[Haskell-cafe] instance Enum Double considered not entirely great?

[Evan Laforge]

> I actually think the brokenness of Ord for floating point values is
> worse in many ways, as demonstrated by the ability to insert a value
> into a Data.Set.Set and have other values "disappear" from the set as
> a result. Getting an unexpected element in a list doesn't really seem
> as bad as silently corrupting entire data structures.

Whoah, that's scary.  What are some examples of this happening?  Does
this mean it's unsafe to store Doubles in a Map?