Clear the Enumerator#peek lookahead value on #rewind

kernel/common/enumerator.rb

@@ -158,15 +158,6 @@ def reset
         end
       end
     end
-
-    # Rewinds the enumeration sequence by the next method.
-    #
-    # If the enclosed object responds to a "rewind" method, it is called.
-    #
-    def rewind
-      @generator.rewind if @generator
-      self
-    end
   end
 end
 

kernel/common/enumerator18.rb

@@ -33,5 +33,14 @@ def next
 
       raise StopIteration, "iteration reached end"
     end
+
+    # Rewinds the enumeration sequence by the next method.
+    #
+    # If the enclosed object responds to a "rewind" method, it is called.
+    #
+    def rewind
+      @generator.rewind if @generator
+      self
+    end
   end
 end

kernel/common/enumerator19.rb

@@ -73,6 +73,16 @@ def peek
       item
     end
 
+    # Rewinds the enumeration sequence by the next method.
+    #
+    # If the enclosed object responds to a "rewind" method, it is called.
+    #
+    def rewind
+      @generator.rewind if @generator
+      @lookahead = []
+      self
+    end
+
     # A supporting class for Enumerator that allows for easy proxying to a Generator's yield.
     class Yielder
       def initialize(&block)