[Haskell-cafe] Strange message from GHC

[Don Stewart]

Cool message -- forward it to Simon PJ to get more info.

cdsmith:
> I'm running into this in some code I wrote.  What does it mean?  It says 
> to look at -fspec-constr-count, but that flag doesn't seem to be in the 
> GHC documentation.

It's fairly new -- you can get explosions in the number of
specialisations with Specconstr sometimes, and iirc this tunes that
value.
  
> This isn't critical; the code still seems to work fine.  It just makes 
> the build uglier.
> 
> Thanks.  Message below.
> 
> 
> SpecConstr: too many specialisations for one function (see -fspec-constr-
> count):
>     Function: main:Expr.simplifyTerm{v rqC} [lid]
>     Specialisations: [([sc_s2wb{v} [lid], sc_s2wc{v} [lid],
>                         sc_s2wd{v} [lid], sc_s2we{v} [lid], sc_s2wf{v} 
> [lid],
>                         sc_s2wg{v} [lid]],
>                        [main:Expr.Graph{v r51} [gid]
>                           sc_s2wg{v} [lid]
>                           sc_s2wf{v} [lid]
>                           sc_s2we{v} [lid]
>                           sc_s2wd{v} [lid],
>                         base:GHC.Base.:{(w) v 65} [gid]
>                           @ main:Expr.Gen{tc r53}
>                           (main:Expr.Edge{v r4Q} [gid] sc_s2wc{v} [lid])
>                           sc_s2wb{v} [lid]]),
>                       ([sc_s2wh{v} [lid], sc_s2wi{v} [lid], sc_s2wj{v} 
> [lid],
>                         sc_s2wk{v} [lid], sc_s2wl{v} [lid], sc_s2wm{v} 
> [lid]],
>                        [main:Expr.Graph{v r51} [gid]
>                           sc_s2wm{v} [lid]
>                           sc_s2wl{v} [lid]
>                           sc_s2wk{v} [lid]
>                           sc_s2wj{v} [lid],
>                         base:GHC.Base.:{(w) v 65} [gid]
>                           @ main:Expr.Gen{tc r53}
>                           (main:Expr.Ghost{v r4P} [gid] sc_s2wi{v} [lid])
>                           sc_s2wh{v} [lid]]),
>                       ([sc_s2wR{v} [lid], sc_s2wS{v} [lid], sc_s2wT{v} 
> [lid]],
>                        [sc_s2wT{v} [lid],
>                         base:GHC.Base.:{(w) v 65} [gid]
>                           @ main:Expr.Gen{tc r53}
>                           (main:Expr.Vertex{v r4R} [gid] sc_s2wS{v} [lid])
>                           sc_s2wR{v} [lid]]),
>                       ([sc_s2wU{v} [lid], sc_s2wV{v} [lid], sc_s2wW{v} 
> [lid]],
>                        [sc_s2wW{v} [lid],
>                         base:GHC.Base.:{(w) v 65} [gid]
>                           @ main:Expr.Gen{tc r53}
>                           (main:Expr.Vertex{v r4R} [gid]
>                              (base:GHC.Base.I#{(w) v 6d} [gid] sc_s2wV{v} 
> [lid]))
>                           sc_s2wU{v} [lid]])]
> 
> 
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