According to the documentation for Data.Int, “All arithmetic is performed modulo 2!\^n, where n is the number of bits in the type.” However, this promise is broken by the following exception: ``` Prelude> (minBound :: Int) `quot` (-1) *** Exception: arithmetic overflow ``` (This also occurs with Int8, Int16, Int32, and Int64, and likewise for `div`.) If all arithmetic is performed modulo 2!\^n, I would rather expect the above to evaluate to `minBound`, since after all `minBound * (-1) == minBound`. The fact that an exception is raised adds an unnecessary burden in pure code to ensure `quot` (or `div`) is never called with these specific arguments. <details><summary>Trac metadata</summary> | Trac field | Value | | ---------------------- | ------------------------ | | Version | 7.6.3 | | Type | Bug | | TypeOfFailure | IncorrectResultAtRuntime | | Priority | normal | | Resolution | Unresolved | | Component | libraries/haskell2010 | | Test case | | | Differential revisions | | | BlockedBy | | | Related | | | Blocking | | | CC | | | Operating system | | | Architecture | | </details> <!-- {"blocked_by":[],"summary":"Arithmetic overflow from (minBound :: Int) `quot` (-1)","status":"New","operating_system":"","component":"libraries/haskell2010","related":[],"milestone":"","resolution":"Unresolved","owner":{"tag":"Unowned"},"version":"7.6.3","keywords":[],"differentials":[],"test_case":"","architecture":"","cc":[""],"type":"Bug","description":"According to the documentation for Data.Int, “All arithmetic is performed modulo 2!^n, where n is the number of bits in the type.”\r\n\r\nHowever, this promise is broken by the following exception:\r\n\r\n{{{\r\nPrelude> (minBound :: Int) `quot` (-1)\r\n*** Exception: arithmetic overflow\r\n}}}\r\n\r\n(This also occurs with Int8, Int16, Int32, and Int64, and likewise for `div`.)\r\n\r\nIf all arithmetic is performed modulo 2!^n, I would rather expect the above to evaluate to `minBound`, since after all `minBound * (-1) == minBound`. The fact that an exception is raised adds an unnecessary burden in pure code to ensure `quot` (or `div`) is never called with these specific arguments.","type_of_failure":"IncorrectResultAtRuntime","blocking":[]} -->