Compiler bug? (alias sth this; and std.signals)

[Joe]

Why would is(T == struct) be true but !isBuiltinType!T be false?
This seems highly inconsistent. If T is a struct, it is not a
builtin type, and if T is int (also making the condition false),
then Property should never have been passed as a struct, but as
the int gotten via the alias.

On Thursday, 15 November 2012 at 14:52:41 UTC, eskimo wrote:
> :-) Indeed, that is the only thing that surprised me too (but 
> not as
> much as in another language, because of D's capabilities). The 
> solution
> I think is this overload found in std.format of formatValue:
>
> void formatValue(Writer, T, Char)(Writer w, auto ref T val, ref
> FormatSpec!Char f)
> if ((is(T == struct) || is(T == union)) && (hasToString!(T, 
> Char) || !
> isBuiltinType!T) && !is(T == enum))
>
> -> Its body implements the generic print for structs. It either 
> calls
> the structs toString() method if available or if it is a range 
> it uses
> formatRange() otherwise it prints its type name with its 
> contained
> values.
> But as you can see the templates requirement states 
> !isBuiltinType!T, so
> in case of your alias this to an int, it won't be used. So the
> implementer of this method most likely had taken into account 
> the
> possibility of an alias this to a built in type.
>
> Btw., I love D's readability, it was really easy to find this 
> and to
> understand what it does.
>
> Best regards,
>
> Robert