}
			return i
		}
	}
	panic(fmt.Sprintf("can't find field in expr %v\n", n))

	// TODO: keep the result of this function somewhere in the ODOT Node
	// so we don't have to recompute it each time we need it.
}

// ssafn holds frontend information about a function that the backend is processing.
// It also exports a bunch of compiler services for the ssa backend.
type ssafn struct {