Hi,

I want to validate whether a class contains a specific attribute. I have the attribute name as compile time string. This string could either be a direct attribute of the class or a hierarchy (TextSettings.Font.Size).

As example T is the class Label and p.name contains the text "TextSettings.Font.Size".
TextSettings and Font are again classes.

mixin(`static if (__traits(compiles, `~fullyQualifiedName!T~`.`~p.name~`)) {...}

__traits(compiles, ...) only works for symbols of the same module, but not for symbols contained in other modules. I reduced it to this example coding:

m1.d
-----------------
module m1;

import m2;

class Foo
{
	int foo;
}

void main()
{
	static assert(__traits(compiles, m1.Foo.foo));
	static assert(__traits(compiles, m2.Bar.bar));
}

m2.d
---------------
module m2;

class Bar
{
	int bar;
}

Why does the second assert throws? What can I use instead of __traits(compiles,...) ?

Kind regards
André

On 07/24/2017 11:40 PM, Andre Pany wrote:
> m1.d
> -----------------
> module m1;
> 
> import m2;
> 
> class Foo
> {
>      int foo;
> }
> 
> void main()
> {
>      static assert(__traits(compiles, m1.Foo.foo));
>      static assert(__traits(compiles, m2.Bar.bar));
> }
> 
> m2.d
> ---------------
> module m2;
> 
> class Bar
> {
>      int bar;
> }
> 
> Why does the second assert throws? What can I use instead of __traits(compiles,...) ?

Works for me. What compiler are you using?

On Tuesday, 25 July 2017 at 08:30:43 UTC, ag0aep6g wrote:
> Works for me. What compiler are you using?

I reduced the example too lot. The issue is occuring if there is also a package.d is involved.

m1.d
-----------------------

module m1;

import sub; // Does not throw if replaced with: import sub.m2;

class Foo
{
	int foo;
}

void main()
{
	static assert(__traits(compiles, m1.Foo.foo));
	mixin(`static assert(__traits(compiles, sub.m2.Bar.bar));`);
}

sub/m2.d
----------------------

module sub.m2;

class Bar
{
	int bar;
}

sub/package.d
----------------------

module sub;

public import sub.m2;


I use DMD master (as I already need the static foreach) on windows 10.
DMD32 D Compiler v2.075.0-rc1-master-af3eacf

>> dmd -run m1.d sub/package.d sub/m2.d

Kind regards
André

On Tuesday, 25 July 2017 at 11:34:23 UTC, Andre Pany wrote:
> On Tuesday, 25 July 2017 at 08:30:43 UTC, ag0aep6g wrote:
>> Works for me. What compiler are you using?
>
> I reduced the example too lot. The issue is occuring if there is also a package.d is involved.
>
> m1.d
> -----------------------
>
> module m1;
>
> import sub; // Does not throw if replaced with: import sub.m2;
>
> class Foo
> {
> 	int foo;
> }
>
> void main()
> {
> 	static assert(__traits(compiles, m1.Foo.foo));
> 	mixin(`static assert(__traits(compiles, sub.m2.Bar.bar));`);
> }
>
> sub/m2.d
> ----------------------
>
> module sub.m2;
>
> class Bar
> {
> 	int bar;
> }
>
> sub/package.d
> ----------------------
>
> module sub;
>
> public import sub.m2;
>
>
> I use DMD master (as I already need the static foreach) on windows 10.
> DMD32 D Compiler v2.075.0-rc1-master-af3eacf
>
>>> [...]
>
> Kind regards
> André

Issue created: https://issues.dlang.org/show_bug.cgi?id=17683

Is there a known workaround?

Kind regards
André