Error: yesod-fay depends on type-eq which failed to install.

[cies]

I've encountered this error before. I merely report it here so it is documented for other who run into it. Today when using LTS Haskell and a completely fresh install of GHC-7.8.4 and cabal-1.20 (as by the install instructions for Ubuntu on haskell.org), I got:

yesod-fay-0.7.1 depends on type-eq-0.4.2 which failed to install.

When running cabal install -j --enable-tests --max-backjumps=-1 --reorder-goals on a newly init'ed Yesod "Postgres+Fay" (pf) project.

The workaround is: run the cabal install command again.