Let me introduce Erlang to you: http://ll2.ai.mit.edu/talks/armstrong.pdf http://ll2.ai.mit.edu/talks/armstrong.pdf Slide 27 describes an Erlang system from th

Let me introduce Erlang to you: http://ll2.ai.mit.edu/talks/armstrong.pdf http://ll2.ai.mit.edu/talks/armstrong.pdf Slide 27 describes an Erlang system from the late 90's/early 2000's that contains 1.7M lines of Erlang, with "99.9999999% reliability" This suggests that complicated compiler type checking is not "the greatest need of high dependability".