Update tsd (and pin TypeScript to current minor)

[voxpelli]

As a preparation for #837 and as a companion to #838 I went ahead an updated tsd as well to the latest version, but turns out that the tsd tests are broken in latest version (likewise broken when rewriting to use eg. expect-type in latest typescript)

Fixes #833

[mrazauskas]

As far as I can understand, there are two failures here:

1. As already mentioned in ReadonlyDeep / WritableDeep not modifying arrays as of TS 5.3.3 #833 (comment), tests of ReadonlyDeep / WritableDeep are failing because of a change in TypeScript Improve inference between types with multiple signatures microsoft/TypeScript#54448

2. The failure of MergeDeep test is a bug / feature of tsd (triggered by some another change in TypeScript).

   There are numerous issues in tsd repo pointing out that types are getting inferred different, if an expression is moved outside of an assertion. In this case, type of the source argument passed to mergeDeep() is inferred by tsd assertion as (number | true)[]:

   

   , but outside of assertion it is inferred as (number | boolean)[]:

   

   This difference if cause by the fact that tsd is inferring types already knowing what result is expected. More or less like here (and this can be interpreted both as a bug or a feature):

   

I guess you saw similar issues before and this is why expect-type got involved. The following assertion is passing:

expectTypeOf(mergeDeep(['life'], [42, true], {arrayMergeMode: 'spread'})).toEqualTypeOf<Array<number | string | boolean>>();

, because type is inferred correctly (in mine and expect-types opinion):

[voxpelli]

Seems like the issue was HasMultipleCallSignatures, it always returned true, but I made a fix for that

[voxpelli]

Needs one fix

[voxpelli]

Now it properly detects a multiple signature like this as well:

type Overloaded2 = {
	(foo: number | undefined): string;
	(foo: number): string;
};

[sindresorhus]

Would you be able to add a test to test-d/writable-deep.ts too? So it doesn't regress again in the future.

[voxpelli]

@sindresorhus Sure, there is a test already, but most tests in both of these are indirect ones which gives some cascading one, I'll add en explicit one 👍

[voxpelli]

@sindresorhus Done ✔️

[sindresorhus]

Great! Thanks 👍👍