The Snap framework (http://snapframework.com/) for Haskell works this way. Your application (including the web server itself) gets compiled down to a single binary, but during development you can make changes and see them reflected on the fly without manually recompiling. This is my understanding based on an interview with one of the framework's developers; I haven't used it myself for any significant project, though I plan to.

Haskell in general meets a lot (though probably not all) of the author's requirements. Static type inference is great, and Haskell's system makes explicit type declarations completely optional except for in a handful of rare cases, though you will find yourself wanting to use them on most functions anyway because of how they clarify and improve the readability of your code. Testing is also dead simple with tools like QuickCheck--it essentially manufactures test cases for you based on invariants that you specify about your code.