I would be interested in helping too, but leaving for a week just this starurday. When i'll come back, and if it's still usefull, i'll be able to write test, especially for - for loops - array indexing - strings maybe ?
And in my dream, i'd like to help coding this, but i'd need time to understand the gpc internals (i know it's gcc front-end and already printed "Writing a compiler Front End", but i had no time until now... ).
What is the time frame ? Do you need the tests before, during or after implementing range checking in the compiler ?
Interested too in these informations :-)