ReadonlyDeep / WritableDeep not modifying arrays as of TS 5.3.3

[trevorade]

See a repro of the issue for ReadonlyDeep in this TS Playground (change the version to 5.2.2 to see the older correct behavior)

This is verified in the test here (though failing to fail as it should):

type-fest/test-d/readonly-deep.ts

Line 105 in 67f90a3

expectType<readonly boolean[]>(readonlyData.namespace.baz);

WritableDeep exhibits the same issue.

I suspect that the typing system is behaving differently in tsd than the raw tsc leading to this issue not being detected. Not sure why...

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[gloomweaver]

The issue here is HasMultipleCallSignatures
In 5.2.2 it returned false for Namespace, in current it returns true
You can actually break it 5.2.2 if you provide additional signature in the type

Tried this
HasMultipleCallSignatures<T> extends true ? T & ReadonlyObjectDeep<T> : ((...arguments_: Parameters<T>) => ReturnType<T>) & ReadonlyObjectDeep<T>
But then type of baz is boolean[] & readonly boolean[]
Didn't find a way to pick only signatures from T

[voxpelli]

@trevorade I think the issue is that this repo is using an outdated version of tsd and since tsd ships with its own version of typescript this isn't discovered by it. When updating tsd it does error on this: #839

Hence why we probably should move away from tsd as we talked about in #837

[mrazauskas]

I was looking at the issue with ReadonlyDeep. Bisecting tells that the first bad commit is microsoft/TypeScript#54448. Hope that helps.