[Patch, libstdc++/64239] Use std::swap instead of swap in regex

[Jonathan Wakely]

On 06/01/15 21:03 -0800, Tim Shen wrote:
>Bootstrapped and tested. It could be also patched to 4.9 branch.
>
>Thanks!
>
>
>-- 
>Regards,
>Tim Shen

>commit dfe3a26759893849020a659b14fafe8b27e90dae
>Author: timshen <timshen@google.com>
>Date:   Tue Jan 6 19:30:27 2015 -0800
>
>    	PR libstdc++/64239
>

No blank line here in the ChangeLog.

>    	* include/bits/regex.h (match_results<>::swap): Use std::swap
>    	instead of swap.
>    	* include/bits/regex_compiler.tcc (_Compiler<>::_M_quantifier):
>    	Likewise.
>
>diff --git a/libstdc++-v3/include/bits/regex.h b/libstdc++-v3/include/bits/regex.h
>index 9b7ed8c..b520039 100644
>--- a/libstdc++-v3/include/bits/regex.h
>+++ b/libstdc++-v3/include/bits/regex.h
>@@ -1864,7 +1864,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
>       swap(match_results& __that)
>       {
> 	_Base_type::swap(__that);
>-	swap(_M_begin, __that._M_begin);
>+	std::swap(_M_begin, __that._M_begin);

This is swapping iterators, which can be user-defined types, so it
should support finding a swap function by ADL, i.e.

        using std::swap;
        swap(_M_begin, __that._M_begin);

>       }
>       //@}

Also, there should be a new test, since apparently we don't have any
test that tries to call match_results::swap(match_results&).