bug in compiles?

[Alex]

On Thursday, 11 April 2019 at 19:42:05 UTC, Steven Schveighoffer 
wrote:
> On 4/11/19 2:13 PM, Alex wrote:
>> The following code works when I comment out the static if
>> 
>> //static if (__traits(compiles, __traits(getAttributes, T)))
>>     static foreach(a;  __traits(getAttributes, T)) Attributes 
>> ~=
>> 
>> 
>> There seems to be absolutely no reason why this code would 
>> fail with the static if but pass without it but in the first 
>> case I get no attributes because the __traits compiles fails.
>> 
>> 
>> 
>> __traits(compiles, __traits(getAttributes, T))
>> 
>> vs
>> 
>> __traits(getAttributes, T)
>> 
>> How could it not compile in the first case and yet work in the 
>> foreach?
>
> It should. Do you have a larger example? One that can be played 
> with?
>
> -Steve

import std.stdio, std.traits, std.conv;


struct A(alias T)
{
     static void foo()
     {
		static if (__traits(compiles, __traits(getAttributes, T))) // 
Failing for some reason
		    static foreach(a;  __traits(getAttributes, T)) pragma(msg, 
to!string(a), "-", typeof(a).stringof);
     }
}

void main()
{
     @(3) int a;

     (A!a).foo();
}

Commenting out the static if allows the foreach to pass and 
everything works. The whole point of the static if is to let the 
foreach work.

Both are only dependent on

__traits(getAttributes, T)

So if that can't compile then how could the foreach work?

https://run.dlang.io/is/WlXCIZ