diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index d1906e0d0057..ea3f61fdc895 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -2490,6 +2490,7 @@ void ASTDeclReader::attachPreviousDeclImpl(ASTReader &Reader,
                                            Decl *Previous) {
   D->RedeclLink.setPrevious(cast<DeclT>(Previous));
 }
+namespace clang {
 template<>
 void ASTDeclReader::attachPreviousDeclImpl(ASTReader &Reader,
                                            Redeclarable<FunctionDecl> *D,
@@ -2534,6 +2535,7 @@ void ASTDeclReader::attachPreviousDeclImpl(ASTReader &Reader,
         FPT->getExtProtoInfo().withExceptionSpec(EPI.ExceptionSpec)));
   }
 }
+}
 void ASTDeclReader::attachPreviousDeclImpl(ASTReader &Reader, ...) {
   llvm_unreachable("attachPreviousDecl on non-redeclarable declaration");
 }