diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index caeea58..a55193a 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2323,6 +2323,24 @@
     VarDecl *Var = cast<VarDecl>(Inst.first);
     assert(Var->isStaticDataMember() && "Not a static data member?");
 
+    // Don't try to instantiate declarations if the most recent redeclaration
+    // is invalid.
+    if (Var->getMostRecentDeclaration()->isInvalidDecl())
+      continue;
+
+    // Check if the most recent declaration has changed the specialization kind
+    // and removed the need for implicit instantiation.
+    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
+    case TSK_Undeclared:
+      assert(false && "Cannot instantitiate an undeclared specialization.");
+    case TSK_ExplicitInstantiationDeclaration:
+    case TSK_ExplicitInstantiationDefinition:
+    case TSK_ExplicitSpecialization:
+      continue;  // No longer need implicit instantiation.
+    case TSK_ImplicitInstantiation:
+      break;
+    }
+
     PrettyStackTraceActionsDecl CrashInfo(DeclPtrTy::make(Var),
                                           Var->getLocation(), *this,
                                           Context.getSourceManager(),
diff --git a/test/SemaTemplate/explicit-instantiation.cpp b/test/SemaTemplate/explicit-instantiation.cpp
index 227856f..de51f09 100644
--- a/test/SemaTemplate/explicit-instantiation.cpp
+++ b/test/SemaTemplate/explicit-instantiation.cpp
@@ -76,3 +76,10 @@
 // PR5069
 template<int I> void foo0 (int (&)[I + 1]) { }
 template void foo0<2> (int (&)[3]);
+
+namespace explicit_instantiation_after_implicit_instantiation {
+  template <int I> struct X0 { static int x; };
+  template <int I> int X0<I>::x;
+  void test1() { (void)&X0<1>::x; }
+  template struct X0<1>;
+}