It has been pointed out before that in order for Safe Haskell to be useful, libraries (especially core libraries) should be annotated properly with Safe Haskell LANGUAGE pragmas. However, that would make these libraries unusable with alternative Haskell implementations, even if otherwise they these libraries are Haskell2010. To quote the standard: If a Haskell implementation does not recognize or support a particular language feature that a source file requests (or cannot support the combination of language features requested), any attempt to compile or otherwise use that file with that Haskell implementation must fail with an error. Should it be advised to surround safe annotations with CPP #ifs? Or does anyone see a better way out of this contradiction? Roman