https://hackage.haskell.org/package/base-4.14.0.0/docs/src/D...
Also notice that Dynamic is in the Haskell Package Repository's "base" package, described as containing "Basic libraries", not part of an ancillary area for user-contributed libraries:
https://hackage.haskell.org/package/base-4.14.0.0
There exist type systems of which great grandparent is an accurate description (the most well-known of which is probably that used by Typescript) but the type system of, e.g., Haskell, Ocaml or Rust is not it.
(Now I am getting curious what specific programming language's type system great grandparent had in mind.)