| $ ghc --make THTest1.hs | Chasing modules from: THTest1.hs | Compiling THTest1TH ( ./THTest1TH.hs, ./THTest1TH.o ) | Compiling THTest1 ( THTest1.hs, THTest1.o ) | | THTest1.hs:10:4: `incrSelf' is not a (visible) method of class `IncrSelf' I've now fixed this bug, in the HEAD. The fix will appear in 6.4.2 (if we release that). Thanks for reporting it. Simon