[Sema] Factor out InitializablePropertiesRequest

This serves as the backing request for both InitAccessorPropertiesRequest
and MemberwiseInitPropertiesRequest, ensuring the former does not
care about the init accessor is included in the memberwise initializer.

Author: hamishknight

include/swift/AST/TypeCheckRequests.h

@@ -1949,6 +1949,25 @@ class StoredPropertiesAndMissingMembersRequest :
   bool isCached() const { return true; }
 };
 
+/// Request to obtain a list of properties that can be initalized.
+class InitializablePropertiesRequest
+    : public SimpleRequest<InitializablePropertiesRequest,
+                           ArrayRef<VarDecl *>(NominalTypeDecl *),
+                           RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  // Evaluation.
+  ArrayRef<VarDecl *> evaluate(Evaluator &evaluator,
+                               NominalTypeDecl *decl) const;
+
+public:
+  bool isCached() const { return true; }
+};
+
 /// Request to obtain a list of computed properties with init accesors
 /// in the given nominal type.
 class InitAccessorPropertiesRequest :

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -336,6 +336,8 @@ SWIFT_REQUEST(TypeChecker, StoredPropertiesAndMissingMembersRequest,
               ArrayRef<Decl *>(NominalTypeDecl *), Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, StoredPropertiesRequest,
               ArrayRef<VarDecl *>(NominalTypeDecl *), Cached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, InitializablePropertiesRequest,
+              ArrayRef<VarDecl *>(NominalTypeDecl *), Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, InitAccessorPropertiesRequest,
               ArrayRef<VarDecl *>(NominalTypeDecl *),
               Cached, NoLocationInfo)

lib/Sema/TypeCheckStorage.cpp

@@ -322,11 +322,51 @@ bool HasInitAccessorRequest::evaluate(Evaluator &evaluator,
   return var->getAccessor(AccessorKind::Init);
 }
 
+ArrayRef<VarDecl *>
+InitializablePropertiesRequest::evaluate(Evaluator &evaluator,
+                                         NominalTypeDecl *decl) const {
+  IterableDeclContext *implDecl = decl->getImplementationContext();
+
+  if (!hasStoredProperties(decl, implDecl))
+    return ArrayRef<VarDecl *>();
+
+  SmallVector<VarDecl *, 4> results;
+  computeLoweredProperties(decl, implDecl, LoweredPropertiesReason::Memberwise);
+
+  auto maybeAddProperty = [&](VarDecl *var) {
+    if (!var->getDeclContext()->isTypeContext() || var->isStatic())
+      return;
+
+    if (var->getAttrs().hasAttribute<LazyAttr>() ||
+        var->hasAttachedPropertyWrapper() || var->hasStorage() ||
+        var->hasInitAccessor()) {
+      results.push_back(var);
+    }
+  };
+
+  for (auto *member : decl->getMembers()) {
+    if (auto *var = dyn_cast<VarDecl>(member))
+      maybeAddProperty(var);
+
+    member->visitAuxiliaryDecls([&](Decl *auxDecl) {
+      if (auto auxVar = dyn_cast<VarDecl>(auxDecl))
+        maybeAddProperty(auxVar);
+    });
+  }
+
+  return decl->getASTContext().AllocateCopy(results);
+}
+
 ArrayRef<VarDecl *>
 InitAccessorPropertiesRequest::evaluate(Evaluator &evaluator,
                                         NominalTypeDecl *decl) const {
+  auto initableVars =
+      evaluateOrDefault(evaluator, InitializablePropertiesRequest{decl}, {});
+  if (initableVars.empty())
+    return {};
+
   SmallVector<VarDecl *, 4> results;
-  for (auto var : decl->getMemberwiseInitProperties()) {
+  for (auto *var : initableVars) {
     if (var->hasInitAccessor())
       results.push_back(var);
   }
@@ -336,25 +376,19 @@ InitAccessorPropertiesRequest::evaluate(Evaluator &evaluator,
 
 ArrayRef<VarDecl *>
 MemberwiseInitPropertiesRequest::evaluate(Evaluator &evaluator,
-                                        NominalTypeDecl *decl) const {
-  IterableDeclContext *implDecl = decl->getImplementationContext();
-
-  if (!hasStoredProperties(decl, implDecl))
-    return ArrayRef<VarDecl *>();
-
-  // Make sure we expand what we need to to get all of the properties.
-  computeLoweredProperties(decl, implDecl, LoweredPropertiesReason::Memberwise);
+                                          NominalTypeDecl *decl) const {
+  auto initableVars =
+      evaluateOrDefault(evaluator, InitializablePropertiesRequest{decl}, {});
+  if (initableVars.empty())
+    return {};
 
   SmallVector<VarDecl *, 4> results;
   SmallPtrSet<VarDecl *, 4> subsumedViaInitAccessor;
 
-  auto maybeAddProperty = [&](VarDecl *var) {
+  for (auto *var : initableVars) {
     // We only care about properties that are memberwise initialized.
     if (!var->isMemberwiseInitialized(/*preferDeclaredProperties=*/true))
-      return;
-
-    // Add this property.
-    results.push_back(var);
+      continue;
 
     // If this property has an init accessor, it subsumes all of the stored properties
     // that the accessor initializes. Mark those stored properties as being subsumed; we'll
@@ -364,16 +398,9 @@ MemberwiseInitPropertiesRequest::evaluate(Evaluator &evaluator,
         subsumedViaInitAccessor.insert(subsumed);
       }
     }
-  };
-
-  for (auto *member : decl->getCurrentMembers()) {
-    if (auto *var = dyn_cast<VarDecl>(member))
-      maybeAddProperty(var);
 
-    member->visitAuxiliaryDecls([&](Decl *auxDecl) {
-      if (auto auxVar = dyn_cast<VarDecl>(auxDecl))
-        maybeAddProperty(auxVar);
-    });
+    // Add this property.
+    results.push_back(var);
   }
 
   // If any properties were subsumed via init accessors, drop them from the list.