This is along the same lines as #1207 but it uses ErrorInFile, although I renamed to ErrorInModule, as we don't have the file information readily to hand. I also included the error from language-javascript (which is just a String) if the parsing fails. Here's an example output (the error arises from non-ascii characters in string literals, #1265):

$ pulp build --include benchmarks --main Benchmark.Main -O --to main.js
* Building project in /home/harry/documents/code/purescript-sequences
* Build successful.
* Bundling Javascript...
Error in module Benchotron.UI.Console (Regular):

  The module could not be parsed:
  lexical error @ line 67 and column 176

(by the way, that --include option for pulp doesn't exist yet, I'm developing it at the moment)

At the moment, it prints the ModuleType (Regular or Foreign) using the Show instance. Perhaps there's a better way of displaying this information?