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Summary

powModNatural returns a wrong answer.

Steps to reproduce

import Data.Bits
import GHC.Natural

main = print $ powModNatural 0 (fromIntegral n) 2
  where
    n = 1 `shiftL` 64 :: Integer
    {-# NOINLINE n #-}

$ ghc -O1 powmod.hs && ./powmod
[1 of 1] Compiling Main             ( powmod.hs, powmod.o )
Linking powmod ...
1

Expected behavior

Expected answer is 0. Removing NOINLINE, changing fromIntegral to fromInteger, or switching to -O0 all rectify the situation.

Environment

• GHC version used: 9.0.1

Optional:

• Operating System: MacOS
• System Architecture: x64