If you want arbitrarily complex type-checking, why not just check the property you want at runtime instead using an esoteric typelevel programming language? The

If you want arbitrarily complex type-checking, why not just check the property you want at runtime instead using an esoteric typelevel programming language? The whole point of having types in the first place is provable decidability, not universal computation -- that's what the value-level is designed to do.