Re: alias and UDAs

[Stanislav Blinov via Digitalmars-d-learn]

On Thursday, 11 May 2017 at 10:39:03 UTC, Andre Pany wrote:
Hi,
in this example, both asserts fails. Is my assumption right, 
that UDA on alias have no effect? If yes, I would like to see a 
compiler warning.

But anyway, I do not understand why the second assertion fails. 
Are UDAs on arrays not allowed?

import std.traits: hasUDA;

enum Flattened;

struct Foo
{
        int bar;
}

@Flattened alias FooList = Foo[];

struct Baz
{
        FooList fooList1;
        @Flattened FooList[] fooList2;
}

void main()
{       
        Baz baz;
        static assert(hasUDA!(baz.fooList1, "Flattened")); // => false
        static assert(hasUDA!(baz.fooList2, "Flattened")); // => false
}

Kind regards
André

It should've been

alias FooList = @Flattened Foo[];

which will generate a compile-time error (UDAs not allowed for 
alias declarations).

And then:

static assert(hasUDA!(baz.fooList2, Flattened));

No quotes, since Flattened is an enum, not a string