diff --git a/include/swift/Serialization/ModuleFormat.h b/include/swift/Serialization/ModuleFormat.h
index dbb09fc1368..11fcad9a8c4 100644
--- a/include/swift/Serialization/ModuleFormat.h
+++ b/include/swift/Serialization/ModuleFormat.h
@@ -261,6 +261,8 @@ enum LayoutRequirementKind : uint8_t {
   Trivial = 3,
   RefCountedObject = 4,
   NativeRefCountedObject = 5,
+  Class = 6,
+  NativeClass = 7
 };
 using LayoutRequirementKindField = BCFixed<3>;
 
diff --git a/lib/Serialization/Deserialization.cpp b/lib/Serialization/Deserialization.cpp
index 376e2f1126f..d9d544ac513 100644
--- a/lib/Serialization/Deserialization.cpp
+++ b/lib/Serialization/Deserialization.cpp
@@ -1030,31 +1030,31 @@ void ModuleFile::readGenericRequirements(
         error();
         break;
       }
-      case LayoutRequirementKind::NativeRefCountedObject: {
+      case LayoutRequirementKind::NativeRefCountedObject:
         kind = LayoutConstraintKind::NativeRefCountedObject;
         break;
-      }
-      case LayoutRequirementKind::RefCountedObject: {
+      case LayoutRequirementKind::RefCountedObject:
         kind = LayoutConstraintKind::RefCountedObject;
         break;
-      }
-      case LayoutRequirementKind::Trivial: {
+      case LayoutRequirementKind::Trivial:
         kind = LayoutConstraintKind::Trivial;
         break;
-      }
-      case LayoutRequirementKind::TrivialOfExactSize: {
+      case LayoutRequirementKind::TrivialOfExactSize:
         kind = LayoutConstraintKind::TrivialOfExactSize;
         break;
-      }
-      case LayoutRequirementKind::TrivialOfAtMostSize: {
+      case LayoutRequirementKind::TrivialOfAtMostSize:
         kind = LayoutConstraintKind::TrivialOfAtMostSize;
         break;
-      }
-      case LayoutRequirementKind::UnknownLayout: {
+      case LayoutRequirementKind::Class:
+        kind = LayoutConstraintKind::Class;
+        break;
+      case LayoutRequirementKind::NativeClass:
+        kind = LayoutConstraintKind::NativeClass;
+        break;
+      case LayoutRequirementKind::UnknownLayout:
         kind = LayoutConstraintKind::UnknownLayout;
         break;
       }
-      }
 
       ASTContext &ctx = getContext();
       if (kind != LayoutConstraintKind::TrivialOfAtMostSize &&
diff --git a/lib/Serialization/Serialization.cpp b/lib/Serialization/Serialization.cpp
index 2a16ac985ce..18b4278e75d 100644
--- a/lib/Serialization/Serialization.cpp
+++ b/lib/Serialization/Serialization.cpp
@@ -1122,8 +1122,35 @@ void Serializer::writeGenericRequirements(ArrayRef<Requirement> requirements,
         size = layout->getTrivialSizeInBits();
         alignment = layout->getAlignment();
       }
+      LayoutRequirementKind rawKind = LayoutRequirementKind::UnknownLayout;
+      switch (layout->getKind()) {
+      case LayoutConstraintKind::NativeRefCountedObject:
+        rawKind = LayoutRequirementKind::NativeRefCountedObject;
+        break;
+      case LayoutConstraintKind::RefCountedObject:
+        rawKind = LayoutRequirementKind::RefCountedObject;
+        break;
+      case LayoutConstraintKind::Trivial:
+        rawKind = LayoutRequirementKind::Trivial;
+        break;
+      case LayoutConstraintKind::TrivialOfExactSize:
+        rawKind = LayoutRequirementKind::TrivialOfExactSize;
+        break;
+      case LayoutConstraintKind::TrivialOfAtMostSize:
+        rawKind = LayoutRequirementKind::TrivialOfAtMostSize;
+        break;
+      case LayoutConstraintKind::Class:
+        rawKind = LayoutRequirementKind::Class;
+        break;
+      case LayoutConstraintKind::NativeClass:
+        rawKind = LayoutRequirementKind::NativeClass;
+        break;
+      case LayoutConstraintKind::UnknownLayout:
+        rawKind = LayoutRequirementKind::UnknownLayout;
+        break;
+      }
       LayoutRequirementLayout::emitRecord(
-          Out, ScratchRecord, layoutReqAbbrCode, (unsigned)layout->getKind(),
+          Out, ScratchRecord, layoutReqAbbrCode, rawKind,
           addTypeRef(req.getFirstType()), size, alignment);
     }
   }