Is there any chance to introduce concepts/traits/typeClasses in dlang?

[rikki cattermole]

I have already gone down this path.

My design for named arguments was step one, but sadly DIP 1020 is dead.

My preference is towards signatures from ML.

Pretty simple concept, but in practice it is just as complex as classes 
are and would be just as big.

I don't think Walter has made a decision about this, but for reference: 
if a language had a similar scope to D and it supported them, I would 
probably jump. They would be a major improvement over D today for 
documenting API's especially with meta-programming considered.