[C++ Patch] PR 52174 aka DR 1423

[Jason Merrill]

On 06/03/2014 10:30 AM, Paolo Carlini wrote:
> implementing the resolution seems rather straightforward, just check
> LOOKUP_ONLYCONVERTING in standard_conversion.

Yep.  Though it would be better to return a bad_p conversion than none 
at all.

> However, while playing
> with some additional tests outside bug & testsuite (similar to
> nullptr32.C), I noticed a latent issue: in case of base initializers we
> were setting anyway LOOKUP_ONLYCONVERTING in add_function_candidate

Right.  In the case of

> +  TDerived()
> +  : TBase<T>(nullptr) { }

we have direct-initialization of TBase<T>, but the parameter of the 
TBase constructor is copy-initialized, so nullptr32.C is ill-formed; 
please drop this hunk of the patch.

Jason