[GHC] #13479: Core Lint issues during slowtest

[GHC]

#13479: Core Lint issues during slowtest
-------------------------------------+-------------------------------------
           Reporter:  bgamari        |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  high           |         Milestone:  8.2.1
          Component:  Compiler       |           Version:  8.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  Compile-time
  Unknown/Multiple                   |  crash or panic
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 I'm am seeing Core Lint failurse from the `T5626` test,
 {{{
 *** Core Lint errors : in result of Simplifier ***
 <no location info>: warning:
     [RHS of go_s54c :: [Int] -> (Int, Int, Int, Int)]
     idArity 2 exceeds typeArity 1: go_s54c
 }}}
 The relevant bits of the program are,
 {{{#!hs
 Rec {
 go_s54c [Occ=LoopBreaker] :: [Int] -> (Int, Int, Int, Int)
 [LclId,
  Arity=2,
  CallArity=2,
  Str=<B,U>b,
  Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
          WorkFree=True, Expandable=True, Guidance=NEVER}]
 go_s54c
   = \ (ds_X35o :: [Int]) ->
       case ds_X35o of {
         [] -> case lvl_s4Vm of wild_00 { };
         : y_a34y [Dmd=<B,A>] ys_a34z [Dmd=<B,U>] -> go_s54c ys_a34z
       }
 end Rec }

 lvl_s54d :: (Int, Int, Int, Int)
 [LclId,
  Arity=1,
  Str=x,
  Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
          WorkFree=True, Expandable=True, Guidance=NEVER}]
 lvl_s54d = go_s54c ([] @ Int)
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13479>
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