Method insert

core/src/compiler/ids.rs:66–81

Inserts the `key`/`value` pair into the hash map, assigning a new identifier to the `key` if it does not yet have one. If the `key` is already present, returns a pair with the previous value and the already assigned identifier. If the `keys` is not yet present, returns a pair with None and the newly-assigned identifier. Returns `None` when the IDs run out.

(&mut self, key: K, value: V)

    ///
    /// Returns `None` when the IDs run out.
    pub(super) fn insert(&mut self, key: K, value: V) -> Option<(Option<V>, I)> {
        let id = match self.map.get(&key) {
            Some((_value, id)) => *id,
            None => match I::try_from(self.map.len()) {
                Ok(id) => id,
                Err(_) => return None,
            },
        };
        self.map
            .insert(key, (value, id))
            .map(|(prev_value, prev_id)| {
                debug_assert_eq!(prev_id, id);
                (Some(prev_value), id)
            })
            .or(Some((None, id)))
    }

    /// Returns the number of assigned identifiers.
    pub(super) fn len(&self) -> usize {