Arithmetic overflow from (minBound :: Int) `quot` (-1)
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.
Trac metadata
| 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 |