Index: lib/Sema/SemaExprMember.cpp
===================================================================
--- lib/Sema/SemaExprMember.cpp
+++ lib/Sema/SemaExprMember.cpp
@@ -1568,6 +1568,9 @@
       // Also must look for a getter name which uses property syntax.
       Selector Sel = S.PP.getSelectorTable().getNullarySelector(Member);
       ObjCInterfaceDecl *IFace = MD->getClassInterface();
+      if (!IFace)
+        goto fail;
+
       ObjCMethodDecl *Getter;
       if ((Getter = IFace->lookupClassMethod(Sel))) {
         // Check the use of this method.
Index: test/SemaObjC/undef-class-property-error.m
===================================================================
--- /dev/null
+++ test/SemaObjC/undef-class-property-error.m
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+@implementation I (C) // expected-error {{cannot find interface declaration for 'I'}}
+
++ (void)f {
+  self.m; // expected-error {{member reference base type 'Class' is not a structure or union}}
+}
+
+@end