Changes due to ghc api changes in package representation

Also fix a bug with finding the package name and version given a
module. This had become wrong due to the package key changes (it was
very hacky in the first place). We now look up the package key in the
package db to get the package info properly.
Import Data.Word w/o import-list

This is needed to keep the compilation warning free (and thus pass GHC's
./validate) regardless of whether Word is re-exported from Prelude or not

See https://ghc.haskell.org/trac/ghc/ticket/9531 for more details
Follow changes to TypeAnnot in GHC HEAD

Signed-off-by: Austin Seipp <aseipp@pobox.com>
Fix import of 'empty' due to AMP.

Signed-off-by: Austin Seipp <aseipp@pobox.com>
Bump `base` constraint for AMP
Followup changes to addition of -fwarn-context-quantification (GHC Trac #4426)
Properly render package ID (not package key) in index, fixes #329.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Disambiguate string-literals

GHC fails type-inference with `OverloadedStrings` + `Data.Foldable.elem`
otherwise.
Revert "Followup changes to addition of -fwarn-context-quantification"

This reverts commit 4023817d7c0e46db012ba2eea28022626841ca9b temporarily
as the respective feature hasn't landed in GHC HEAD yet, but this commit
blocks later commits from being referenced in GHC HEAD.
Revert "Revert "Followup changes to addition of -fwarn-context-quantification""

This reverts commit db14fd8ab4fab43694139bc203808b814eafb2dc.
It's in HEAD now.
Revert "Fix import of 'empty' due to AMP."

This reverts commit 0cc5bc85e9fca92ab712b68a2ba2c0dd9d3d79f4 since
it turns out we don't need to re-export `empty` from Control.Monad after
all.
Support for PartialTypeSignatures