+ /*
+ * For non-optional choices, add a reverse dependency (corresponding to
+ * a select) of '<visibility> && m'. This prevents the user from
+ * setting the choice mode to 'n' when the choice is visible.
+ *
+ * This would also work for non-choice symbols, but only non-optional
+ * choices clear SYMBOL_OPTIONAL as of writing. Choices are implemented
+ * as a type of symbol.
+ */