__traits(compiles,...) <=> ? is(typeof(...))

[Zhenya]

On Monday, 29 October 2012 at 10:58:51 UTC, Philippe Sigaud wrote:
>> Tell me please,in this code first and second static if,are 
>> these equivalent?
>> with arg = 1, __traits(compiles,"check(arg);") = true,
>> is(typeof(check(arg))) = false.
>
> __traits(compiles, ...) takes an expression, not a string. From 
> the
> spec: "The arguments can be symbols, types, or expressions that 
> are
> syntactically correct. The arguments cannot be statements or
> declarations."
>
> (http://dlang.org/traits.html#compiles)
>
> So, in your case, that would be:
>
> __traits(compiles, {check(arg);})
>
> Note that you can also use the type of arg:
>
> __traits(compiles, {check(typeof(arg).init);})
>
> or
>
> is(typeof({ check(typeof(arg).init);})
Thank you,understood.