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digitalmars.D.learn - Template Mixin Conflicts

reply "Alice" <a.blunt ibexinnovations.co.uk> writes:
Hi,


I've created a template mixin which contains a struct definition. 
The template is meant to be mixed into each module - to provide a 
little bit of auto generated info in each module - generated at 
compile time. As soon as I reference the symbols in any context, 
it starts complaining about conflicts between the two modules.

It doesn't have to be a struct; the conflicts exist whether I 
define a struct, class, function, or whatever... any symbol.

It is valid to manually define symbols with the same name in 
different modules, since they each exist in a different scope, so 
why does a symbol brought in by a mixin conflict?

Even defining the struct as private doesn't help. Any ideas would 
be most appreciated.


Here's a very simple failing case:


// ModuleA.d
module ModuleA;

import ModuleB;

mixin MixinUsefulStuff;

pragma(msg, "a = ", SomeData.a); // Error: 
ModuleB.MixinUsefulStuff!().SomeData at ModuleB.d(5) conflicts 
with ModuleA.MixinUsefulStuff!().SomeData at ModuleB.d(5)


// ModuleB.d
module ModuleB;

mixin template MixinUsefulStuff()
{
	struct SomeData
	{
		enum a = 123;
	}
}

mixin MixinUsefulStuff;
Oct 06 2014
next sibling parent "Alice" <a.blunt ibexinnovations.co.uk> writes:
And just this second I found this... but it's a few months old 
and has no follow up.

http://forum.dlang.org/thread/mailman.1054.1398548687.2763.digitalmars-d-bugs puremagic.com


On Monday, 6 October 2014 at 12:17:01 UTC, Alice wrote:

 Hi,


 I've created a template mixin which contains a struct 
 definition. The template is meant to be mixed into each module 
 - to provide a little bit of auto generated info in each module 
 - generated at compile time. As soon as I reference the symbols 
 in any context, it starts complaining about conflicts between 
 the two modules.

 It doesn't have to be a struct; the conflicts exist whether I 
 define a struct, class, function, or whatever... any symbol.

 It is valid to manually define symbols with the same name in 
 different modules, since they each exist in a different scope, 
 so why does a symbol brought in by a mixin conflict?

 Even defining the struct as private doesn't help. Any ideas 
 would be most appreciated.


 Here's a very simple failing case:


 // ModuleA.d
 module ModuleA;

 import ModuleB;

 mixin MixinUsefulStuff;

 pragma(msg, "a = ", SomeData.a); // Error: 
 ModuleB.MixinUsefulStuff!().SomeData at ModuleB.d(5) conflicts 
 with ModuleA.MixinUsefulStuff!().SomeData at ModuleB.d(5)


 // ModuleB.d
 module ModuleB;

 mixin template MixinUsefulStuff()
 {
 	struct SomeData
 	{
 		enum a = 123;
 	}
 }

 mixin MixinUsefulStuff;
Oct 06 2014
prev sibling parent reply ketmar via Digitalmars-d-learn <digitalmars-d-learn puremagic.com> writes:
On Mon, 06 Oct 2014 12:17:00 +0000
Alice via Digitalmars-d-learn <digitalmars-d-learn puremagic.com> wrote:

the joy of mixin bugs, yeah! it's a bug in compiler: it instantiates
mixin in invalid scope. for now you can use string mixins, they are
working fine.

you also can use this to fix scoping:

=3D=3D=3D ModuleA.d =3D=3D=3D

  module ModuleA;
  static import ModuleB;
  mixin ModuleB.MixinUsefulStuff;
  pragma(msg, "a =3D ", SomeData.a);

btw, do you mind to fill a bugreport?
Oct 06 2014
next sibling parent "Alice" <a.blunt ibexinnovations.co.uk> writes:
 btw, do you mind to fill a bugreport?


Okay, will do so once I get home from work. Thanks for the scope 
tip. Will try that out later too.
Oct 06 2014
prev sibling parent reply =?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:
On 10/06/2014 05:50 AM, ketmar via Digitalmars-d-learn wrote:

 On Mon, 06 Oct 2014 12:17:00 +0000
 Alice via Digitalmars-d-learn <digitalmars-d-learn puremagic.com> wrote:

 the joy of mixin bugs, yeah! it's a bug in compiler: it instantiates
 mixin in invalid scope. for now you can use string mixins, they are
 working fine.

 you also can use this to fix scoping:

 === ModuleA.d ===

    module ModuleA;
    static import ModuleB;
    mixin ModuleB.MixinUsefulStuff;
    pragma(msg, "a = ", SomeData.a);

 btw, do you mind to fill a bugreport?


Another workaround is to mixin into a scope and then bring the names out 
by alias. Doing the following in both files works:

struct MixinUsefulStuffWrapper
{
     mixin MixinUsefulStuff;
}

alias SomeData = MixinUsefulStuffWrapper.SomeData;

Ali
Oct 06 2014
parent "Alice" <a.blunt ibexinnovations.co.uk> writes:
Thanks for your help guys. The workarounds will do for now.

The bug is here: https://issues.dlang.org/show_bug.cgi?id=13587
Oct 08 2014