removing arguments as a keyword -- we can detect its use at code-generation time.

lib/coffee_script/grammar.y

@@ -13,7 +13,6 @@ token FOR IN OF BY WHEN WHILE
 token SWITCH LEADING_WHEN
 token DELETE INSTANCEOF TYPEOF
 token SUPER EXTENDS
-token ARGUMENTS
 token NEWLINE
 token COMMENT
 token JS
@@ -102,7 +101,6 @@ rule
   | REGEX                             { result = LiteralNode.new(val[0]) }
   | BREAK                             { result = LiteralNode.new(val[0]) }
   | CONTINUE                          { result = LiteralNode.new(val[0]) }
-  | ARGUMENTS                         { result = LiteralNode.new(val[0]) }
   | TRUE                              { result = LiteralNode.new(Value.new(true)) }
   | FALSE                             { result = LiteralNode.new(Value.new(false)) }
   | YES                               { result = LiteralNode.new(Value.new(true)) }

lib/coffee_script/lexer.rb

@@ -15,8 +15,7 @@ module CoffeeScript
                   "for", "in", "of", "by", "where", "while",
                   "delete", "instanceof", "typeof",
                   "switch", "when",
-                  "super", "extends",
-                  "arguments"]
+                  "super", "extends"]
 
     # Token matching regexes.
     IDENTIFIER = /\A([a-zA-Z$_](\w|\$)*)/

lib/coffee_script/nodes.rb

@@ -153,7 +153,7 @@ module CoffeeScript
     # at the top.
     def compile_with_declarations(o={})
       code  = compile_node(o)
-      args  = self.contains? {|n| n.is_a?(LiteralNode) && n.arguments? }
+      args  = self.contains? {|n| n.is_a?(ValueNode) && n.arguments? }
       argv  = args && o[:scope].check('arguments') ? '' : 'var '
       code  = "#{idt}#{argv}arguments = Array.prototype.slice.call(arguments, 0);\n#{code}" if args
       code  = "#{idt}var #{o[:scope].compiled_assignments};\n#{code}" if o[:scope].assignments?(self)
@@ -203,10 +203,6 @@ module CoffeeScript
     end
     alias_method :statement_only?, :statement?
 
-    def arguments?
-      @value.to_s == 'arguments'
-    end
-
     def compile_node(o)
       indent = statement? ? idt : ''
       ending = statement? ? ';' : ''
@@ -361,6 +357,10 @@ module CoffeeScript
       properties? && @properties.last.is_a?(SliceNode)
     end
 
+    def arguments?
+      @base.to_s == 'arguments'
+    end
+
     def unwrap
       @properties.empty? ? @base : self
     end

lib/coffee_script/rewriter.rb

@@ -22,9 +22,9 @@ module CoffeeScript
     IMPLICIT_FUNC = [:IDENTIFIER, :SUPER, ')', :CALL_END, ']', :INDEX_END]
     IMPLICIT_END  = [:IF, :UNLESS, :FOR, :WHILE, "\n", :OUTDENT]
     IMPLICIT_CALL = [:IDENTIFIER, :NUMBER, :STRING, :JS, :REGEX, :NEW, :PARAM_START,
-                     :TRY, :DELETE, :TYPEOF, :SWITCH, :ARGUMENTS,
+                     :TRY, :DELETE, :TYPEOF, :SWITCH,
                      :TRUE, :FALSE, :YES, :NO, :ON, :OFF, '!', '!!', :NOT,
-                     '->', '=>', '[', '(', '{']
+                     '@', '->', '=>', '[', '(', '{']
 
     # The inverse mappings of token pairs we're trying to fix up.
     INVERSES = BALANCED_PAIRS.inject({}) do |memo, pair|

test/fixtures/execution/test_arguments.coffee

@@ -30,3 +30,8 @@ func: ->
   arguments
 
 print func(100) is 25
+
+
+# Arguments can be accessed as a property.
+this.arguments: 10
+print @arguments is 10