Don't neglect to "return *this".

llvm-svn: 165860
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 88db3171dd5dcc54e3890b6f823c60831fc520a5
diff --git a/include/regex b/include/regex
index 3918ee0..7505f2e 100644
--- a/include/regex
+++ b/include/regex
@@ -2562,6 +2562,7 @@
         {
             __member_init(__f);
             __parse(__first, __last);
+            return *this;
         }
 
 #ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS