Merge pull request #418 from amatsuda/warnings

Ruby warnings

Author: jdantonio

lib/concurrent/atom.rb

@@ -61,7 +61,7 @@ class Atom < Synchronization::Object
     include Concern::Observable
 
     safe_initialization!
-    private *attr_volatile_with_cas(:value)
+    private(*attr_volatile_with_cas(:value))
     public :value
 
     # Create a new atom with the given initial value.

lib/concurrent/synchronization/object.rb

@@ -79,7 +79,7 @@ def self.new(*)
       end
 
       def self.safe_initialization?
-        @safe_initialization || (superclass.respond_to?(:safe_initialization?) && superclass.safe_initialization?)
+        (defined?(@safe_initialization) && @safe_initialization) || (superclass.respond_to?(:safe_initialization?) && superclass.safe_initialization?)
       end
 
       # For testing purposes, quite slow.
@@ -122,7 +122,7 @@ def compare_and_set_#{name}(expected, value)
             end
 
             def update_#{name}(&block)
-              #{ivar}.update &block
+              #{ivar}.update(&block)
             end
           RUBY
         end