Re: class is forward referenced when looking for 'v'

[Kenji Hara via Digitalmars-d-learn]

On Friday, 30 January 2015 at 00:09:17 UTC, Amber Thralll wrote:
And the errors dmd returns:
test.d(16): Error: class test.A!int.A is forward referenced 
when looking for 'v'
test.d(16): Error: class test.A!int.A is forward referenced 
when looking for 'opDot'
test.d(16): Error: class test.A!int.A is forward referenced 
when looking for 'opDispatch'
test.d(29): Error: no property 'v' for type 'test.A!int.A'
test.d(10): Error: template instance test.B!int error 
instantiating
test.d(16):        instantiated from here: Base!int
test.d(35):        instantiated from here: A!int
Is this a bug in D?  Or am I doing something wrong?

In D, forward reference resolution should have consistent result 
for template classes and non-template ones. If the code is 
rewritten to non-template version:

import std.stdio;

class Base
{
    public void Foo(A a)
    {
        writeln("Base.Foo(A a)");
    }

    public void Foo(B a)
    {
        writeln("Base.Foo(B a)");
    }
};

class A : Base
{
    public int v;
    this(int v)
    {
        this.v = v;
    }
}

class B : Base
{
    public override void Foo(A a)
    {
        writeln("A: ", a.v);
    }
}

int main()
{
    A a = new A(1);
    B b = new B();

    a.Foo(b);
    b.Foo(a);

    return 0;
}

Compiler properly resolves forward references. Therefore, it's 
definitely a compiler bug, and the template version should be 
accepted.

I filed the issue in bugzilla:
https://issues.dlang.org/show_bug.cgi?id=14083

And will open a new pull request to fix compiler.

Kenji Hara