[GHC] #15130: Hadrian doesn't rebuild changed `CoreUtils.hs`

[GHC]

#15130: Hadrian doesn't rebuild changed `CoreUtils.hs`
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           Reporter:  tdammers        |             Owner:  (none)
               Type:  bug             |            Status:  new
           Priority:  normal          |         Milestone:  8.6.1
          Component:  Build System    |           Version:  8.4.2
           Keywords:                  |  Operating System:  Linux
       Architecture:  x86_64 (amd64)  |   Type of failure:  Other
          Test Case:                  |        Blocked By:
           Blocking:                  |   Related Tickets:
Differential Rev(s):                  |         Wiki Page:
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 When compiling stage2 with Hadrian, freezing stage1 causes changes to
 `CoreUtils.hs` to be ignored, and `CoreUtils.hs` not being recompiled.

 The following steps should reproduce the problem:

 1. Make a debug build with Hadrian: `./hadrian/build.sh --flavour=Devel2`
 2. Rebuild with freeze1: `./hadrian/build.sh --flavour=Devel2 --freeze1`
 3. Edit `compiler/coreSyn/CoreUtils.hs`, adding some change that is easily
 detected in the output
 4. Rebuild with freeze1: `./hadrian/build.sh --flavour=Devel2 --freeze1`
 5. Observe how `CoreUtils` does not appear in the list of modules Hadrian
 is compiling, and how changes to that file do not end up in the stage2
 compiler.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15130>
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