1 files changed, 7 insertions, 3 deletions
diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index 67ea68928d..00a48e9396 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -2647,11 +2647,15 @@ Sema::FinishTemplateArgumentDeduction(FunctionTemplateDecl *FunctionTemplate,
       if (CurrentInstantiationScope &&
           CurrentInstantiationScope->getPartiallySubstitutedPack(&ExplicitArgs,
                                                              &NumExplicitArgs)
-          == Param)
+            == Param) {
         Builder.push_back(TemplateArgument(ExplicitArgs, NumExplicitArgs));
-      else
-        Builder.push_back(TemplateArgument::getEmptyPack());
 
+        // Forget the partially-substituted pack; it's substitution is now
+        // complete.
+        CurrentInstantiationScope->ResetPartiallySubstitutedPack();
+      } else {
+        Builder.push_back(TemplateArgument::getEmptyPack());
+      }
       continue;
     }