Use ObjCImplDecl in place of ObjCCategoryImplDecl/ObjCImplementationDecl.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@77296 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/DeclObjC.cpp b/lib/AST/DeclObjC.cpp
index e082a41..503bc70 100644
--- a/lib/AST/DeclObjC.cpp
+++ b/lib/AST/DeclObjC.cpp
@@ -286,12 +286,10 @@
     return ID;
   if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(getDeclContext()))
     return CD->getClassInterface();
-  if (ObjCImplementationDecl *IMD = 
-      dyn_cast<ObjCImplementationDecl>(getDeclContext()))
+  if (ObjCImplDecl *IMD = dyn_cast<ObjCImplDecl>(getDeclContext()))
     return IMD->getClassInterface();
-  if (ObjCCategoryImplDecl *CID = 
-      dyn_cast<ObjCCategoryImplDecl>(getDeclContext()))
-    return CID->getClassInterface();
+
+  assert(!isa<ObjCProtocolDecl>(getDeclContext()) && "It's a protocol method");
   assert(false && "unknown method context");
   return 0;
 }