gcc/testsuite/gdc.test/compilable/test19809.d

// https://issues.dlang.org/show_bug.cgi?id=19809
mixin template Impl(M...)
{
    int opCmp(Object o) { return 0; }
}

class C
{
    override
    {
        int function(int) fp = ((int x) => x);
        mixin Impl!("x", "y", ((int x) => x));
    }
}