In addition, with the PDC near the corner, informations are beginning to filtrate about C#4. As can be seen on several videos on Channel 9 (this one particularly), the C#4 design team is seriously planning to add language features that will help programmers do multi-threaded and concurrent programs.

Most noticeably, Anders speaks, around 5:30, about compiler-enforced purity (which can be already found in other imperative language like D) and automatic isolation of objects (I suspect it's a sort of STM where object manipulations are bundled in separate transaction).

Both of them also make very good points about the difficulty for compilers to assert that a piece of code is parallelizable. Since even experienced programmers can make mistakes about the thread-safety of their code, it appears hard for compiler to automagically assure that a piece of code is indeed side effect free in a imperative world like C# (a problem that language like Haskell don’t know, being pure by default). I also like the position of Anders about C# as an hybrid imperative/functional language.

/me is looking forward to PDC for more parallel goodness and to start implementing these features in Mono .