I run haskell on Mac OS X (Snow Leopard). After upgrading my Xcode installation to 4.0 I had a tricky time getting ghc working again; the version bundled with the Haskell Platform no longer works and I had to compile a recent snapshot (ghc-7.1.20110315) from source. This worked fine, but now when I compile my code I keep getting really weird warnings. For instance: ld: warning: could not create compact unwind for .LFB3: non-standard register 5 being saved in prolog and SpecConstr Function `$w$j{v s3hL} [lid]' has one call pattern, but the limit is 0 Use -fspec-constr-count=n to set the bound Use -dppr-debug to see specialisations SpecConstr Function `$w$j{v s3ic} [lid]' has two call patterns, but the limit is 1 Use -fspec-constr-count=n to set the bound Use -dppr-debug to see specialisations The code seems to work, but this is quite irritating. Is there anything that can be done about these warnings? Thanks, Mike