Crash from tricky generics

[tomblind]

I was playing with generics and managed to crash TSTL. Here's my attempt at boiling it down to an isolated repro:

type Foo<A extends unknown[]> = (fn: (...args: A) => void) => void;

export function bar<A extends Foo<[]>[]>(...args: A) {
    type X = A extends Foo<infer T>[] ? Foo<T[]> : never;
    return (fn => {}) as X;
}

And here's the error:

TypeError: Cannot read property 'kind' of undefined
    at Object.parenthesizeArrayTypeMember (node_modules/typescript-to-lua/node_modules/typescript/lib/typescript.js:74192:24)
    at Object.createArrayTypeNode (node_modules/typescript-to-lua/node_modules/typescript/lib/typescript.js:70459:31)
    at typeReferenceToTypeNode (node_modules/typescript-to-lua/node_modules/typescript/lib/typescript.js:38969:44)
    at typeToTypeNodeHelper (node_modules/typescript-to-lua/node_modules/typescript/lib/typescript.js:38766:95)
    at serializeTypeForDeclaration (node_modules/typescript-to-lua/node_modules/typescript/lib/typescript.js:39870:30)
    at symbolToParameterDeclaration (node_modules/typescript-to-lua/node_modules/typescript/lib/typescript.js:39357:41)
    at node_modules/typescript-to-lua/node_modules/typescript/lib/typescript.js:39305:101
    at Array.map (<anonymous>)
    at signatureToSignatureDeclarationHelper (node_modules/typescript-to-lua/node_modules/typescript/lib/typescript.js:39305:67)
    at createTypeNodeFromObjectType (node_modules/typescript-to-lua/node_modules/typescript/lib/typescript.js:38944:49)

Normal TS doesn't seem to have a problem with it, so it's TSTL-specific.

[tomblind]

Additional info:
Tracing into TS leads to a return statement generating the offending undefined value with a comment that points to this issue: microsoft/TypeScript#18217
The offending line is here: https://github.dev/microsoft/TypeScript/blob/main/src/compiler/checker.ts#L5095

[tomblind]

Minimalist repro:

type Foo = (fn: (...args: [][]) => void) => void;
const foo: Foo = (bar => {});

It appears to be triggered by the vararg type of empty tuples (...args: [][]). The error occurs calling typeToTypeNode on the the type of the initializer (bar => {}).

Error:

Exception has occurred: TypeError: Cannot read property 'kind' of undefined
  at Object.parenthesizeElementTypeOfArrayType (node_modules\typescript\lib\typescript.js:20825:28)
    at Object.createArrayTypeNode (node_modules\typescript\lib\typescript.js:22343:53)
    at typeReferenceToTypeNode (node_modules\typescript\lib\typescript.js:49344:52)
    at typeToTypeNodeHelper (node_modules\typescript\lib\typescript.js:49085:95)
    at serializeTypeForDeclaration (node_modules\typescript\lib\typescript.js:50323:30)
    at symbolToParameterDeclaration (node_modules\typescript\lib\typescript.js:49803:41)
    at node_modules\typescript\lib\typescript.js:49725:263
    at Array.map (<anonymous>)
    at signatureToSignatureDeclarationHelper (node_modules\typescript\lib\typescript.js:49725:229)
    at createTypeNodeFromObjectType (node_modules\typescript\lib\typescript.js:49296:49)

[tomblind]

TS Issue

[Perryvw]

No longer reproduces