This is to add to my last letter. It is curious that this 7.02 candidate stucks at оverlapping instances only when compiling the test: T_cubeext.hs:143:9: Overlapping instances for LinSolvRing (UPol k) arising from a use of `ct' ... In earlier versions, if any of them stuck at оverlapping instances, the report was earlier, when compiling the DoCon library. ----------- Mechveliani