Index: cfe/trunk/lib/Tooling/Refactoring/Rename/USRFindingAction.cpp
===================================================================
--- cfe/trunk/lib/Tooling/Refactoring/Rename/USRFindingAction.cpp
+++ cfe/trunk/lib/Tooling/Refactoring/Rename/USRFindingAction.cpp
@@ -102,6 +102,10 @@
 
 private:
   void handleCXXRecordDecl(const CXXRecordDecl *RecordDecl) {
+    if (!RecordDecl->getDefinition()) {
+      USRSet.insert(getUSRForDecl(RecordDecl));
+      return;
+    }
     RecordDecl = RecordDecl->getDefinition();
     if (const auto *ClassTemplateSpecDecl =
             dyn_cast<ClassTemplateSpecializationDecl>(RecordDecl))
Index: cfe/trunk/test/clang-rename/ForwardClassDecl.cpp
===================================================================
--- cfe/trunk/test/clang-rename/ForwardClassDecl.cpp
+++ cfe/trunk/test/clang-rename/ForwardClassDecl.cpp
@@ -0,0 +1,4 @@
+class Foo; // CHECK: class Bar;
+Foo *f();  // CHECK: Bar *f();
+
+// RUN: clang-rename -offset=6 -new-name=Bar %s --  | sed 's,//.*,,' | FileCheck %s