Cabal install

[Simon Peyton Jones]

Dear friendly Cabal folk
Here's what happened to me today

bash$ cabal install lhs2tex

cabal: Could not resolve dependencies:

[__0] next goal: report (user goal)

[__0] rejecting: report-0.1.0.0 (conflict: requires UnsaturatedTypeFamilies)

[__0] fail (backjumping, conflict set: report)

After searching the rest of the dependency tree exhaustively, these were the

goals I've had most trouble fulfilling: report
Crumbs.  What is 'report'?  Why does it need UnsaturatedTypeFamilies?   I'm totally lost.
Then, in an inspired moment, I thought to change to a different directory, ~/tmp.
Then quite different things happened - it downloaded and built relevant libraries.
I think that there just happened to be a .cabal file in the original directory I was in at the time.  That appears to affect what 'cabal install' does in a truly radical way.
My point is this: this is terribly confusing for the user (at least for this on).   I'd be shocked if 'apt install blah' behaved utterly differently in different directories.  I'm going to make a little empty directory somewhere, and cd to it before invoking cabal in future.  But that just feels like a workaround, not a solution.
I'm not saying it's wrong - just giving you a data point that it had one user completely stumped
Simon



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