I built ghc-6.10.1.20090314 on OS X 10.5.6 (Intel) using ghc 6.8.2 as a bootstrap compiler. The build was done using the MacPorts infrastructure. Summary test results: OVERALL SUMMARY for test run started at Tue Mar 17 15:31:38 EDT 2009 2334 total tests, which gave rise to 12487 test cases, of which 0 caused framework failures 2460 were skipped 9709 expected passes 258 expected failures 0 unexpected passes 60 unexpected failures Unexpected failures: 2469(ghci) apirecomp001(normal) bits (normal ,optc,hpc,optasm,profc,profasm,ghci,threaded1,threaded2,profthreaded) conc049(hpc) conc068(normal) derefnull(profc,profthreaded) divbyzero(profc,profthreaded) genUpTo (normal ,optc,hpc,optasm,profc,profasm,ghci,threaded1,threaded2,profthreaded) length001(optc,hpc,optasm,profc,profasm,threaded2,profthreaded) num009 (normal ,optc,hpc,optasm,profc,profasm,ghci,threaded1,threaded2,profthreaded) num012 (normal ,optc,hpc,optasm,profc,profasm,ghci,threaded1,threaded2,profthreaded) signals002(ghci) signals004(ghci,threaded1,threaded2,profthreaded) I haven't looked at the errors in detail, but generally the release candidate seems OK. BTW, a test target will be added to MacPorts's portfile for the 6.10.2 release, which will let you run the test suite by typing > sudo port test ghc and if you then install the tested build, a record of the test will be saved in $PREFIX/share/ghc-<version>/. Best Wishes, Greg