To expand, with regard to (GHC) Haskell: you can perform run-time type checks with the Typeable typeclass, and you can forgo compile-time checks in favor of run

To expand, with regard to (GHC) Haskell: you can perform run-time type checks with the Typeable typeclass, and you can forgo compile-time checks in favor of runtime checks with Data.Dynamic. You can also replace compile-time detected type errors with "if this is executed, explode", with the -fdefer-type-errors flag. And of course, in any typed language you can apply sufficiently general types that you need to perform manual checks for safety.