Determine immutability for const type parameters

[bjb568]

Suggestion

Example:

(<const T>(f: () => T) => f)(() => ({ foo: 1 }));

Currently this results in: Return type should have an immutability of at least "Immutable" (actual: "Mutable"). However, the type parameter uses the const keyword so the code is equivalent to the following, which is correctly treated as immutable.

(<T>(f: () => T) => f)(() => ({ foo: 1 } as const));

(Not sure if this is a suggestion for this repo or for is-immutable-type so I made it here.)

[RebeccaStevens]

It seems to be an upstream issue in ts-api-utils. I've created an issue over there, I'll close this one.