r/outId/oi/ ?

testcase:
```d
class A
{
    int foo()
    out (r1) { }
    body { return 1; }
}

class B : A
{
    override int foo()  // line 11
    out (r2) { }
    body { return 1; }
}

class C : B
{
    override int foo()
    out (r3) { }
    body { return 1; }
}

class D : C
{
    override int foo()
    out (r4) { }
    body { return 1; }
}
```

output:
```
test.d(11): Error: undefined identifier r3, did you mean variable r4?
```