[GHC] #12631: `hpc report` silently ignore non-existent modules

[GHC]

#12631: `hpc report` silently ignore non-existent modules
--------------------------------------+---------------------------
           Reporter:  quabla          |             Owner:
               Type:  bug             |            Status:  new
           Priority:  normal          |         Milestone:
          Component:  Code Coverage   |           Version:  7.10.3
           Keywords:                  |  Operating System:  Linux
       Architecture:  x86_64 (amd64)  |   Type of failure:  Other
          Test Case:                  |        Blocked By:
           Blocking:                  |   Related Tickets:
Differential Rev(s):                  |         Wiki Page:
--------------------------------------+---------------------------
 {{{
 hpc report my.tix NotExistingModule
 }}}

 reports a coverage of 100% (0/0)

 This was confusing to me since I didn't even wanted to supply a module but
 rather two arguments to --hpcdir without noting that the flag has to be
 given multiple times. Instead of a ***Module ''hpc/path'' not found***
 message, I got 100% converage.

 {{{
 $ hpc version
 hpc tools, version 0.67
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12631>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler