Resolving dependencies...
Downloading alex-2.3...
[1 of 1] Compiling Main             ( /tmp/alex-2.3-1199/alex-2.3/Setup.lhs, /tmp/alex-2.3-1199/alex-2.3/dist/setup/Main.o )

/tmp/alex-2.3-1199/alex-2.3/Setup.lhs:12:26:
    Module `System.IO.Error' does not export `try'
Failed to install alex-2.3
cabal: Error: some packages failed to install:
alex-2.3 failed during the configure step. The exception was:
ExitFailure 1