error compiling with tsgo

[joprice]

I wanted to see how my project's compilation performs with tsgo, since the latest version is expected to have no differences in type-checking, but it fails to compile due to the error Type 'StaticParamList' is not generic.:

error TS2315: Type 'StaticParamList' is not generic.

979 type RootStackParamList = StaticParamList<typeof RootStack>;

I found a similar issue microsoft/typescript-go#1968 (comment) here, but unsure whether the react-navigation type is relying on undefined behavior or if there's a bug in the new compiler. If there's another way to formulate the type to introduce some laziness avoiding the circular reference so that it compiles in current tsgo, it would be convenient for getting the benefits of tsgo for quick typechecking in a watch loop, even if its other features aren't yet ready.

[satya164]

that looks like tsgo bug, because it's a pretty straighforward generic type so the message doesn't make sense

react-navigation/packages/core/src/StaticNavigation.tsx

Line 471 in 94a70aa

export type StaticParamList<

it's hard to say if there is reliance on undefined behavior since not everything is clearly documented, and it can get pretty complex. i am also not familiar with typescript internals so pull requests are welcome improving the types.

[joprice]

The obscure error only exists in the consuming project. Running it directly on react-navigation shows the underlying reason why the type ends up appearing to have no generics, because it failed at an earlier stage due to a circular reference:

packages/core/src/StaticNavigation.tsx:291:13 - error TS2456: Type alias 'StaticParamList' circularly references itself.

291 export type StaticParamList<

[satya164]

the type needs to be used recursively to be able to recursively traverse through all nested navigators and get the types - it's not like a variable referencing itself in the value, but like a function calling itself recursively, as it's a utility type.

this has been working for years with typescript without any changes, so i'd assume this is a bug in tsgo.

[joprice]

Yea it’s probably eagerly evaluating the type functions in the new version. I brought it up because the claim is that the new compiler is stable with regards to type checking so perhaps it won’t be addressed. I’ll see if the issue gets attention in the next few weeks and open a dedicated one if it doesn’t.