a) Martin Odersky has admitted as much[1]. b) The compiler internals are reportedly a mess[2]--likely due at least in part to the extreme number of different s

a) Martin Odersky has admitted as much[1]. b) The compiler internals are reportedly a mess[2]--likely due at least in part to the extreme number of different syntax variants. c) I find rule 4.1 in OP interesting ("SHOULD avoid concurrency like the plague it is"). According to Odersky's Coursera course[3], one of the main advantages of functional programming as enabled by Scala is easy, safer concurrency (reduced/absent mutable shared state). Yet here we see a presumably seasoned Scala veteran basically saying that this is a failure and we should avoid concurrency whenever possible because it results in too many bugs. 1. http://www.infoworld.com/article/2609013/java/scala-founder--language-due-for--fundamental-rethink-.html http://www.infoworld.com/article/2609013/java/scala-founder-... 2. https://www.youtube.com/watch?v=TS1lpKBMkgg https://www.youtube.com/watch?v=TS1lpKBMkgg 3. https://www.coursera.org/course/progfun https://www.coursera.org/course/progfun