Type
ProtocolConformanceRef::getTypeWitnessByName(Type type,
ProtocolConformanceRef conformance,
Identifier name,
LazyResolver *resolver) {
// For an archetype, retrieve the nested type with the appropriate
// name. There are no conformance tables.
if (auto archetype = type->getAs<ArchetypeType>()) {
return archetype->getNestedType(name);
}
// Find the named requirement.
AssociatedTypeDecl *assocType = nullptr;
auto members = conformance.getRequirement()->lookupDirect(name);
for (auto member : members) {
assocType = dyn_cast<AssociatedTypeDecl>(member);
if (assocType)
break;
}
// FIXME: Shouldn't this be a hard error?
if (!assocType)
return nullptr;
if (conformance.isAbstract())
return DependentMemberType::get(type, assocType);
auto concrete = conformance.getConcrete();
if (!concrete->hasTypeWitness(assocType, resolver)) {
return nullptr;
}
return concrete->getTypeWitness(assocType, resolver);
}
static void getWitnessMethodSubstitutions(ApplySite AI, SILFunction *F,
ProtocolConformanceRef CRef,
SmallVectorImpl<Substitution> &NewSubs) {
auto &Module = AI.getModule();
auto requirementSig = AI.getOrigCalleeType()->getGenericSignature();
auto witnessThunkSig = F->getLoweredFunctionType()->getGenericSignature();
SubstitutionList origSubs = AI.getSubstitutions();
bool isDefaultWitness =
F->getLoweredFunctionType()->getRepresentation()
== SILFunctionTypeRepresentation::WitnessMethod &&
F->getLoweredFunctionType()->getDefaultWitnessMethodProtocol(
*Module.getSwiftModule())
== CRef.getRequirement();
getWitnessMethodSubstitutions(Module, CRef, requirementSig, witnessThunkSig,
origSubs, isDefaultWitness, NewSubs);
}
static SubstitutionMap
getWitnessMethodSubstitutions(SILModule &Module, ApplySite AI, SILFunction *F,
ProtocolConformanceRef CRef) {
auto witnessFnTy = F->getLoweredFunctionType();
assert(witnessFnTy->getRepresentation() ==
SILFunctionTypeRepresentation::WitnessMethod);
auto requirementSig = AI.getOrigCalleeType()->getGenericSignature();
auto witnessThunkSig = witnessFnTy->getGenericSignature();
SubstitutionMap origSubs = AI.getSubstitutionMap();
auto *mod = Module.getSwiftModule();
bool isDefaultWitness =
(witnessFnTy->getDefaultWitnessMethodProtocol()
== CRef.getRequirement());
auto *classWitness = witnessFnTy->getWitnessMethodClass(*mod);
return getWitnessMethodSubstitutions(
mod, CRef, requirementSig, witnessThunkSig,
origSubs, isDefaultWitness, classWitness);
}