Pattern match checker exceeded (2000000) iterations

graphviz seems a nice benchmark (not too large, few dependencies) that highlights compiler performance problems on "trivial" source code (cf. https://hackage.haskell.org/package/graphviz-2999.18.0.2/docs/src/Data-GraphViz-Attributes-Complete.html#sameAttribute)

Compilation of Compiling Data.GraphViz.Attributes.Colors.X11 and Data.GraphViz.Attributes.Values takes >= 1 second each, and the following happens:

cabal install graphviz-2999.18.0.2 --allow-newer

...

[17 of 31] Compiling Data.GraphViz.Attributes.Complete ( Data/GraphViz/Attributes/Complete.hs, dist/dist-sandbox-e6f2c124/build/Data/GraphViz/Attributes/Complete.o )

Data/GraphViz/Attributes/Complete.hs:1013:1: warning:
    Pattern match checker exceeded (2000000) iterations in
    an equation for ‘sameAttribute’. (Use -fmax-pmcheck-iterations=n
    to set the maximun number of iterations to n)

I do welcome that ghc emits this warning - I expect you want its occurence to be reported as a bug?

Trac metadata

Trac field	Value
Version	8.0.1-rc3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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