor. The arity of a constructor
@@ -880,7 +939,7 @@ impl<'tcx> Constructor<'tcx> {
880939

881940
/// Like `apply`, but where all the subpatterns are wildcards `_`.
882941
fn apply_wildcards<'a>(&self, cx: &MatchCheckCtxt<'a, 'tcx>, ty: Ty<'tcx>) -> Pat<'tcx> {
883-
let subpatterns = self.wildcard_subpatterns(cx, ty).rev();
942+
let subpatterns = self.wildcard_subpatterns(cx, ty).into_iter().rev();
884943
self.apply(cx, ty, subpatterns)
885944
}
886945
}
@@ -1659,7 +1718,7 @@ fn is_useful_specialized<'p, 'a, 'tcx>(
16591718
) -> Usefulness<'tcx> {
16601719
debug!("is_useful_specialized({:#?}, {:#?}, {:?})", v, ctor, lty);
16611720

1662-
let ctor_wild_subpatterns_owned: Vec<_> = ctor.wildcard_subpatterns(cx, lty).collect();
1721+
let ctor_wild_subpatterns_owned: Vec<_> = ctor.wildcard_subpatterns(cx, lty);
16631722
let ctor_wild_subpatterns: Vec<_> = ctor_wild_subpatterns_owned.iter().collect();
16641723
let matrix = matrix.specialize_constructor(cx, &ctor, &ctor_wild_subpatterns);
16651724
v.specialize_constructor(cx, &ctor, &ctor_wild_subpatterns)
@@ -1709,69 +1768,6 @@ fn pat_constructor<'tcx>(
17091768
}
17101769
}
17111770

1712-
/// This computes the types of the sub patterns that a constructor should be
1713-
/// expanded to.
1714-
///
1715-
/// For instance, a tuple pattern (43u32, 'a') has sub pattern types [u32, char].
1716-
fn constructor_sub_pattern_tys<'a, 'tcx>(
1717-
cx: &MatchCheckCtxt<'a, 'tcx>,
1718-
ctor: &Constructor<'tcx>,
1719-
ty: Ty<'tcx>,
1720-
) -> Vec<Ty<'tcx>> {
1721-
debug!("constructor_sub_pattern_tys({:#?}, {:?})", ctor, ty);
1722-
match ty.kind {
1723-
ty::Tuple(ref fs) => fs.into_iter().map(|t| t.expect_ty()).collect(),
1724-
ty::Slice(ty) | ty::Array(ty, _) => match *ctor {
1725-
FixedLenSlice(length) => (0..length).map(|_| ty).collect(),
1726-
VarLenSlice(prefix, suffix) => (0..prefix + suffix).map(|_| ty).collect(),
1727-
ConstantValue(..) => vec![],
1728-
_ => bug!("bad slice pattern {:?} {:?}", ctor, ty),
1729-
},
1730-
ty::Ref(_, rty, _) => vec![rty],
1731-
ty::Adt(adt, substs) => {
1732-
if adt.is_box() {
1733-
// Use T as the sub pattern type of Box<T>.
1734-
vec![substs.type_at(0)]
1735-
} else {
1736-
let variant = &adt.variants[ctor.variant_index_for_adt(cx, adt)];
1737-
let is_non_exhaustive = variant.is_field_list_non_exhaustive() && !cx.is_local(ty);
1738-
variant
1739-
.fields
1740-
.iter()
1741-
.map(|field| {
1742-
let is_visible =
1743-
adt.is_enum() || field.vis.is_accessible_from(cx.module, cx.tcx);
1744-
let is_uninhabited = cx.is_uninhabited(field.ty(cx.tcx, substs));
1745-
match (is_visible, is_non_exhaustive, is_uninhabited) {
1746-
// Treat all uninhabited types in non-exhaustive variants as `TyErr`.
1747-
(_, true, true) => cx.tcx.types.err,
1748-
// Treat all non-visible fields as `TyErr`. They can't appear in any
1749-
// other pattern from this match (because they are private), so their
1750-
// type does not matter - but we don't want to know they are
1751-
// uninhabited.
1752-
(false, ..) => cx.tcx.types.err,
1753-
(true, ..) => {
1754-
let ty = field.ty(cx.tcx, substs);
1755-
match ty.kind {
1756-
// If the field type returned is an array of an unknown size
1757-
// return an TyErr.
1758-
ty::Array(_, len)
1759-
if len.try_eval_usize(cx.tcx, cx.param_env).is_none() =>
1760-
{
1761-
cx.tcx.types.err
1762-
}
1763-
_ => ty,
1764-
}
1765-
}
1766-
}
1767-
})
1768-
.collect()
1769-
}
1770-
}
1771-
_ => vec![],
1772-
}
1773-
}
1774-
17751771
// checks whether a constant is equal to a user-written slice pattern. Only supports byte slices,
17761772
// meaning all other types will compare unequal and thus equal patterns often do not cause the
17771773
// second pattern to lint about unreachable match arms.

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