interface IFoo
{
   void foo();
}

class Foo : IFoo
{
   void bar() {}
   alias bar foo;
}
// class iface_alias.Foo interface function IFoo.foo isn't implemented

This is a problem for me because I want to implement methods with a template, but my choices for that template are a string mixin or a template mixin, and with a template mixin, I have to alias the template to the desired method.

String mixins don't work for this; for example, if the return type is a templated class, string mixins will fail (see #1748). Or if the return type is a public alias to a private type. I'm not aware of a workaround for this (anything that requires manual coding aside from the template is not a valid workaround).