diff --git a/kernel/bootstrap/hash.rb b/kernel/bootstrap/hash.rb
index ca1a696..0ee3fd5 100644
--- a/kernel/bootstrap/hash.rb
+++ b/kernel/bootstrap/hash.rb
@@ -106,7 +106,7 @@ class Hash

   # Creates a fully-formed instance of Hash.
   #--
-  # @size is the number of pairs, equivalent to <code>hsh.size</code>.
+  # @count is the number of pairs, equivalent to <code>hsh.count</code>.
   # @records is the number of entries in +@bins+.
   # @bins is the vector of storage for the bucket chains.
   #++
@@ -122,7 +122,7 @@ class Hash
     # We don't need the nanny checking our symbols
     set_instance_variable :@records, MIN_SIZE
     set_instance_variable :@bins, Tuple.new(MIN_SIZE)
-    set_instance_variable :@size, 0
+    set_instance_variable :@count, 0
   end

   # Returns the storage vector for Hash. The object should provide
@@ -131,17 +131,21 @@ class Hash
     @bins
   end

-  # Returns the size of the storage vector (+@bins+).
+  # Returns the magnitude of the storage vector (+@bins+).
   def records
     @records
   end

-  def size
-    @size
+  # Retuns the number of items in the Hash.
+  def count
+    @count
   end

-  def size=(size)
-    @size = size
+  # Increments the number of items in the Hash and requests
+  # that the Hash be redistributed. The request will be
+  # honored if the Hash's density exceeds a threshold.
+  def count=(count)
+    @count = count
     redistribute false
   end

@@ -167,9 +171,9 @@ class Hash
     entry = @bins[bin]
     return entry if entry

-    self.size += 1
+    self.count += 1

-    # recalc the bin since #size may have invoked redistribute
+    # recalc the bin since #count may have invoked redistribute
     @bins[entry_bin(key_hash)] = Bucket.new key, nil, key_hash
   end

@@ -183,7 +187,7 @@ class Hash
   # Iterator instance will be invalid after a call to redistribute.
   # If +rehash+ is true, recalculate the key_hash for each key.
   def redistribute(rehash = true)
-    resize = @size >= MAX_DENSITY * @records
+    resize = @count >= MAX_DENSITY * @records
     return unless rehash or resize

     i = to_iter
diff --git a/kernel/common/hash.rb b/kernel/common/hash.rb
index baec56f..45bca28 100644
--- a/kernel/common/hash.rb
+++ b/kernel/common/hash.rb
@@ -56,7 +56,7 @@ class Hash

     # Pickaxe claims that defaults are compared, but MRI 1.8.[46] doesn't actually do that
     # return false unless other.default == default
-    each { |k, v| return false unless other[k] == v }
+    each_item { |k, v| return false unless other[k] == v }
     true
   end

@@ -92,7 +92,7 @@ class Hash

     hsh = key_hash key
     entry = self.entry key, hsh
-    self.size += 1 if entry.set(key, value, hsh)
+    self.count += 1 if entry.set(key, value, hsh)

     value
   end
@@ -140,7 +140,7 @@ class Hash

       bins[bin] = entry.next if result.nil?
       unless result
-        self.size -= 1
+        self.count -= 1
         return entry.value
       end
     end
@@ -149,8 +149,6 @@ class Hash
   end

   def delete_if(&block)
-    raise LocalJumpError, "no block given" unless block_given? or empty?
-
     select(&block).each { |k, v| delete k }

     self
@@ -164,29 +162,24 @@ class Hash
   end

   def each_key
-    raise LocalJumpError, "no block given" unless block_given? or empty?
-
-    each { |k, v| yield k }
+    each_item { |k, v| yield k }

     self
   end

   def each
-    raise LocalJumpError, "no block given" unless block_given? or empty?
-
-    i = to_iter
-    while entry = i.next
-      begin
-        yield [entry.key, entry.value]
-      end while entry = entry.next
-    end
+    each_item { |k, v| yield [k, v] }

     self
   end

-  def each_pair
-    raise LocalJumpError, "no block given" unless block_given? or empty?
-
+  # Yields key, value for each item in the Hash. This method
+  # is necessary to protect the essential iterator from subclasses
+  # (e.g. REXML::Attribute) that replace #each with a version
+  # that is incompatible with the dependencies here (e.g. defining
+  # #each -> #each_attribute -> #each_value, where we had been
+  # defining #each_value in terms of #each).
+  def each_item
     i = to_iter
     while entry = i.next
       begin
@@ -197,20 +190,22 @@ class Hash
     self
   end

-  def each_value
-    raise LocalJumpError, "no block given" unless block_given? or empty?
+  alias_method :each_pair, :each_item

-    each { |k, v| yield v }
+ def each_value
+    each_item { |k, v| yield v }

     self
   end

+  # Returns +size+ == 0. Does not use #count so that a subclass's
+  # idea of size will be consistent with emptiness.
   def empty?
     size == 0
   end

   def index(value)
-    each { |k, v| return k if v == value }
+    each_item { |k, v| return k if v == value }
     nil
   end

@@ -220,7 +215,7 @@ class Hash

     out = []
     RecursionGuard.inspect(self) do
-      each do |key, value|
+      each_item do |key, value|
         str =  key.inspect
         str << '=>'
         str << value.inspect
@@ -233,7 +228,7 @@ class Hash

   def invert
     inverted = {}
-    each { |key, value| inverted[value] = key }
+    each_item { |key, value| inverted[value] = key }
     inverted
   end

@@ -261,7 +256,7 @@ class Hash

   def merge!(other)
     other = Type.coerce_to other, Hash, :to_hash
-    other.each do |k, v|
+    other.each_item do |k, v|
       if block_given? and key? k
         self[k] = yield k, self[k], v
       else
@@ -281,8 +276,6 @@ class Hash
   end

   def reject!
-    raise LocalJumpError, "no block given" unless block_given? or empty?
-
     rejected = select { |k, v| yield k, v }
     return if rejected.empty?

@@ -295,7 +288,7 @@ class Hash
     return self if self.equal? other

     clear
-    other.each { |k, v| self[k] = v }
+    other.each_item { |k, v| self[k] = v }

     if other.default_proc
       @default = other.default_proc
@@ -309,8 +302,6 @@ class Hash
   end

   def select
-    raise LocalJumpError, "no block given" unless block_given? or empty?
-
     selected = []
     i = to_iter
     while e = i.next
@@ -328,12 +319,13 @@ class Hash
     i = to_iter
     if entry = i.next
       bins[i.index] = entry.next
-      self.size -= 1
+      self.count -= 1
       return entry.key, entry.value
     end
   end

-  alias_method :length, :size
+  alias_method :length, :count
+  alias_method :size,   :count

   def sort(&block)
     to_a.sort(&block)
@@ -352,7 +344,7 @@ class Hash
   end

   def value?(value)
-    each { |k, v| return true if v == value }
+    each_item { |k, v| return true if v == value }
     false
   end
   alias_method :has_value?, :value?
diff --git a/kernel/common/misc.rb b/kernel/common/misc.rb
index 926133d..07cee07 100644
--- a/kernel/common/misc.rb
+++ b/kernel/common/misc.rb
@@ -38,7 +38,7 @@ class NilClass
   alias_method :|, :^

   def call(*a)
-    raise LocalJumpError, "not callable"
+    raise LocalJumpError, "no block given or not callable"
   end
 end