makeing the method of the compiler more or less private

in preparation for using the same code for bocks

lib/vool/basic_values.rb

@@ -70,7 +70,7 @@ module Vool
       @my_type = type
     end
     def slot_definition(compiler)
-      @my_type = compiler.method.self_type
+      @my_type = compiler.resolve_type(:receiver)
       Mom::SlotDefinition.new(:message , [:receiver])
     end
     def ct_type