<div dir="ltr">This change stands on it's own. But I think there were another couple of <variant> bug fixes in the past week.<div>I'm going to look into merging those as well.</div><div><br></div><div>/Eric</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Feb 9, 2017 at 2:56 PM, Hans Wennborg <span dir="ltr"><<a href="mailto:hans@chromium.org" target="_blank">hans@chromium.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Sounds good to me. You said "these changes"; are there more than this one?<br>
<div class="HOEnZb"><div class="h5"><br>
On Thu, Feb 9, 2017 at 11:15 AM, Eric Fiselier <<a href="mailto:eric@efcs.ca">eric@efcs.ca</a>> wrote:<br>
> I'm planning to merge this fix into the 4.0 release branch.<br>
><br>
> Although not a regression, since <variant> is a new feature, it would still<br>
> be nice to ship without this bug.<br>
><br>
> I'll merge these changes later today if there are no objections, and once<br>
> all the bots pass.<br>
><br>
> /Eric<br>
><br>
> On Thu, Feb 9, 2017 at 12:01 PM, Eric Fiselier via cfe-commits<br>
> <<a href="mailto:cfe-commits@lists.llvm.org">cfe-commits@lists.llvm.org</a>> wrote:<br>
>><br>
>> Author: ericwf<br>
>> Date: Thu Feb  9 13:01:22 2017<br>
>> New Revision: 294612<br>
>><br>
>> URL: <a href="http://llvm.org/viewvc/llvm-project?rev=294612&view=rev" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project?rev=294612&view=rev</a><br>
>> Log:<br>
>> Fix PR31916 - std::visit rejects visitors accepting lvalue arguments<br>
>><br>
>> A static assertion was misfiring since it checked<br>
>> is_callable<Visitor, decltype(__variant_alt<T>.<wbr>value)>. However<br>
>> the decltype expression doesn't capture the value category as<br>
>> required. This patch applies extra braces to decltype to fix<br>
>> that.<br>
>><br>
>> Modified:<br>
>>     libcxx/trunk/include/variant<br>
>>     libcxx/trunk/test/std/<wbr>utilities/variant/variant.<wbr>visit/visit.pass.cpp<br>
>><br>
>> Modified: libcxx/trunk/include/variant<br>
>> URL:<br>
>> <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/variant?rev=294612&r1=294611&r2=294612&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/libcxx/trunk/include/<wbr>variant?rev=294612&r1=294611&<wbr>r2=294612&view=diff</a><br>
>><br>
>> ==============================<wbr>==============================<wbr>==================<br>
>> --- libcxx/trunk/include/variant (original)<br>
>> +++ libcxx/trunk/include/variant Thu Feb  9 13:01:22 2017<br>
>> @@ -578,7 +578,7 @@ private:<br>
>>      constexpr decltype(auto) operator()(_Alts&&... __alts) const {<br>
>>        __std_visit_exhaustive_<wbr>visitor_check<<br>
>>            _Visitor,<br>
>> -          decltype(_VSTD::forward<_Alts><wbr>(__alts).__value)...>();<br>
>> +          decltype((_VSTD::forward<_<wbr>Alts>(__alts).__value))...>();<br>
>>        return __invoke_constexpr(_VSTD::<wbr>forward<_Visitor>(__visitor),<br>
>><br>
>> _VSTD::forward<_Alts>(__alts).<wbr>__value...);<br>
>>      }<br>
>><br>
>> Modified:<br>
>> libcxx/trunk/test/std/<wbr>utilities/variant/variant.<wbr>visit/visit.pass.cpp<br>
>> URL:<br>
>> <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/utilities/variant/variant.visit/visit.pass.cpp?rev=294612&r1=294611&r2=294612&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/libcxx/trunk/test/std/<wbr>utilities/variant/variant.<wbr>visit/visit.pass.cpp?rev=<wbr>294612&r1=294611&r2=294612&<wbr>view=diff</a><br>
>><br>
>> ==============================<wbr>==============================<wbr>==================<br>
>> --- libcxx/trunk/test/std/<wbr>utilities/variant/variant.<wbr>visit/visit.pass.cpp<br>
>> (original)<br>
>> +++ libcxx/trunk/test/std/<wbr>utilities/variant/variant.<wbr>visit/visit.pass.cpp<br>
>> Thu Feb  9 13:01:22 2017<br>
>> @@ -283,9 +283,20 @@ void test_exceptions() {<br>
>>  #endif<br>
>>  }<br>
>><br>
>> +// See <a href="http://llvm.org/PR31916" rel="noreferrer" target="_blank">http://llvm.org/PR31916</a><br>
>> +void test_caller_accepts_nonconst() {<br>
>> +  struct A {};<br>
>> +  struct Visitor {<br>
>> +    void operator()(A&) {}<br>
>> +  };<br>
>> +  std::variant<A> v;<br>
>> +  std::visit(Visitor{}, v);<br>
>> +}<br>
>> +<br>
>>  int main() {<br>
>>    test_call_operator_forwarding(<wbr>);<br>
>>    test_argument_forwarding();<br>
>>    test_constexpr();<br>
>>    test_exceptions();<br>
>> +  test_caller_accepts_nonconst()<wbr>;<br>
>>  }<br>
>><br>
>><br>
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><br>
</div></div></blockquote></div><br></div>