• via Digitalmars-d-bugs (64/64) Jan 30 2015 https://issues.dlang.org/show_bug.cgi?id=14083

via Digitalmars-d-bugs <digitalmars-d-bugs puremagic.com> writes:

https://issues.dlang.org/show_bug.cgi?id=14083

          Issue ID: 14083
           Summary: Remained unresolved forward reference issue with
                    template classes
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Keywords: rejects-valid
          Severity: normal
          Priority: P1
         Component: DMD
          Assignee: nobody puremagic.com
          Reporter: k.hara.pg gmail.com

From: http://forum.dlang.org/thread/rggurpzmskjxesfelnwv forum.dlang.org

Following code should work, but doesn't.

import std.stdio;

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

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

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

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

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

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

    return 0;
}

Output:

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

--