[Serialization] Serialize hasMissingDesignatedInitializers

Since this is going to be something modules tell clients, rather than something clients discover about modules, serialize it.

lib/Serialization/Deserialization.cpp

@@ -3416,6 +3416,7 @@ public:
     DeclContextID contextID;
     bool isImplicit, isObjC;
     bool inheritsSuperclassInitializers;
+    bool hasMissingDesignatedInits;
     GenericSignatureID genericSigID;
     TypeID superclassID;
     uint8_t rawAccessLevel;
@@ -3424,6 +3425,7 @@ public:
     decls_block::ClassLayout::readRecord(scratch, nameID, contextID,
                                          isImplicit, isObjC,
                                          inheritsSuperclassInitializers,
+                                         hasMissingDesignatedInits,
                                          genericSigID, superclassID,
                                          rawAccessLevel, numConformances,
                                          numInheritedTypes,
@@ -3466,6 +3468,8 @@ public:
     theClass->setSuperclass(MF.getType(superclassID));
     ctx.evaluator.cacheOutput(InheritsSuperclassInitializersRequest{theClass},
                               std::move(inheritsSuperclassInitializers));
+    ctx.evaluator.cacheOutput(HasMissingDesignatedInitializersRequest{theClass},
+                              std::move(hasMissingDesignatedInits));
 
     handleInherited(theClass,
                     rawInheritedAndDependencyIDs.slice(0, numInheritedTypes));
@@ -5390,7 +5394,8 @@ Decl *handleErrorAndSupplyMissingClassMember(ASTContext &context,
   Decl *suppliedMissingMember = nullptr;
   auto handleMissingClassMember = [&](const DeclDeserializationError &error) {
     if (error.isDesignatedInitializer())
-      containingClass->setHasMissingDesignatedInitializers();
+      context.evaluator.cacheOutput(
+          HasMissingDesignatedInitializersRequest{containingClass}, true);
     if (error.getNumberOfVTableEntries() > 0)
       containingClass->setHasMissingVTableEntries();
 

lib/Serialization/ModuleFormat.h

@@ -55,7 +55,7 @@ const uint16_t SWIFTMODULE_VERSION_MAJOR = 0;
 /// describe what change you made. The content of this comment isn't important;
 /// it just ensures a conflict if two people change the module format.
 /// Don't worry about adhering to the 80-column limit for this line.
-const uint16_t SWIFTMODULE_VERSION_MINOR = 531; // function parameter noDerivative
+const uint16_t SWIFTMODULE_VERSION_MINOR = 532; // @_hasMissingDesignatedInitializers
 
 /// A standard hash seed used for all string hashes in a serialized module.
 ///
@@ -1114,6 +1114,7 @@ namespace decls_block {
     BCFixed<1>,             // implicit?
     BCFixed<1>,             // explicitly objc?
     BCFixed<1>,             // inherits convenience initializers from its superclass?
+    BCFixed<1>,             // has missing designated initializers?
     GenericSignatureIDField, // generic environment
     TypeIDField,            // superclass
     AccessLevelField,       // access level

lib/Serialization/Serialization.cpp

@@ -3139,9 +3139,7 @@ public:
     uint8_t rawAccessLevel =
       getRawStableAccessLevel(theClass->getFormalAccess());
 
-    bool inheritsSuperclassInitializers =
-        const_cast<ClassDecl *>(theClass)->
-          inheritsSuperclassInitializers();
+    auto mutableClass = const_cast<ClassDecl *>(theClass);
 
     unsigned abbrCode = S.DeclTypeAbbrCodes[ClassLayout::Code];
     ClassLayout::emitRecord(S.Out, S.ScratchRecord, abbrCode,
@@ -3149,7 +3147,8 @@ public:
                             contextID.getOpaqueValue(),
                             theClass->isImplicit(),
                             theClass->isObjC(),
-                            inheritsSuperclassInitializers,
+                            mutableClass->inheritsSuperclassInitializers(),
+                            mutableClass->hasMissingDesignatedInitializers(),
                             S.addGenericSignatureRef(
                                              theClass->getGenericSignature()),
                             S.addTypeRef(theClass->getSuperclass()),