1 files changed, 43 insertions, 5 deletions

diff --git a/clang/lib/Sema/SemaDeclObjC.cpp b/clang/lib/Sema/SemaDeclObjC.cpp
index 8ba3e7acec2..32244e9e195 100644
--- a/clang/lib/Sema/SemaDeclObjC.cpp
+++ b/clang/lib/Sema/SemaDeclObjC.cpp
@@ -3281,11 +3281,45 @@ static bool isAcceptableMethodMismatch(ObjCMethodDecl *chosen,
   return (chosen->getReturnType()->isIntegerType());
 }
 
+/// Return true if the given method is wthin the type bound.
+static bool FilterMethodsByTypeBound(ObjCMethodDecl *Method,
+                                     const ObjCObjectType *TypeBound) {
+  if (!TypeBound)
+    return true;
+
+  if (TypeBound->isObjCId())
+    // FIXME: should we handle the case of bounding to id<A, B> differently?
+    return true;
+
+  auto *BoundInterface = TypeBound->getInterface();
+  assert(BoundInterface && "unexpected object type!");
+
+  // Check if the Method belongs to a protocol. We should allow any method
+  // defined in any protocol, because any subclass could adopt the protocol.
+  auto *MethodProtocol = dyn_cast<ObjCProtocolDecl>(Method->getDeclContext());
+  if (MethodProtocol) {
+    return true;
+  }
+
+  // If the Method belongs to a class, check if it belongs to the class
+  // hierarchy of the class bound.
+  if (ObjCInterfaceDecl *MethodInterface = Method->getClassInterface()) {
+    // We allow methods declared within classes that are part of the hierarchy
+    // of the class bound (superclass of, subclass of, or the same as the class
+    // bound).
+    return MethodInterface == BoundInterface ||
+           MethodInterface->isSuperClassOf(BoundInterface) ||
+           BoundInterface->isSuperClassOf(MethodInterface);
+  }
+  llvm_unreachable("unknow method context");
+}
+
 /// We first select the type of the method: Instance or Factory, then collect
 /// all methods with that type.
 bool Sema::CollectMultipleMethodsInGlobalPool(
     Selector Sel, SmallVectorImpl<ObjCMethodDecl *> &Methods,
-    bool InstanceFirst, bool CheckTheOther) {
+    bool InstanceFirst, bool CheckTheOther,
+    const ObjCObjectType *TypeBound) {
   if (ExternalSource)
     ReadMethodPool(Sel);
 
@@ -3297,8 +3331,10 @@ bool Sema::CollectMultipleMethodsInGlobalPool(
   ObjCMethodList &MethList = InstanceFirst ? Pos->second.first :
                              Pos->second.second;
   for (ObjCMethodList *M = &MethList; M; M = M->getNext())
-    if (M->getMethod() && !M->getMethod()->isHidden())
-      Methods.push_back(M->getMethod());
+    if (M->getMethod() && !M->getMethod()->isHidden()) {
+      if (FilterMethodsByTypeBound(M->getMethod(), TypeBound))
+        Methods.push_back(M->getMethod());
+    }
 
   // Return if we find any method with the desired kind.
   if (!Methods.empty())
@@ -3311,8 +3347,10 @@ bool Sema::CollectMultipleMethodsInGlobalPool(
   ObjCMethodList &MethList2 = InstanceFirst ? Pos->second.second :
                               Pos->second.first;
   for (ObjCMethodList *M = &MethList2; M; M = M->getNext())
-    if (M->getMethod() && !M->getMethod()->isHidden())
-      Methods.push_back(M->getMethod());
+    if (M->getMethod() && !M->getMethod()->isHidden()) {
+      if (FilterMethodsByTypeBound(M->getMethod(), TypeBound))
+        Methods.push_back(M->getMethod());
+    }
 
   return Methods.size() > 1;
 }