Index: lib/Sema/SemaTemplateInstantiate.cpp
===================================================================
--- lib/Sema/SemaTemplateInstantiate.cpp
+++ lib/Sema/SemaTemplateInstantiate.cpp
@@ -1939,8 +1939,10 @@
   }
 
   InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation);
-  if (Inst.isInvalid())
+  if (Inst.isInvalid()) {
+    Instantiation->setInvalidDecl(true);
     return true;
+  }
 
   // Enter the scope of this instantiation. We don't use
   // PushDeclContext because we don't have a scope.
Index: test/SemaTemplate/instantiate-explicitly-after-fatal.cpp
===================================================================
--- /dev/null
+++ test/SemaTemplate/instantiate-explicitly-after-fatal.cpp
@@ -0,0 +1,9 @@
+// RUN: not %clang_cc1 -fsyntax-only -std=c++11 -ferror-limit 1 %s 2>&1 | FileCheck %s
+unknown_type foo(unknown_type);
+// CHECK: fatal error: too many errors emitted, stopping now
+
+template <typename>
+class Bar {};
+
+extern template class Bar<int>;
+template class Bar<int>;