Time [in minutes]: <= 20 minutes

Platform [OS, libraries, etc.]:
OS X 10.9
GHC 7.6.3 / Haskell 2013.2.0.0

Skill level:
- I can build complex software like GCC and the Linux kernel

Detailed evaluation:

The package doesn't build as-is, but the needed changes are minimal in size (see
fixes.patch) and easy to do *for a competent Haskell programmer* (less than half
an hour). As pointed out by the original reviewer, the code probably would have worked on
older GHCs (older than 7.2.1, judging from
https://ghc.haskell.org/trac/ghc/ticket/4958#comment:1).

After the patch, I built the program with:
  cabal build
and tested it with:
  ./dist/build/interpreter/interpreter testsuite/test20.hr
(suggested in the README) which seems to terminate successfully.

Running it on all examples confirms the presence of a few unsuccessful results, possibly the bugs acknowledged in the README. But I didn't investigate much into it:

for i in testsuite/*.hr; do echo $i; ./dist/build/interpreter/interpreter $i > /dev/null; done

==
Anecdotically, last time I tried running this code (I had looked at the paper
before) I did give up before they did (because of lack of time). So they can't
be blamed.

General lesson: please write down which GHC version you tested with.

Diffstat for patch for GHC 7.6.3:
$ diffstat -p1 implicit.patch
 Main.hs         |    2 +-
 Syntax.hs       |    2 +-
 SyntaxSource.hs |    2 +-
 rho_poly.cabal  |    1 -
 4 files changed, 3 insertions(+), 4 deletions(-)