This is an auto-filled bug because dev-haskell/semigroupoids fails to compile. The issue was originally discovered on amd64, but it may be reproducible on other arches as well. If you think that a different summary clarifies the issue better, feel free to change it. Attached build log and emerge --info. NOTE: If you need further logs, feel free to ask..
Created attachment 638540 [details] build.log build log and emerge --info
Latest package version is semigroupoids-5.3.4 . Unable to reproduce with this version. The version mentioned in this bug has already been removed from the tree. Closing.