[GHC] #14170: 8.2.1 regression: GHC fails to simplify `natVal`

[GHC]

#14170: 8.2.1 regression: GHC fails to simplify `natVal`
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        Reporter:  vagarenko         |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.2.3
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Bodigrim):

 I am interested in this issue due to #14465. I tried to prepare a patch
 Phab:D4212, but stumbled upon a build issue. Can someone please explain
 what went wrong? Sorry, I am new to GHC build system.

 {{{
 "inplace/bin/ghc-stage1" -hisuf hi -osuf  o -hcsuf hc -static  -O0 -H64m
 -Wall      -this-unit-id base-4.11.0.0 -hide-all-packages -i
 -ilibraries/base/. -ilibraries/base/dist-install/build -Ilibraries/base
 /dist-install/build -ilibraries/base/dist-install/build/./autogen
 -Ilibraries/base/dist-install/build/./autogen -Ilibraries/base/include
 -optP-DOPTIMISE_INTEGER_GCD_LCM -optP-include -optPlibraries/base/dist-
 install/build/./autogen/cabal_macros.h -package-id rts -package-id ghc-
 prim-0.5.2.0 -package-id integer-gmp-1.0.1.0 -this-unit-id base
 -XHaskell2010 -O  -no-user-package-db -rtsopts  -Wno-trustworthy-safe
 -Wno-deprecated-flags     -Wnoncanonical-monad-instances  -odir
 libraries/base/dist-install/build -hidir libraries/base/dist-install/build
 -stubdir libraries/base/dist-install/build   -dynamic-too -c
 libraries/base/./GHC/Natural.hs -o libraries/base/dist-
 install/build/GHC/Natural.o -dyno libraries/base/dist-
 install/build/GHC/Natural.dyn_o

 <interactive>:1:1: error:
     Bad interface file: libraries/base/dist-install/build/GHC/Natural.hi
         libraries/base/dist-install/build/GHC/Natural.hi: openBinaryFile:
 does not exist (No such file or directory)
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14170#comment:6>
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