https://issues.dlang.org/show_bug.cgi?id=24720

RazvanN <razvan.nitu1305@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |razvan.nitu1305@gmail.com
         Resolution|---                         |DUPLICATE

--- Comment #1 from RazvanN <razvan.nitu1305@gmail.com> ---
The issue has nothing to do with __traits(getMember). It's the alias that's the
problem:

struct T
{
        void myFun(int x) {}
}
T instance;

void test()
{
        alias fun = instance.myFun;
        fun(10); // error: instance required
}

The problem is that you cannot alias an expression, only symbols or types. The problem here seems to be that the fun alias is accepted, but the compiler actually aliases to the T.myFun symbol which is not attached to any particular symbol. Looking at the docs [1] I see that the last runnable line in the example is commented (alias c = s.j) is commented out with a "scheduled for deprecation" comment, so I assume that this was discussed at some point.

PS: this has been reported in the past multiple times: https://issues.dlang.org/show_bug.cgi?id=6842 .


[1] https://dlang.org/spec/declaration.html#alias-variable

*** This issue has been marked as a duplicate of issue 6842 ***

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https://issues.dlang.org/show_bug.cgi?id=24720

--- Comment #2 from RazvanN <razvan.nitu1305@gmail.com> ---
(In reply to RazvanN from comment #1)
> The issue has nothing to do with __traits(getMember). It's the alias that's
> the problem:
> 
> struct T
> {
> 	void myFun(int x) {}
> }
> T instance;
> 
> void test()
> {
> 	alias fun = instance.myFun;
> 	fun(10); // error: instance required
> }
> 
> The problem is that you cannot alias an expression, only symbols or types. The problem here seems to be that the fun alias is accepted, but the compiler actually aliases to the T.myFun symbol which is not attached to any particular symbol. Looking at the docs [1] I see that the last runnable line in the example is commented (alias c = s.j) is commented out with a "scheduled for deprecation" comment, so I assume that this was discussed at some point.
> 
> PS: this has been reported in the past multiple times: https://issues.dlang.org/show_bug.cgi?id=6842 .
> 
> 
> [1] https://dlang.org/spec/declaration.html#alias-variable
> 
> *** This issue has been marked as a duplicate of issue 6842 ***

I meant: "but the compiler actually aliases to the T.myFun symbol which is not attached to any particular instance". Sorry for the confusion.

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https://issues.dlang.org/show_bug.cgi?id=24720

Nick Treleaven <nick@geany.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |nick@geany.org

--- Comment #3 from Nick Treleaven <nick@geany.org> ---
> 	alias fun = instance.myFun;

Thanks, should get detected with https://github.com/dlang/dmd/pull/16813.

> Looking at the docs [1] I see that the last runnable line in the example is commented (alias c = s.j) is commented out with a "scheduled for deprecation" comment

Walter said we shouldn't add a deprecation for this (probably because if people understood it, it might deprecate correct code): https://github.com/dlang/dmd/pull/15863#issuecomment-1902711081

I should update that comment though.

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https://issues.dlang.org/show_bug.cgi?id=24720

--- Comment #4 from Manu <turkeyman@gmail.com> ---
Sorry, but what is this a duplicate of?
It's definitely not fixed...

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https://issues.dlang.org/show_bug.cgi?id=24720

--- Comment #5 from RazvanN <razvan.nitu1305@gmail.com> ---
(In reply to Manu from comment #4)
> Sorry, but what is this a duplicate of?
> It's definitely not fixed...

It's a duplicate of issue 6842: https://issues.dlang.org/show_bug.cgi?id=6842 which indeed is not fixed.

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https://issues.dlang.org/show_bug.cgi?id=24720

--- Comment #6 from Manu <turkeyman@gmail.com> ---
Oh sorry, I thought I saw that it was closed too. My mistake!

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https://issues.dlang.org/show_bug.cgi?id=24720

--- Comment #7 from RazvanN <razvan.nitu1305@gmail.com> ---
No worries!

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