Mateusz Burzyński

FWIW, this error is reported [here](https://github.dev/microsoft/TypeScript/blob/d8086f14b6b97c0df34a0cc2f56d4b5926a0c299/src/compiler/checker.ts#L33947-L33955) and this is the [`mergeSymbols` call](https://github.dev/microsoft/TypeScript/blob/d8086f14b6b97c0df34a0cc2f56d4b5926a0c299/src/compiler/checker.ts#L49856) that is responsible for putting the `invalid1` member onto that symbol table. In a sense, this is by...

I'm still working on minimizing this further but I want to share a single-file repro created based on the code from grammy. Some parts of this probably no longer make...

In a sense, this could be seen as a duplicate of https://github.com/microsoft/TypeScript/issues/13948 . Like I mentioned [here](https://github.com/microsoft/TypeScript/pull/54706#discussion_r1234193815) the computed properties like this are always widened - without considering the contextual...

@andrewbranch @sandersn is there anything blocking this from being merged? :)

> The method and results seem decent. I don't really like the code organization -- although there may be a reason for it that I'm missing. @sandersn I addressed this...

@zigcccc could you prepare a repro case of the problem? you could try to remove as much lines from your project as possible (gradually) and bisect the problem this way...

I think that perhaps this *could* work (but it doesn't): ```ts type StructTypeFor = { [K in keyof Descriptor as Descriptor[K][0]]: ValueTypeOf; }; ``` I might play with implementing a...

> A tuple type of a fixed, known length still has a number index signature, and that leads to us mapping over this index signature in a mapped type, and...

> are we okay with this behavior? It's not perfect but it's nothing new ([TS playground](https://www.typescriptlang.org/play/?ts=5.5.2#code/C4TwDgpgBAKgDFAvFA2gMwJYCcDOwBcUeWGAdgOYC6A3ALABQoksAjEqprgVKQK4C2AIwhYANFAB0U+DQYB6OVCUA9APwMgA)) ```ts type T0 = [first: string]; type T1 = [first: number, ...T0]; // ^?...

@jakebailey fixed that :)