+#[stable(feature = "std_collections_from_array", since = "1.56.0")]
+// Note: as what is currently the most convenient built-in way to construct
+// a HashMap, a simple usage of this function must not *require* the user
+// to provide a type annotation in order to infer the third type parameter
+// (the hasher parameter, conventionally "S").
+// To that end, this impl is defined using RandomState as the concrete
+// type of S, rather than being generic over `S: BuildHasher + Default`.
+// It is expected that users who want to specify a hasher will manually use
+// `with_capacity_and_hasher`.
+// If type parameter defaults worked on impls, and if type parameter
+// defaults could be mixed with const generics, then perhaps
+// this could be generalized.
+// See also the equivalent impl on HashSet.
+impl<K, V, const N: usize> From<[(K, V); N]> for HashMap<K, V, RandomState>
+where
+ K: Eq + Hash,
+{
+ /// # Examples
+ ///
+ /// ```
+ /// use std::collections::HashMap;
+ ///
+ /// let map1 = HashMap::from([(1, 2), (3, 4)]);
+ /// let map2: HashMap<_, _> = [(1, 2), (3, 4)].into();
+ /// assert_eq!(map1, map2);
+ /// ```
+ fn from(arr: [(K, V); N]) -> Self {
+ crate::array::IntoIter::new(arr).collect()
+ }
+}
+