assertFalse: {.noreturn.} alternative to doAssert(false); safer than quit

[timotheecour]

    proc fun(a: string): int =
      case a
      of "foo": 1
      of "bar": 2
      of "bad1":
        doAssert false
        0 ## awkard, it requires specifying an `expr`, eg `default(typeof(result))`
      of "bad2": assertFalse() ## better; {.noreturn.} so no `expr` needed
      else: assertFalse(a)
    doAssertRaises(AssertionError): discard fun("bad")

note

this doesn't have any of the pitfalls of quit, see quit considered evil: bypasses defer and try/catch/finally which might do important cleanups - Nim forum

[Araq]

Maybe this should be called unreachable, but come on, almost nobody asked for this feature in a decade. If we add every little helper you think is nice to have, Nim would have a million of them, slowing down compile-times to the point where you're objectively more productive without them.

[Araq]

Cannot find a scenario where I am willing to accept this addition, so closing.