Exhaustive switch return type does not work when wrapped in a try-catch.

[trusktr]

TypeScript Version: 3.4.5

Search Terms:

Exhaustive switch return type does not work when wrapped in a try-catch

Code

enum Foo {
  One,
  Two,
  Three
}

function test(type: Foo): number {
  switch (type) {
    case Foo.One:
      return 0;
    case Foo.Two:
      return 0;
    case Foo.Three:
      return 0;
  }
}

function test2(type: Foo): number { // ERROR
  try {
    switch (type) {
      case Foo.One:
        return 0;
      case Foo.Two:
        return 0;
      case Foo.Three:
        return 0;
    }
  } catch (e) {
      throw new Error('some error')
  }
}

playground

Expected behavior:

It should still work (because clearly in this case it can only return those values, or throw an error).

Actual behavior:

Error

[RyanCavanaugh]

All of the function-always-returning-from-exhaustive-switch forms are special-cased; this one seems like a good additional special case

[jack-williams]

Fix here: #32952.

[jack-williams]

@ahejlsberg fixed this in #32695.

[trusktr]

Looks like fixed, tested in playground. Thanks!