lib/sass/script/list.rb in sass-3.1.0.alpha.261 vs lib/sass/script/list.rb in sass-3.1.0.alpha.262

@@ -31,10 +31,11 @@
         self.separator == other.separator)
     end
 
     # @see Node#to_s
     def to_s(opts = {})
-      return value.map {|e| e.to_s(opts)}.join(sep_str)
+      raise Sass::SyntaxError.new("() isn't a valid CSS value.") if value.empty?
+      return value.reject {|e| e.is_a?(List) && e.value.empty?}.map {|e| e.to_s(opts)}.join(sep_str)
     end
 
     # @see Node#to_sass
     def to_sass(opts = {})
       precedence = Sass::Script::Parser.precedence_of(separator)