I try download and build 6.6.1 ( as ubntu has just 6.6 on package) and most went ok ( compiler and most libs) but arrows i tried and download arrow 0.2 from hackage but no more success any ideas ? ( knowing 6.6 is also on the machine if that matters) luc@haserv:~/src/arrows-0.2$ runghc Setup.hs build Preprocessing library arrows-0.2... Building arrows-0.2... [ 1 of 13] Compiling Data.Stream ( Data/Stream.hs, dist/build/Data/Stream.o ) [ 2 of 13] Compiling Control.Arrow.Transformer ( Control/Arrow/Transformer.hs, dist/build/Control/Arrow/Transformer.o ) [ 3 of 13] Compiling Control.Arrow.Operations ( Control/Arrow/Operations.hs, dist/build/Control/Arrow/Operations.o ) [ 4 of 13] Compiling Control.Arrow.Transformer.CoState ( Control/Arrow/Transformer/CoState.hs, dist/build/Control/Arrow/Transformer/CoState.o ) [ 5 of 13] Compiling Control.Arrow.Internals ( Control/Arrow/Internals.hs, dist/build/Control/Arrow/Internals.o ) [ 6 of 13] Compiling Control.Arrow.Transformer.Automaton ( Control/Arrow/Transformer/Automaton.hs, dist/build/Control/Arrow/Transformer/Automaton.o ) Control/Arrow/Transformer/Automaton.hs:98:0: Illegal instance declaration for `ArrowWriter w (Automaton a)' (the Coverage Condition fails for one of the functional dependencies; Use -fallow-undecidable-instances to permit this) In the instance declaration for `ArrowWriter w (Automaton a)' Control/Arrow/Transformer/Automaton.hs:104:0: Illegal instance declaration for `ArrowError r (Automaton a)' (the Coverage Condition fails for one of the functional dependencies; Use -fallow-undecidable-instances to permit this) In the instance declaration for `ArrowError r (Automaton a)' Control/Arrow/Transformer/Automaton.hs:115:0: Illegal instance declaration for `ArrowReader r (Automaton a)' (the Coverage Condition fails for one of the functional dependencies; Use -fallow-undecidable-instances to permit this) In the instance declaration for `ArrowReader r (Automaton a)' Control/Arrow/Transformer/Automaton.hs:120:0: Illegal instance declaration for `ArrowState s (Automaton a)' (the Coverage Condition fails for one of the functional dependencies; Use -fallow-undecidable-instances to permit this) In the instance declaration for `ArrowState s (Automaton a)' Control/Arrow/Transformer/Automaton.hs:126:0: Illegal instance declaration for `ArrowAddWriter w (Automaton a) (Automaton a')' (the Coverage Condition fails for one of the functional dependencies; Use -fallow-undecidable-instances to permit this) In the instance declaration for `ArrowAddWriter w (Automaton a) (Automaton a')' I discovered recently that my ubuntu package were providing only 6.6 and the latest cabal needs 6.6.1. when rebuilding this one from the tar ( not the head on darcs) most went ok but the arrows lib. I also tried to get it from hackage, but idem: ( I also have 6.6 on the machaine dos it matters ?) here is the build from hacakge with runghc : luc@haserv:~/src/arrows-0.2$ runghc Setup.hs build Preprocessing library arrows-0.2... Building arrows-0.2... [ 1 of 13] Compiling Data.Stream ( Data/Stream.hs, dist/build/Data/Stream.o ) [ 2 of 13] Compiling Control.Arrow.Transformer ( Control/Arrow/Transformer.hs, dist/build/Control/Arrow/Transformer.o ) [ 3 of 13] Compiling Control.Arrow.Operations ( Control/Arrow/Operations.hs, dist/build/Control/Arrow/Operations.o ) [ 4 of 13] Compiling Control.Arrow.Transformer.CoState ( Control/Arrow/Transformer/CoState.hs, dist/build/Control/Arrow/Transformer/CoState.o ) [ 5 of 13] Compiling Control.Arrow.Internals ( Control/Arrow/Internals.hs, dist/build/Control/Arrow/Internals.o ) [ 6 of 13] Compiling Control.Arrow.Transformer.Automaton ( Control/Arrow/Transformer/Automaton.hs, dist/build/Control/Arrow/Transformer/Automaton.o ) Control/Arrow/Transformer/Automaton.hs:98:0: Illegal instance declaration for `ArrowWriter w (Automaton a)' (the Coverage Condition fails for one of the functional dependencies; Use -fallow-undecidable-instances to permit this) In the instance declaration for `ArrowWriter w (Automaton a)' Control/Arrow/Transformer/Automaton.hs:104:0: Illegal instance declaration for `ArrowError r (Automaton a)' (the Coverage Condition fails for one of the functional dependencies; Use -fallow-undecidable-instances to permit this) In the instance declaration for `ArrowError r (Automaton a)' Control/Arrow/Transformer/Automaton.hs:115:0: Illegal instance declaration for `ArrowReader r (Automaton a)' (the Coverage Condition fails for one of the functional dependencies; Use -fallow-undecidable-instances to permit this) In the instance declaration for `ArrowReader r (Automaton a)' Control/Arrow/Transformer/Automaton.hs:120:0: Illegal instance declaration for `ArrowState s (Automaton a)' (the Coverage Condition fails for one of the functional dependencies; Use -fallow-undecidable-instances to permit this) In the instance declaration for `ArrowState s (Automaton a)' Control/Arrow/Transformer/Automaton.hs:126:0: Illegal instance declaration for `ArrowAddWriter w (Automaton a) (Automaton a')' (the Coverage Condition fails for one of the functional dependencies; Use -fallow-undecidable-instances to permit this) In the instance declaration for `ArrowAddWriter w (Automaton a) (Automaton a')' Control/Arrow/Transformer/Automaton.hs:135:0: Illegal instance declaration for `ArrowAddReader r (Automaton a) (Automaton a')' (the Coverage Condition fails for one of the functional dependencies; Use -fallow-undecidable-instances to permit this) In the instance declaration for `ArrowAddReader r (Automaton a) (Automaton a')' Control/Arrow/Transformer/Automaton.hs:144:0: Illegal instance declaration for `ArrowAddState r (Automaton a) (Automaton a')' (the Coverage Condition fails for one of the functional dependencies; Use -fallow-undecidable-instances to permit this) In the instance declaration for `ArrowAddState r (Automaton a) (Automaton a')' luc@haserv:~/src/arrows-0.2$ ------------------------------------------------------- here is a make from the build in the libraries tree under ghc 6.6.1 luc@haserv:~/Desktop/ghc-6.6.1-src/ghc-6.6.1/libraries/arrows$ make gcc -E -undef -traditional -P \ -DIMPORT_DIR='"/home/luc/Desktop/ghc-6.6.1-src/ghc-6.6.1/libraries/arrows"' \ -DLIB_DIR='"/home/luc/Desktop/ghc-6.6.1-src/ghc-6.6.1/libraries/arrows"' \ -DINCLUDE_DIR='"/home/luc/Desktop/ghc-6.6.1-src/ghc-6.6.1/libraries/arrows/include"' \ -DDATA_DIR='"/home/luc/Desktop/ghc-6.6.1-src/ghc-6.6.1/libraries/arrows"' \ -DHTML_DIR='"/home/luc/Desktop/ghc-6.6.1-src/ghc-6.6.1/libraries/arrows/html"' \ -DHADDOCK_IFACE='"/home/luc/Desktop/ghc-6.6.1-src/ghc-6.6.1/libraries/arrows/html/arrows.haddock"' \ -DFPTOOLS_TOP_ABS='"/home/luc/Desktop/ghc-6.6.1-src/ghc-6.6.1"' \ -x c -I../../includes -Iinclude -DPACKAGE=arrows -DVERSION=0.2.1 -DPKG_LIBDIR='"/usr/local/lib/ghc-6.6.1"' -DPKG_DATADIR='"/usr/local/share/ghc-6.6.1"' package.conf.in | \ grep -v '^#pragma GCC' | \ sed -e 's/""//g' -e 's/:[ ]*,/: /g' >package.conf.inplace gcc -E -undef -traditional -P -DINSTALLING \ -DIMPORT_DIR='"/usr/local/lib/ghc-6.6.1/imports"' \ -DLIB_DIR='"/usr/local/lib/ghc-6.6.1"' \ -DINCLUDE_DIR='"/usr/local/lib/ghc-6.6.1/include"' \ -DDATA_DIR='"/usr/local/share/ghc-6.6.1"' \ -DHTML_DIR='"/usr/local/share/ghc-6.6.1/html/libraries/arrows"' \ -DHADDOCK_IFACE='"/usr/local/share/ghc-6.6.1/html/libraries/arrows/arrows.haddock"' \ -x c -I../../includes -Iinclude -DPACKAGE=arrows -DVERSION=0.2.1 -DPKG_LIBDIR='"/usr/local/lib/ghc-6.6.1"' -DPKG_DATADIR='"/usr/local/share/ghc-6.6.1"' package.conf.in | \ grep -v '^#pragma GCC' | \ sed -e 's/""//g' -e 's/:[ ]*,/: /g' >package.conf.installed ../../utils/ghc-pkg/ghc-pkg-inplace update - --force-files > make: *** [Control/Arrow/Internals.o] Error 1 luc@haserv:~/Desktop/ghc-6.6.1-src/ghc-6.6.1/libraries/arrows$