`[].slice || ...` generates broken code

[jbt]

Looks like [].slice || (...anything) gets replaced with emptystring.

For example: [].slice||1; 1 becomes ,1 (link)

A less contrived example: var slice = [].slice || function() {...}, somethingElse = 1; becomes var slice=,somethingElse=1 (link)

Seems to happen with .slice and other array methods like indexOf, but not for any old property (i.e. [].foo is fine)

[Rich-Harris]

Released 0.4 with the fix, thanks