For example

class A
{
    @recursive @safe void talk()
    {
        writeln("Hi");
    }

}
class B : A
{
    override void talk() // @safe attribute added by recursive attribute and can not be removed
    {
        writeln("Bye");
    }
}

I have notice that potential bugs can slip by the compiler during compile time, and I purpose this as way to counter them.

Alex

On 03/27/2018 10:39 PM, 12345swordy wrote:
> class A
> {
>      @recursive @safe void talk()
[...]
> }
> class B : A
> {
>      override void talk() // @safe attribute added by recursive attribute and can not be removed
[...]
> }

It already works like that. B.talk is @safe, and you can't make it @system. You can mark it as @system, that gets overridden by A.talk's @safe.

https://run.dlang.io/is/BlH8bp

On Tuesday, 27 March 2018 at 20:49:25 UTC, ag0aep6g wrote:
> On 03/27/2018 10:39 PM, 12345swordy wrote:
>> class A
>> {
>>      @recursive @safe void talk()
> [...]
>> }
>> class B : A
>> {
>>      override void talk() // @safe attribute added by recursive attribute and can not be removed
> [...]
>> }
>
> It already works like that. B.talk is @safe, and you can't make it @system. You can mark it as @system, that gets overridden by A.talk's @safe.
>
> https://run.dlang.io/is/BlH8bp
Then explain this then.
https://run.dlang.io/is/S2KLs5

On 03/27/2018 11:02 PM, 12345swordy wrote:
> Then explain this then.
> https://run.dlang.io/is/S2KLs5

B.talk is @safe. The compiler ignores the @system attribute on B.talk, because A.talk's @safe attribute takes precedence.

On Tuesday, 27 March 2018 at 21:05:32 UTC, ag0aep6g wrote:
> On 03/27/2018 11:02 PM, 12345swordy wrote:
>> Then explain this then.
>> https://run.dlang.io/is/S2KLs5
>
> B.talk is @safe. The compiler ignores the @system attribute on B.talk, because A.talk's @safe attribute takes precedence.

Shouldn't it give a warning then?

On 03/27/2018 11:10 PM, 12345swordy wrote:
> Shouldn't it give a warning then?

I wouldn't mind a warning, or even an error. Putting both @safe and @system directly on a function is an error, too.

On Tuesday, 27 March 2018 at 21:25:33 UTC, ag0aep6g wrote:
> On 03/27/2018 11:10 PM, 12345swordy wrote:
>> Shouldn't it give a warning then?
>
> I wouldn't mind a warning, or even an error. Putting both @safe and @system directly on a function is an error, too.

shouldn't it create a overload?
for example this fails:

class A
{
    void talk()@safe {}
}

class B : A
{
    alias talk = A.talk;
    void talk()@system {}
}

but this works:

class A
{
    void talk() {}
}

class B : A
{
    alias talk = A.talk;
    void talk(int) {}
}

this works also:

class C
{
    void talk()@system {}
    void talk()@safe {}
}

On 03/28/2018 12:19 AM, arturg wrote:
> shouldn't it create a overload?

I don't think so. As far as I know, you can't overload on attributes.

[...]
> but this works:
> 
> class A
> {
>      void talk() {}
> }
> 
> class B : A
> {
>      alias talk = A.talk;
>      void talk(int) {}
> }

Because different parameters make overloads.

> this works also:
> 
> class C
> {
>      void talk()@system {}
>      void talk()@safe {}
> }

DMD might accept that, but I don't think it works in a meaningful way. How do you call the @system one?

Looks like the @safe one will always be called, even from @system code:

----
import std.stdio;

void talk() @system { writeln("@system"); }
void talk() @safe { writeln("@safe"); }

void main() @system
{
    talk(); /* Prints "@safe". */
}
----

On Tuesday, 27 March 2018 at 23:23:38 UTC, ag0aep6g wrote:
>
> DMD might accept that, but I don't think it works in a meaningful way. How do you call the @system one?
>
> Looks like the @safe one will always be called, even from @system code:
>
> ----
> import std.stdio;
>
> void talk() @system { writeln("@system"); }
> void talk() @safe { writeln("@safe"); }
>
> void main() @system
> {
>     talk(); /* Prints "@safe". */
> }
> ----

you can call them with __traits(getOverloads, T, "name")[index];

you can overload on types attributes and linkage, but seems like you can only merge overloads based on types.

On Tuesday, 27 March 2018 at 23:34:20 UTC, arturg wrote:
> On Tuesday, 27 March 2018 at 23:23:38 UTC, ag0aep6g wrote:
>>
>> DMD might accept that, but I don't think it works in a meaningful way. How do you call the @system one?
>>
>> Looks like the @safe one will always be called, even from @system code:
>>
>> ----
>> import std.stdio;
>>
>> void talk() @system { writeln("@system"); }
>> void talk() @safe { writeln("@safe"); }
>>
>> void main() @system
>> {
>>     talk(); /* Prints "@safe". */
>> }
>> ----
>
> you can call them with __traits(getOverloads, T, "name")[index];
>
> you can overload on types attributes and linkage, but seems like you can only merge overloads based on types.

i have some templates which can be used like this:

type.dgAt!("name", index);
dgAt!("name", index, somemodule);
dgAt!("name", index, "somemodule");
alias fun = aAt!("name", index, someTypeOrModule);

type.dgOf!("name", void function(int)@safe);
dgOf!("name", void function(int)@safe, module);
dgOf!("name", void function(int)@safe, "module");

from!(type, "name").aAt!1;
from!(type, "name").aOf!(void function(int));
from!(type, "name").dgAt!1;
from!(type, "name").dgOf!(void function(int));

but this fails:
type.dgOf!("name", extern(C) void function(int)@safe);

and this works:
alias funtype = extern(C) void function(int)@safe;
type.dgOf!("name", funtype);