Distributed: Remove flattenDistributedSerializationTypeToRequiredProtocols()

Author: slavapestov

include/swift/AST/DistributedDecl.h

@@ -91,12 +91,6 @@ llvm::SmallPtrSet<ProtocolDecl *, 2>
 getDistributedSerializationRequirementProtocols(
     NominalTypeDecl *decl, ProtocolDecl* protocol);
 
-/// Desugar and flatten the `SerializationRequirement` type into a set of
-/// specific protocol declarations.
-llvm::SmallPtrSet<ProtocolDecl *, 2>
-flattenDistributedSerializationTypeToRequiredProtocols(
-    TypeBase *serializationRequirement);
-
 /// Check if the `allRequirements` represent *exactly* the
 /// `Encodable & Decodable` (also known as `Codable`) requirement.
 ///

lib/AST/DistributedDecl.cpp

@@ -340,47 +340,19 @@ swift::getDistributedSerializationRequirements(
   if (existentialRequirementTy->isAny())
     return true; // we're done here, any means there are no requirements
 
-  ExistentialType *serialReqType = existentialRequirementTy
-                                       ->getAs<ExistentialType>();
+  auto *serialReqType = existentialRequirementTy->getAs<ExistentialType>();
   if (!serialReqType || serialReqType->hasError()) {
     return false;
   }
 
-  auto desugaredTy = serialReqType->getConstraintType();
-  auto flattenedRequirements =
-      flattenDistributedSerializationTypeToRequiredProtocols(
-          desugaredTy.getPointer());
-  for (auto p : flattenedRequirements) {
+  auto layout = serialReqType->getExistentialLayout();
+  for (auto p : layout.getProtocols()) {
     requirementProtos.insert(p);
   }
 
   return true;
 }
 
-llvm::SmallPtrSet<ProtocolDecl *, 2>
-swift::flattenDistributedSerializationTypeToRequiredProtocols(
-    TypeBase *serializationRequirement) {
-  llvm::SmallPtrSet<ProtocolDecl *, 2> serializationReqs;
-  if (auto composition =
-          serializationRequirement->getAs<ProtocolCompositionType>()) {
-    for (auto member : composition->getMembers()) {
-      if (auto comp = member->getAs<ProtocolCompositionType>()) {
-        for (auto protocol :
-             flattenDistributedSerializationTypeToRequiredProtocols(comp)) {
-          serializationReqs.insert(protocol);
-        }
-      } else if (auto *protocol = member->getAs<ProtocolType>()) {
-        serializationReqs.insert(protocol->getDecl());
-      }
-    }
-  } else {
-    auto protocol = serializationRequirement->castTo<ProtocolType>()->getDecl();
-    serializationReqs.insert(protocol);
-  }
-
-  return serializationReqs;
-}
-
 bool swift::checkDistributedSerializationRequirementIsExactlyCodable(
     ASTContext &C,
     const llvm::SmallPtrSetImpl<ProtocolDecl *> &allRequirements) {
@@ -1260,19 +1232,9 @@ swift::extractDistributedSerializationRequirements(
     if (auto dependentMemberType =
             req.getFirstType()->castTo<DependentMemberType>()) {
       if (dependentMemberType->getAssocType() == daSerializationReqAssocType) {
-        auto requirementProto = req.getSecondType();
-        if (auto proto = dyn_cast_or_null<ProtocolDecl>(
-                requirementProto->getAnyNominal())) {
-          serializationReqs.insert(proto);
-        } else {
-          auto serialReqType = requirementProto->castTo<ExistentialType>()
-                                   ->getConstraintType();
-          auto flattenedRequirements =
-              flattenDistributedSerializationTypeToRequiredProtocols(
-                  serialReqType.getPointer());
-          for (auto p : flattenedRequirements) {
-            serializationReqs.insert(p);
-          }
+        auto layout = req.getSecondType()->getExistentialLayout();
+        for (auto p : layout.getProtocols()) {
+          serializationReqs.insert(p);
         }
       }
     }

lib/Sema/TypeCheckDistributed.cpp

@@ -507,8 +507,8 @@ bool CheckDistributedFunctionRequest::evaluate(
   } else if (isa<ProtocolDecl>(DC)) {
     if (auto seqReqTy =
         getConcreteReplacementForMemberSerializationRequirement(func)) {
-      auto seqReqTyDes = seqReqTy->castTo<ExistentialType>()->getConstraintType()->getDesugaredType();
-      for (auto req : flattenDistributedSerializationTypeToRequiredProtocols(seqReqTyDes)) {
+      auto layout = seqReqTy->getExistentialLayout();
+      for (auto req : layout.getProtocols()) {
         serializationRequirements.insert(req);
       }
     }
@@ -759,11 +759,13 @@ swift::getDistributedSerializationRequirementProtocols(
     return {};
   }
 
-  auto serialReqType =
-      ty->castTo<ExistentialType>()->getConstraintType()->getDesugaredType();
-
   // TODO(distributed): check what happens with Any
-  return flattenDistributedSerializationTypeToRequiredProtocols(serialReqType);
+  auto layout = ty->getExistentialLayout();
+  llvm::SmallPtrSet<ProtocolDecl *, 2> result;
+  for (auto p : layout.getProtocols()) {
+    result.insert(p);
+  }
+  return result;
 }
 
 ConstructorDecl*