diff --git a/include/clang/AST/DeclObjC.h b/include/clang/AST/DeclObjC.h
index 4229fd3..42dd5a3 100644
--- a/include/clang/AST/DeclObjC.h
+++ b/include/clang/AST/DeclObjC.h
@@ -940,7 +940,8 @@
   ObjCInterfaceDecl *lookupInheritedClass(const IdentifierInfo *ICName);
 
   /// \brief Lookup a method in the classes implementation hierarchy.
-  ObjCMethodDecl *lookupPrivateMethod(const Selector &Sel, bool Instance=true);
+  ObjCMethodDecl *lookupPrivateMethod(const Selector &Sel,
+                                      bool Instance=true) const;
 
   ObjCMethodDecl *lookupPrivateClassMethod(const Selector &Sel) {
     return lookupPrivateMethod(Sel, false);
diff --git a/lib/AST/DeclObjC.cpp b/lib/AST/DeclObjC.cpp
index cbd1524..4d48ad8 100644
--- a/lib/AST/DeclObjC.cpp
+++ b/lib/AST/DeclObjC.cpp
@@ -368,7 +368,7 @@
 // Returns 0 if no method is found.
 ObjCMethodDecl *ObjCInterfaceDecl::lookupPrivateMethod(
                                    const Selector &Sel,
-                                   bool Instance) {
+                                   bool Instance) const {
   // FIXME: Should make sure no callers ever do this.
   if (!hasDefinition())
     return 0;