Proposal: 'always' type

[pelotom]

We have a never type representing the bottom of the type lattice... what about having a built-in corresponding "top" type? Essentially:

type always = {} | void | null

A variable of type always can be assigned any value, but nothing is known about it aside from the fact that it exists. any doesn't fit the bill, because we can assign an any to any other type and access arbitrary properties on it (it behaves like both never and always depending on the context).

[RyanCavanaugh]

The suggestion is simply to add that line to lib.d.ts?

[pelotom]

It would be ideal if it was built-in rather than a type alias, so that it didn't get expanded to {} | void | null everywhere, but failing that a type alias in the lib would be fine.

[dead-claudia]

This sounds like a dupe of #10715, just with a different name. unknown there and always here are both top types.

[RyanCavanaugh]

Some elaboration of the desired use of this type would be helpful. What's it for? Why would I use it? What would the documentation say about it?

[pelotom]

@RyanCavanaugh #10715 has a good detailed description of why this is desirable.

[RyanCavanaugh]

Is this a duplicate then?

[pelotom]

Yes, modulo a suggestion of what to call this type.