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ZpdDG4gta (zpdDG4gta8XKpMCd)

opened on Aug 26, 2015

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in #3823

interface A {
}
var a : A = { // valid code, but expected a problem in 1.6, since x, y, z don't belong to A 
    x: 1,
    y: 2,
    z: 3
};

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1. danquirk commented on Aug 26, 2015

   

   Dan Quirk (danquirk)

   on Aug 26, 2015

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   Ryan had proposed a rule that would error here if A at least had some optional members, but not if it was empty. I'm not sure what the rationale was for not erroring against empty types as well: #3842
2. Ryan Cavanaugh (RyanCavanaugh)

   added

   By DesignDeprecated - use "Working as Intended" or "Design Limitation" insteadDeprecated - use "Working as Intended" or "Design Limitation" instead

   on Aug 26, 2015
3. RyanCavanaugh commented on Aug 26, 2015

   

   Ryan Cavanaugh (RyanCavanaugh)

   on Aug 26, 2015

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   Lots of people use {} in place of any because they don't want accidental anys creeping in, but still want something that's assignable from anything. Erroring on object literals assigned to {} is kind of pointless because, if we did, there would be nothing valid you could have written -- if you really wanted a type that couldn't be assigned from any non-null/undefined value, void is there.
4. Ryan Cavanaugh (RyanCavanaugh)

   closed this as completedon Aug 26, 2015
5. zpdDG4gta8XKpMCd commented on Aug 26, 2015

   

   ZpdDG4gta (zpdDG4gta8XKpMCd)

   on Aug 26, 2015

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   Are values of void now officially a part of the language? Thought they were leaving.
6. RyanCavanaugh commented on Aug 26, 2015

   

   Ryan Cavanaugh (RyanCavanaugh)

   on Aug 26, 2015

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   The void type isn't going anywhere. The only thing we've been warning people of using the crazy number|void thing to fake non-nullability.
7. zpdDG4gta8XKpMCd commented on Aug 26, 2015

   

   ZpdDG4gta (zpdDG4gta8XKpMCd)

   on Aug 26, 2015

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   Can's say I see your point:

   The void type isn't going anywhere.

   Fine, since it's just a type let's keep it. I was talking about values of type void which sort of don't make sense since void by definition represents a lack of value. The only type that doesn't have a value yet is assignable from null and undefined (what might this mean?).

   warning people of using the crazy number|void thing

   Why would you warn? With all what's above number|void seems 100% legit (void is just another type that, hm, has values, remember?). Although I agree as far as making sense it fails, just like the idea of a legit value of void does.

   thing to fake non-nullability

   Business sees value in it and wants it. I would not call it faking unless proven otherwise. If number|void gives hard feelings how about a memberless enum?

   const enum Nothing {}

   Ugh, Nothing | number don't play nice together, dang, lets go back to void.
8. zpdDG4gta8XKpMCd commented on Aug 26, 2015

   

   ZpdDG4gta (zpdDG4gta8XKpMCd)

   on Aug 26, 2015

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   just thought you guys might be interested https://github.com/aleksey-bykov/by-design-script/blob/master/README.md#literal-strictness
9. microsoft

   locked and limited conversation to collaborators on Jun 19, 2018

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