diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index 08384cc..868458c 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -3801,7 +3801,8 @@
   for (TemplateParameterList::iterator OldParm = Old->begin(),
                                     OldParmEnd = Old->end();
        OldParm != OldParmEnd; ++OldParm) {
-    if (!(*OldParm)->isTemplateParameterPack()) {
+    if (Kind != TPL_TemplateTemplateArgumentMatch ||
+        !(*OldParm)->isTemplateParameterPack()) {
       if (NewParm == NewParmEnd) {
         if (Complain)
           DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
diff --git a/test/CXX/temp/temp.decls/temp.variadic/parameter-matching.cpp b/test/CXX/temp/temp.decls/temp.variadic/parameter-matching.cpp
index 3fc774c..989ff9f 100644
--- a/test/CXX/temp/temp.decls/temp.variadic/parameter-matching.cpp
+++ b/test/CXX/temp/temp.decls/temp.variadic/parameter-matching.cpp
@@ -25,3 +25,19 @@
 
 template<template<class T> class> class X1tt; // expected-note{{previous template template parameter declared here}}
 template<template<class T> class...> class X1tt; // expected-error{{template template parameter pack conflicts with previous template template parameter}}
+
+// Check for matching with out-of-line definitions
+namespace rdar8859985 {
+  template<typename ...> struct tuple { };
+  template<int ...> struct int_tuple { };
+
+  template<typename T>
+  struct X {
+    template<typename ...Args1, int ...Indices1>
+    X(tuple<Args1...>, int_tuple<Indices1...>);
+  };
+
+  template<typename T>
+  template<typename ...Args1, int ...Indices1>
+  X<T>::X(tuple<Args1...>, int_tuple<Indices1...>) {}
+}