`GHC.Conc.Windows` seems to use `[DelayReq]` as a priority queue, and uses `foldr` to insert multiple elements into it. Unless these lists are always very short (are they?) that seems like a bad idea. <details><summary>Trac metadata</summary> | Trac field | Value | | ---------------------- | ---------------- | | Version | 8.4.3 | | Type | Bug | | TypeOfFailure | OtherFailure | | Priority | normal | | Resolution | Unresolved | | Component | Core Libraries | | Test case | | | Differential revisions | | | BlockedBy | | | Related | | | Blocking | | | CC | | | Operating system | Unknown/Multiple | | Architecture | | </details> <!-- {"blocked_by":[],"summary":"GHC.Conc.Windows has a surprising queue","status":"New","operating_system":"Unknown/Multiple","component":"Core Libraries","related":[],"milestone":"8.8.1","resolution":"Unresolved","owner":{"tag":"Unowned"},"version":"8.4.3","keywords":[],"differentials":[],"test_case":"","architecture":"","cc":[""],"type":"Bug","description":"`GHC.Conc.Windows` seems to use `[DelayReq]` as a priority queue, and uses `foldr` to insert multiple elements into it. Unless these lists are always very short (are they?) that seems like a bad idea.","type_of_failure":"OtherFailure","blocking":[]} -->