Allowing both end-points of slices to be implicit.

lib/coffee-script/grammar.js

@@ -291,6 +291,8 @@
         return new Range($1, null, $2);
       }), o('RangeDots Expression', function() {
         return new Range(null, $2, $1);
+      }), o('RangeDots', function() {
+        return new Range(null, null, $1);
       })
     ],
     ArgList: [

src/grammar.coffee

@@ -343,6 +343,7 @@ grammar =
     o 'Expression RangeDots Expression',        -> new Range $1, $3, $2
     o 'Expression RangeDots',                   -> new Range $1, null, $2
     o 'RangeDots Expression',                   -> new Range null, $2, $1
+    o 'RangeDots',                              -> new Range null, null, $1
   ]
 
   # The **ArgList** is both the list of objects passed into a function call,

test/slicing_and_splicing.coffee

@@ -39,6 +39,8 @@ test "unbounded slicing", ->
   for a in [-shared.length+1...shared.length]
     arrayEq shared[..a][...-1] , shared[...a]
 
+  arrayEq [1, 2, 3], [1, 2, 3][..]
+
 test "#930, #835, #831, #746 #624: inclusive slices to -1 should slice to end", ->
   arrayEq shared, shared[0..-1]
   arrayEq shared, shared[..-1]
@@ -79,6 +81,9 @@ test "unbounded splicing", ->
   ary[...3] = [7, 8, 9]
   arrayEq [7, 8, 9, 9, 8, 7], ary
 
+  ary[..] = [1, 2, 3]
+  arrayEq [1, 2, 3], ary
+
 test "splicing with variables as endpoints", ->
   [a, b] = [1, 8]