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Merge pull request #70457 from slavapestov/parameter-pack-open-type

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Fix openType() handling of parameter packs
This commit is contained in:
Slava Pestov
2024-01-10 13:41:08 -05:00
committed by GitHub
parent 25789fd767 bc7044e944
commit 597fb216cb
10 changed files with 205 additions and 80 deletions
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40
lib/Sema/ConstraintSystem.cpp
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@@ -969,25 +969,7 @@ Type ConstraintSystem::openUnboundGenericType(GenericTypeDecl *decl,
result = DC->mapTypeIntoContext(result);
}
return result.transform([&](Type type) -> Type {
// Although generic parameters are declared with just `each`
// their interface types introduce a pack expansion which
// means that the solver has to extact generic argument type
// variable from Pack{repeat ...} and drop that structure to
// make sure that generic argument gets inferred to a pack type.
if (auto *packTy = type->getAs<PackType>()) {
assert(packTy->getNumElements() == 1);
auto *expansion = packTy->getElementType(0)->castTo<PackExpansionType>();
auto *typeVar = expansion->getPatternType()->castTo<TypeVariableType>();
assert(typeVar->getImpl().getGenericParameter() &&
typeVar->getImpl().canBindToPack());
return typeVar;
}
if (auto *expansion = dyn_cast<PackExpansionType>(type.getPointer()))
return openPackExpansionType(expansion, replacements, locator);
return type;
});
return result;
}
static void checkNestedTypeConstraints(ConstraintSystem &cs, Type type,
@@ -1136,18 +1118,6 @@ Type ConstraintSystem::openType(Type type, OpenedTypeMap &replacements,
}
}
// While opening variadic generic types that appear in other types
// we need to extract generic parameter from Pack{repeat ...} structure
// that gets introduced by the interface type, see
// \c openUnboundGenericType for more details.
if (auto *packTy = type->getAs<PackType>()) {
if (auto expansionTy = packTy->unwrapSingletonPackExpansion()) {
auto patternTy = expansionTy->getPatternType();
if (patternTy->isTypeParameter())
return openType(patternTy, replacements, locator);
}
}
if (auto *expansion = type->getAs<PackExpansionType>()) {
return openPackExpansionType(expansion, replacements, locator);
}
@@ -4143,6 +4113,14 @@ struct TypeSimplifier {
auto countType = expansion->getCountType().transform(
TypeSimplifier(CS, GetFixedTypeFn));
if (!countType->is<PackType>() &&
!countType->is<PackArchetypeType>()) {
SmallVector<Type, 2> rootParameterPacks;
countType->getTypeParameterPacks(rootParameterPacks);
if (!rootParameterPacks.empty())
countType = rootParameterPacks[0];
}
// If both pattern and count are resolves, let's just return
// the pattern type for `transformWithPosition` to take care
// of the rest.