Typescript: Function that always throws is not inferred as having `never` return type

[masaeedu]

TypeScript Version: 2.5.0-dev.20170618

Code

function fail1() {
  throw new Error()
}

const fail2 = function () {
  throw new Error()
}

Expected behavior:
Inferred return type of both functions is never

Actual behavior:
Only the return type of the second function is never. The return type of fail1 is inferred as void.

[ahejlsberg]

This is by design. We had it the way you suggest originally but I was too much of a breaking change. See #8767 for more details.

[masaeedu]

@ahejlsberg Could we have an off-by-default compiler flag that unifies this behavior?

[basarat]

Perhaps only class methods should get void inference :rose:

[mhegazy]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.

[aluanhaddad]

I really like @basarat's suggestion.