[UDA] Error: first argument is not a symbol

[Jonathan M Davis via Digitalmars-d-learn]

On Thursday, September 15, 2016 08:56:18 Steven Schveighoffer via Digitalmars-
d-learn wrote:
> On 9/15/16 4:48 AM, drug wrote:
> > https://dpaste.dzfl.pl/9548c481ce46
> >
> > shouldn't commented line return 'false' as built-in type 'int' has no
> > any UDAs instead of cryptic (for me) message about wrong first argument?
>
> This is due to int not being a symbol, which apparently
> __traits(getAttributes, ...) requires.
>
> int is a keyword and not considered a symbol. An annoying distinction
> without a difference in this case. I'd say it's something we should fix,
> but this kind of problem has existed forever. Not sure if it will get
> attention.

Given the fact that Walter theoretically agreed to fix it so that alias
parameters accepted built-in types and not just symbols, that might
translate to treating int and friends as symbols in general, which would fix
this case. I don't know.

There's certainly no need to ever check whether a built-in type has a UDA,
because it never will, so in that respect, it doesn't really matter, but it
could become annoying in generic code, because you might have to explicitly
check for built-in symbols to workaround this.

I've opened an enhancement request:

https://issues.dlang.org/show_bug.cgi?id=16496

- Jonathan M Davis