[Haskell-cafe] Timing out a pure evaluation of an expression I did not write myself

Bertram Felgenhauer bertram.felgenhauer at googlemail.com
Wed Dec 19 11:31:46 UTC 2018

Ryan Reich wrote:
> I expected something like that. I'm all the way back in ghc-8.2.2, but I
> think what this really shows is that the flag is unreliable and
> version-dependent.

The program terminates for me with ghc 8.0.2, 8.2.2, 8.4.3, and 8.6.1,
if compiled with -O -fno-omit-yields; of the versions that I have around
only version 7.8.4 supports -fno-omit-yields but produces a
non-terminating program. This is on x86-64.

I suspect that the real problem is that ghc's recompilation check does
not take -fno-omit-yields into account before version 8.4.1, so you have
to force a clean build for the flag to take effect.



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