Add note about enumBounded

[thumphries]

'enumBounded' is partial in some cases. Usually you actually want something like Gen.linear minBound maxBound or similar. The error message is pretty inscrutable when you mess it up (no source locations), so I think a cautionary message is worthwhile.

Bikeshed on wording welcome

[jacobstanley]

Maybe we can do a check and give an error which is more sensible?

[moodmosaic]

I think we need both―a note in the comments, so it shows up in the docs, and also a check with an error message (in the error message we can put that same stuff as in the notes).

[moodmosaic]

Should be OK to merge this as-is and have the check on a different PR, if that's easier.

[moodmosaic]

Bikeshed on wording welcome

Hmm, perhaps we should mention what the docs say for fromEnum as well?

Convert to an Int. It is implementation-dependent what fromEnum returns when applied to a value that is too large to fit in an Int.

[jacobstanley]

I'm not sure the fromEnum docs add that much? it kind of implies that it might actually work when it probably won't, it is "more correct" but I think just exploding is probably what is going to happen.

[moodmosaic]

Because it's fromEnum that isn't total at the end:

diff --git a/hedgehog/test/Test/Hedgehog/Text.hs b/hedgehog/test/Test/Hedgehog/Text.hs
index 0a11e91..a320100 100644
--- a/hedgehog/test/Test/Hedgehog/Text.hs
+++ b/hedgehog/test/Test/Hedgehog/Text.hs
@@ -29,7 +29,7 @@ genOdd =

 genSeed :: Gen Seed
 genSeed =
-  Seed <$> Gen.word64 Range.constantBounded <*> fmap fromIntegral genOdd
+  Seed <$> Gen.enumBounded <*> fmap fromIntegral genOdd

 genPrecedence :: Gen Int
 genPrecedence =

[thread killed]
test.exe:
  Enum.fromEnum{Word64}:
    value (18446744073709551615) is outside of Int's bounds
      (-9223372036854775808,9223372036854775807)

But yeah you're probably right that we might not need to get into such detail.

[thumphries]

Will mess around and try to produce a better error.

Happy to kill the documentation if y'all prefer. I hadn't quite joined the dots that this had to be going via fromEnum, so I definitely overuse this function where I probably shouldn't.

[moodmosaic]

Yeah, I think adding a check in order to provide a reasonable error is better. But the notes you've added I think will show up nicely in the docs 😃

vs

It's up to you, though. 🎸

[jacobstanley]

I think the error would be good, but no reason to hold up this comment.