Surprised by hashes of arrays of arrays

[Jens Mueller]

thedeemon wrote:
> On Thursday, 27 February 2014 at 10:12:46 UTC, Jens Mueller wrote:
> >As you may conclude from this post I find this behavior odd. I
> >expect a
> >hash implementation to follow indirections by calling the  hashing
> >functions recursively.
> 
> How shall it work with cycles in object graphs?

That's probably the rational behind the implementation.
Probably also the reason why Tuple and VariantN implement no toHash,
i.e., it is impossible to provide an efficient implementation for toHash
for some generic types. But the consequences are rather dramatic because
whenever I need hashing for a type (with indirections but no cycles are
created at runtime) I must implement my own types because generic ones
cannot provide it. It may be useful to provide a generic hash function
for these cases in Phobos.

Jens