Using a default argument inside an array in a function parameters raises an exception

[asdrubalivan]

The following code in Coffeescript 1.8.0 raises an exception

myFn = (x = 2 ,[a = false, b = 3]) ->

This exception is

TypeError: Cannot read property 'length' of undefined
  at Param.exports.Param.Param.eachName (/usr/lib/node_modules/coffee-script/lib/coffee-script/nodes.js:2049:32)
  at Param.exports.Param.Param.eachName (/usr/lib/node_modules/coffee-script/lib/coffee-script/nodes.js:2052:16)
  at Code.exports.Code.Code.eachParamName (/usr/lib/node_modules/coffee-script/lib/coffee-script/nodes.js:1970:29)
  at Code.exports.Code.Code.compileNode (/usr/lib/node_modules/coffee-script/lib/coffee-script/nodes.js:1927:12)
  at Code.exports.Base.Base.compileToFragments (/usr/lib/node_modules/coffee-script/lib/coffee-script/nodes.js:83:21)
  at Assign.exports.Assign.Assign.compileNode (/usr/lib/node_modules/coffee-script/lib/coffee-script/nodes.js:1628:24)
  at Assign.exports.Base.Base.compileToFragments (/usr/lib/node_modules/coffee-script/lib/coffee-script/nodes.js:83:21)
  at Block.exports.Block.Block.compileNode (/usr/lib/node_modules/coffee-script/lib/coffee-script/nodes.js:381:28)
  at Block.exports.Block.Block.compileWithDeclarations (/usr/lib/node_modules/coffee-script/lib/coffee-script/nodes.js:474:19)
  at Block.exports.Block.Block.compileRoot (/usr/lib/node_modules/coffee-script/lib/coffee-script/nodes.js:446:24)
  at Block.exports.Block.Block.compileToFragments (/usr/lib/node_modules/coffee-script/lib/coffee-script/nodes.js:363:21)
  at Object.<anonymous> (/usr/lib/node_modules/coffee-script/lib/coffee-script/coffee-script.js:49:61)
  at Object.compile (/usr/lib/node_modules/coffee-script/lib/coffee-script/coffee-script.js:34:19)
  at compileScript (/usr/lib/node_modules/coffee-script/lib/coffee-script/command.js:216:33)
  at compilePath (/usr/lib/node_modules/coffee-script/lib/coffee-script/command.js:161:14)
  at Object.exports.run (/usr/lib/node_modules/coffee-script/lib/coffee-script/command.js:96:21)
  at Object.<anonymous> (/usr/lib/node_modules/coffee-script/bin/coffee:7:41)
  at Module._compile (module.js:456:26)
  at Object.Module._extensions..js (module.js:474:10)
  at Module.load (module.js:356:32)
  at Function.Module._load (module.js:312:12)
  at Function.Module.runMain (module.js:497:10)
  at startup (node.js:119:16)
  at node.js:906:3

This also happens if I put a true instead of a false in the code above, but this doesn't happen if I just put numbers like

 myFn = (x = 2 ,[a = 1, b = 3]) ->

I know both examples are syntax errors, but the exception raised by the first one was not expected.

[GeoffreyBooth]

This compiles just as it looks in CS2:

var myFn;

myFn = function(x = 2, [a = false, b = 3]) {};