om.d

module common;

class A {}
class B : A {}
class C : B {}

void foo(virtual A) {}


// ---

module one;

import common;
import two;

void foo(virtual B) {}
alias foo = common.foo;
// override void foo(virtual C) {} // ambiguous
override void common.foo(virtual C) {} // OK

void bar()
{
    foo(new A); // call common.foo(virtual A)
    foo(new B); // call two.foo(virtual B)
    foo(new C); // call one.foo(virtual C)
}

// ---

module two;

import common;

override void foo(virtual B) {}

void bar()
{
    foo(new C); // will call one.foo(virtual C)
}