The special procedure syntax has been a constant source of trouble and confusion for people learning Scala, while providing no benefit except a few saved characters over using the standard method syntax.
To not cause pointless work for people, this migration has to happen in multiple steps:
- Update the style guide and the specification
- Update tools (IDEs, Scalariform, ...)
- Deprecate procedure syntax
Mailing list discussion: https://groups.google.com/d/topic/scala-internals/q1YX7NC1geM/discussion
ScalaDays 2013 Keynote: http://www.parleys.com/play/51c1994ae4b0d38b54f4621b/chapter47