#7548: GHC API dependency analysis is broken
Reporter:  MikolajKonarski  |          Owner:                
    Type:  bug              |         Status:  new           
Priority:  normal           |      Component:  GHC API       
 Version:  7.4.2            |       Keywords:                
      Os:  Linux            |   Architecture:  x86_64 (amd64)
 Failure:  None/Unknown     |      Blockedby:                
Blocking:                   |        Related:                
 Sometimes, when a module fails to compile, GHC API invalidates other
 modules that do not depend on it (the attached example shows that) and
 sometimes the opposite --- it does not invalidate modules it should (I
 haven't created a standalone example with that so far). The problem is
 deterministic, but depends on the order in which targets are added using

 Generally, it seems if module B imports A, it correctly assumes A does not
 depend on B, but if B does not import A, it sometimes assumes A must
 depend on B, even if neither mentions the other. See comments in the

 To reproduce, compile the example with

 ghc --make typecheck-dir.hs -package ghc-7.4.2

 create directory ./tmp and run typecheck-dir. You should see that module
 XXX is needlessly recompiled.

Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7548>
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