-Xelide-level and -Xelide-methods-below=1000 not recognized by compiler

Hi,

I am using the scala 2.8 nightly build: 2.8.0.r21183-b20100316020204. I wanted to try out the elidable annotation but the compiler flags are not being recognized by the compiler. Is this broken functionality, functionality that has change but is not documented or functionality that will be available in the future?

Jesse