X-Git-Url: http://nitlanguage.org

diff --git a/lib/core/collection/abstract_collection.nit b/lib/core/collection/abstract_collection.nit
index 5f9af05..5ed911f 100644
--- a/lib/core/collection/abstract_collection.nit
+++ b/lib/core/collection/abstract_collection.nit
@@ -149,6 +149,12 @@ interface Collection[E]
 	# It is memory-efficient but relies on `has` so may be CPU-inefficient for some kind of collections.
 	fun has_all(other: Collection[nullable Object]): Bool
 	do
+		if is_same_instance(other) then return true
+		var ol = other.length
+		var  l = length
+		if ol == 0 then return true
+		if l == 0 then return false
+		if ol == 1 then return has(other.first)
 		for x in other do if not has(x) then return false
 		return true
 	end
@@ -451,7 +457,9 @@ interface Set[E]
 		var res = 23 + length
 		# Note: the order of the elements must not change the hash value.
 		# So, unlike usual hash functions, the accumulator is not combined with itself.
-		for e in self do res += e.hash
+		for e in self do
+			if e != null then res += e.hash
+		end
 		return res
 	end
 
@@ -680,19 +688,17 @@ interface Map[K, V]
 	# Add each (key,value) of `map` into `self`.
 	# If a same key exists in `map` and `self`, then the value in self is discarded.
 	#
-	# It is the analogous of `SimpleCollection::add_all`
-	#
 	#     var x = new HashMap[String, Int]
 	#     x["four"] = 4
 	#     x["five"] = 5
 	#     var y = new HashMap[String, Int]
 	#     y["four"] = 40
 	#     y["nine"] = 90
-	#     x.recover_with y
+	#     x.add_all y
 	#     assert x["four"]  == 40
 	#     assert x["five"]  == 5
 	#     assert x["nine"]  == 90
-	fun recover_with(map: MapRead[K, V])
+	fun add_all(map: MapRead[K, V])
 	do
 		var i = map.iterator
 		while i.is_ok do
@@ -701,6 +707,9 @@ interface Map[K, V]
 		end
 	end
 
+	# Alias for `add_all`
+	fun recover_with(map: MapRead[K, V]) is deprecated do add_all(map)
+
 	# Remove all items
 	#
 	#     var x = new HashMap[String, Int]
@@ -1156,6 +1165,30 @@ interface Sequence[E]
 	#
 	# REQUIRE `index >= 0 and index < length`
 	fun remove_at(index: Int) is abstract
+
+	# Rotates the elements of self once to the left
+	#
+	# ~~~nit
+	# var a = [12, 23, 34, 45]
+	# a.rotate_left
+	# assert a == [23, 34, 45, 12]
+	# ~~~
+	fun rotate_left do
+		var fst = shift
+		push fst
+	end
+
+	# Rotates the elements of self once to the right
+	#
+	# ~~~nit
+	# var a = [12, 23, 34, 45]
+	# a.rotate_right
+	# assert a == [45, 12, 23, 34]
+	# ~~~
+	fun rotate_right do
+		var lst = pop
+		unshift lst
+	end
 end
 
 # Iterators on indexed collections.