Index: lib/Sema/SemaExprCXX.cpp
===================================================================
--- lib/Sema/SemaExprCXX.cpp
+++ lib/Sema/SemaExprCXX.cpp
@@ -113,6 +113,8 @@
       break;
     }
   }
+  if (!InjectedClassName && CurClass->isInvalidDecl())
+    return ParsedType();
   assert(InjectedClassName && "couldn't find injected class name");
 
   QualType T = Context.getTypeDeclType(InjectedClassName);
Index: test/SemaCXX/injected-class-name-crash.cpp
===================================================================
--- test/SemaCXX/injected-class-name-crash.cpp
+++ test/SemaCXX/injected-class-name-crash.cpp
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+template <class T>
+struct X : public Foo<Bar { // expected-error {{unknown template name 'Foo'}} expected-error {{use of undeclared identifier 'Bar'}}
+  X();
+}; // expected-error {{expected '{' after base class list}}
+
+
+template <class T>
+X<T>::X() {
+}