I think there's a bug somewhere when compiling math operators and using implicit conversion functions. The following test fails.

int x = 1;
class A
{
    int val;
    A(int x)
    {
        val = x;
    }
    int opImplConv()
    {
        return val;
    }
}

A myA(5);

void main()
{
    assert(myA + (x + 1) == myA + x + 1);
}

The error seems to be that after the CALLINTF instruction for A::opImplConv there is no following CpyRtoV4. The error is in the bytecode generated on the left side of the comparison.

Also, if the global declaration of "x" is removed and a local declaration of "x" is added to the main function the bug is gone.