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Make 'T.self is U.Type' work.

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Fix up all of type-checking, SILGen, IRGen, and the runtime to support checked casts of metatypes. <rdar://problem/16847453>

Swift SVN r17719
This commit is contained in:
Joe Groff
2014-05-08 22:55:14 +00:00
parent f18dbbe9e8
commit 1dce36edd2
11 changed files with 320 additions and 5 deletions
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23
lib/Sema/CSSimplify.cpp
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@@ -1985,6 +1985,26 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyConformsToConstraint(
/// This routine does not attempt to check whether the cast can actually
/// succeed; that's the caller's responsibility.
static CheckedCastKind getCheckedCastKind(Type fromType, Type toType) {
// Peel off optionals metatypes from the types, because we might cast through
// them.
while (auto toValueType = toType->getAnyOptionalObjectType()) {
toType = toValueType;
}
while (auto fromValueType = fromType->getAnyOptionalObjectType()) {
fromType = fromValueType;
}
// Peel off metatypes, since if we can cast two types, we can cast their
// metatypes.
while (auto toMetatype = toType->getAs<MetatypeType>()) {
auto fromMetatype = fromType->getAs<MetatypeType>();
if (!fromMetatype)
break;
toType = toMetatype->getInstanceType();
fromType = fromMetatype->getInstanceType();
}
// Classify the from/to types.
bool toArchetype = toType->is<ArchetypeType>();
bool fromArchetype = fromType->is<ArchetypeType>();
@@ -2062,7 +2082,8 @@ ConstraintSystem::simplifyCheckedCastConstraint(
if (typeVar2)
return SolutionKind::Unsolved;
switch (getCheckedCastKind(fromType, toType)) {
auto kind = getCheckedCastKind(fromType, toType);
switch (kind) {
case CheckedCastKind::ArchetypeToArchetype:
case CheckedCastKind::ConcreteToUnrelatedExistential:
case CheckedCastKind::ExistentialToArchetype: