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 |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |
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