// assumed to be numeric. Attempts conversion to numeric type for `a`
// (first int, then float) only if the underlying values do not have a
// type.
func (v *Value) minmax(a *Value, isMax, isFirstRow bool) error {
	err := inferTypeForArithOp(a)
	if err != nil {
		return err
	}

	if !a.isNumeric() {
		return errArithMismatchedTypes
	}