Fail on single line lambda with semicolon

[refack]

decaffeinate is producing the wrong JavaScript based on my CoffeeScript input:

foo = () -> null for i in []; t

(repl)

I get this output:

let foo = () => [].map((i) => (null, t));

Here's what I expect it to be instead:
preferably:

let foo = () => {[].map((i) => null); return t}

else at least as if it's a multiline function

let foo = function() { 
  for (let i of []) { null; }
  return t;
};

[alangpierce]

Thanks for reporting. Looks like the bug is that the normalize step rewrites it as this:

foo = () -> for i in [] then null; t

But I guess it needs to maintain the precedence, maybe by wrapping the loop in parens:

foo = () -> (for i in [] then null); t

[refack]

LGTM
👍