Why Does Dscanner Warn About a Missing toHash if opEquals is Defined?

[qlksgj via Digitalmars-d-learn]

On Monday, 1 August 2016 at 10:35:29 UTC, pineapple wrote:
> Every hashing function will produce collisions.

Not totally true: when the hash map content is static (i.e known 
at compile time) there are probabilities that a perfect hashing 
function exists. But these kind of functions are a bit special 
because each byte of the value maps to another byte. See the gnu 
tool "gperf" for example.