You mean mtl 2.*, right ? Yes that is a problem. I'm nervous about requiring mtl 2 because when I bumped hledger 0.13's process dependency to 0.14 for similar reasons it made all kinds of trouble for folks who just want to install the hledger core in standard/older haskell environments. On Jan 20, 2011, at 5:11 PM, Dmitry Astapov wrote:
Since hledger-chart depends on Chart, which in turn depends on transformers 0.2.*, it will make a sense to bump all mtl dependencies in hledger to 2.2
When one does "make install" with older GHC (like 6.12.1, for example), and mtl 1.x is available, it would be happily used for hledger-lib and hledger, but compilation of hledger-chart will pull in transformers 0.2 (but not the newer mtl) and will fail due to conflicting instances.