diff --git a/libstdc++-v3/include/bits/regex.h b/libstdc++-v3/include/bits/regex.h
index 785edc71800..52dcd7f86ae 100644
--- a/libstdc++-v3/include/bits/regex.h
+++ b/libstdc++-v3/include/bits/regex.h
@@ -35,7 +35,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
   template<typename, typename>
     class basic_regex;
 
-  template<typename, typename>
+  template<typename _Bi_iter, typename _Alloc>
     class match_results;
 
 _GLIBCXX_END_NAMESPACE_CXX11
@@ -2109,7 +2109,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
       _M_suffix()
       { return _Unchecked::operator[](_Unchecked::size() - 1); }
 
-      _Bi_iter _M_begin;
+      _Bi_iter _M_begin {};
       /// @endcond
     };