interface Reader {
  chunk: unknown;
}
type Parser<R extends Reader = Reader> = <R2 extends R>(reader: R2) => 2;

interface TextReader {
  chunk: string;
}
interface ByteReader {
  chunk: Uint8Array;
}
const byte: Parser<ByteReader> = () => 2;

const test1: Parser<TextReader> = byte;
type TestParser = Parser<TextReader>;
const test2: TestParser = byte;
// @ts-expect-error
const test3: <R2 extends TextReader>(reader: R2) => 2 = byte;