weird.ts

// everything works totally correctly with this version
export function test<
  P extends Props
>(input: unknown, innerCodec: TypeC<P>) {
  return innerCodec.is(input) // no errors
}

// no errors within this function, but where the function is called such as
//
// test({}, someCodec)
// type { [x: string]: any } is missing the following properties from type '{ id: number; completed_at: string | null; }': id, completed_at [2345]
export function test<
  P extends Props,
  InnerCodec extends TypeC<P>, // <- use a named type to make it easier to read
>(input: unknown, innerCodec: InnerCodec) {
  return innerCodec.is(input)
}

// no errors within this function, but where the function is called such as
//
// test({}, someCodec)
// type { [x: string]: any } is missing the following properties from type '{ id: number; completed_at: string | null; }': id, completed_at [2345]
export function test<
  P extends Props,
  InnerCodec extends TypeC<P> = TypeC<P>, // <- use a named type to make it easier to read
>(input: unknown, innerCodec: InnerCodec) {
  return innerCodec.is(input)
}