fixing bug with mixed dot and soak accessors

lib/coffee_script/nodes.rb

@@ -386,7 +386,9 @@ module CoffeeScript
             parts[-1] << "#{SOAK}#{baseline += prop.compile(o)}"
           end
         else
-          parts << prop.compile(o)
+          part = prop.compile(o)
+          baseline += part
+          parts << part
         end
       end
       @last = parts.last

test/fixtures/execution/test_existence.coffee

@@ -41,6 +41,8 @@ obj: {
 
 print obj?.prop is "hello"
 
+print obj.prop?.length is 5
+
 print obj?.prop?.non?.existent?.property is undefined