[Issue 23278] Can't pass alias member to a function

Jul 31, 2022

Marcelo Silva Nascimento Mancini

Aug 01, 2022

anonymous4

Aug 08, 2022

anonymous4

Aug 08, 2022

Marcelo Silva Nascimento Mancini

Aug 08, 2022

Marcelo Silva Nascimento Mancini

Aug 09, 2022

RazvanN

Aug 09, 2022

Marcelo Silva Nascimento Mancini

Aug 10, 2022

Boris Carvajal

Dec 17, 2022

Iain Buclaw

Dec 13

dlangBugzillaToGithub

https://issues.dlang.org/show_bug.cgi?id=23278 Marcelo Silva Nascimento Mancini <msnmancini@hotmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |msnmancini@hotmail.com --

https://issues.dlang.org/show_bug.cgi?id=23278 RazvanN <razvan.nitu1305@gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |razvan.nitu1305@gmail.com --- Comment #3 from RazvanN <razvan.nitu1305@gmail.com> --- (In reply to Marcelo Silva Nascimento Mancini from comment #0) > This trivial code fails to compile with the error message: `onlineapp.Test2.mxString!(oops).mxString` need `this` to access member `mxString` > > ```d > class Test2 > { > string oops; > mixin(mxString!(oops)); > } > enum mxString(alias c)() > { > return ""; > } > ``` > > This should compile as there is no dependent usage on "this". Plus, the message is obviously wrong as there is no member named `mxString`. > > A real use case for that is: > ```d > enum mxString(alias c)() > { > return typeof(c).stringof~" "~c.stringof~c.stringof~";"; > } > ``` > Which does not depends on "this", as some code like `mxString!(typeof(oops), > oops.stringof)` would work. > > Mixin template does not have this limitation, so, I believe a normal function should not too. I don't really understand what you are trying to achieve here? mixin templates are used to insert declarations in a scope. If you want to mixin a function, why not declare mxString as: ``` class Test2 { string oops; mixin mxTempl!(oops); } mixin template mxTempl(alias c) { enum mxString() { return ""; } } ``` This is an enhancement request at best. However, I don't really see the point of this code. Why would you want to insert a publicly declared template in the scope of an aggregate? Why not just call the function template when it is needed with the appropriate template parameter? --

August 09, 2022

[Issue 23278] Can't pass alias member to a function

Posted by Marcelo Silva Nascimento Mancini

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Marcelo Silva Nascimento Mancini

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https://issues.dlang.org/show_bug.cgi?id=23278

--- Comment #4 from Marcelo Silva Nascimento Mancini <msnmancini@hotmail.com> ---
(In reply to RazvanN from comment #3)
> (In reply to Marcelo Silva Nascimento Mancini from comment #0)
> > This trivial code fails to compile with the error message: `onlineapp.Test2.mxString!(oops).mxString` need `this` to access member `mxString`
> > 
> > ```d
> > class Test2
> > {
> >     string oops;
> >     mixin(mxString!(oops));
> > }
> > enum mxString(alias c)()
> > {
> >     return "";
> > }
> > ```
> > 
> > This should compile as there is no dependent usage on "this". Plus, the message is obviously wrong as there is no member named `mxString`.
> > 
> > A real use case for that is:
> > ```d
> > enum mxString(alias c)()
> > {
> >     return typeof(c).stringof~" "~c.stringof~c.stringof~";";
> > }
> > ```
> > Which does not depends on "this", as some code like `mxString!(typeof(oops),
> > oops.stringof)` would work.
> > 
> > Mixin template does not have this limitation, so, I believe a normal function should not too.
> 
> I don't really understand what you are trying to achieve here? mixin templates are used to insert declarations in a scope. If you want to mixin a function, why not declare mxString as:
> 
> ```
> class Test2
> {
>     string oops;
>     mixin mxTempl!(oops);
> 
> }
> 
> mixin template mxTempl(alias c)
> {
>     enum mxString()
>     {
>         return "";
>     }
> }
> ```
> 
> This is an enhancement request at best. However, I don't really see the point of this code. Why would you want to insert a publicly declared template in the scope of an aggregate? Why not just call the function template when it is needed with the appropriate template parameter?

Because I don't want to deal with mixin template overloads. When they are executed, its overloads becomes inside them, so, I'm doing a code for using string mixin instead. If I wish to generate the overloads using mixin template, I must do `alias overload = mixed.overload;` for each function defined inside it.

If I wish to iterate through its overloads and alias to them, I must do a named mixin template, which will actually be inserted on its namespace. This can be solved by doing another mixin template which actually executes a static foreach over members from the named mixin template and generate the alias declarations. This is literally fighting the language.

--

https://issues.dlang.org/show_bug.cgi?id=23278 Boris Carvajal <boris2.9@gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |boris2.9@gmail.com --- Comment #5 from Boris Carvajal <boris2.9@gmail.com> --- I think this is a known bug, there are some reports in the past of similar compiler behavior. Related issues 17435, 18969, 20077, 22497. Put 'static' in the definition as a workaround. static enum mxString(alias c)() { return ""; } --

https://issues.dlang.org/show_bug.cgi?id=23278 Iain Buclaw <ibuclaw@gdcproject.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Priority|P1 |P3 --

https://issues.dlang.org/show_bug.cgi?id=23278 --- Comment #6 from dlangBugzillaToGithub <robert.schadek@posteo.de> --- THIS ISSUE HAS BEEN MOVED TO GITHUB https://github.com/dlang/dmd/issues/20137 DO NOT COMMENT HERE ANYMORE, NOBODY WILL SEE IT, THIS ISSUE HAS BEEN MOVED TO GITHUB --

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