Read-only tuple or Set has wrong types in typescript/lib/lib.es2016.array.include.d.ts

[alesmenzel]

Bug Report

🔎 Search Terms

tuple, readonly, const, includes

🕗 Version & Regression Information

• This is a crash No
• This changed between versions - always like this from what I tested
• This is the behavior in every version I tried, and I reviewed the FAQ for entries about includes, tuple
• I was unable to test this on prior versions because as const was added in version 4

⏯ Playground Link

Playground link with relevant code

💻 Code

const X = ['foo', 'bar'] as const

X.includes('baz')
// Argument of type '"baz"' is not assignable to parameter of type '"foo" | "bar"'.(2345)
// .includes() checks whether a given item is in the tuple, so disallowing any other elements makes the .includes() function useless since all calls that satisfies the types would return true

🙁 Actual behavior

We cannot check whether elements are included in a read-only tuple.

🙂 Expected behavior

We can check whether elements are not included in a read-only tuple.

[MartinJohns]

Duplicate of #14520.

[alesmenzel]

Actually there is even better example

const set = new Set(['foo', 'bar'] as const)
set.has('baz')
// Argument of type '"baz"' is not assignable to parameter of type '"foo" | "bar"'.(2345)

Playground

[MartinJohns]

Still a duplicate of the linked issue. :-)

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.