Is this intended or is it a bug?

void main(string[] args)
{
	Test a;
	a.foo(5); // Fails to compile
}

struct Test
{
	mixin testMix;
	void foo(string y){}
}

mixin template testMix()
{
	void foo(int x){}
}

On Thursday, 25 June 2015 at 03:49:04 UTC, Tofu Ninja wrote:
> Is this intended or is it a bug?

Intended, the mixin template works on the basis of names. This means that you can override methods from the mixin by writing a member with the same name - very useful thing - but also means no overloading happens without an extra step.

The extra step is easy though: alias the name in:

 void main(string[] args)
 {
 	Test a;
 	a.foo(5); // works!
	a.foo("4qsda");
 }

 struct Test
 {
 	mixin testMix tm; // give it a name to reference later
 	void foo(string y){}
	alias tm.foo foo; // alias the mixin thing too
 }

 mixin template testMix()
 {
 	void foo(int x){}
 }



By adding that explicit alias, it tells the compiler that yes, you do want it added to the set, not completely overridden by your replacement method.

> On Thursday, 25 June 2015 at 03:49:04 UTC, Tofu Ninja wrote:
> > Is this intended or is it a bug?

On Thursday, 25 June 2015 at 03:53:58 UTC, Adam D. Ruppe wrote:
> Intended, the mixin template works on the basis of names. This The extra step is easy though: alias the name in:

I would like to to this with constructors instead of normal methods. I have tried to mix in a constructor as follows:

    #!/usr/bin/rdmd

    import std.stdio;

    mixin template MyConstructor() {
        this(int x, float y) { writefln("%d, %f", x, y); }
    }

    class Base {
        mixin MyConstructor my_ctor;
        this(string s) { writefln(s); }
        alias my_ctor this;
    }

    void main()
    {
        Base b = new Base(3, 4.5);
    }

$ ./mixinctor.d
./mixinctor.d(17): Error: constructor mixinctor.Base.this (string s) is not callable using argument types (int, double)
Failed: ["dmd", "-v", "-o-", "./mixinctor.d", "-I."]

Doing it with
    alias this = my_ctor;
errors out too, and demands me to use alias my_ctor this; as in the original code.

Can I get this to work at all? Or does alias this (for multiple subtyping) fundamentally clash here with alias my_ctor this?

-- Simon