pub const MAP: BuiltinSchema;Expand description
Map<K, V>: an immutable mapping, kept in ascending key order.
inserted and removed are past participles because the map they answer
with is a new one; nothing here writes through the receiver, unlike
Vector’s push. Which values may be keys is a runtime rule — a key’s
equality must not be able to change — and stating it here would need
bounds, which the MVP does not have.