The soon-to-be-released GHC 7.8 (Haskell) can defer type errors until runtime to allow you run your program even if part of it is broken, and you can also add "holes" in place of an arbitrary expression and the compiler will tell you the type of the expression you need to replace it with (of course, this will explode if run). I suspect GHC's error messages are better than Ocaml's as well.