[maxlybbert]

I hadn't followed the original proposal closely, so I can't give a complete list. One feature I know about, that was implementable but very expensive, was the ability to specify multiple ways that a type could match a concept. For instance, a Sortable concept could mean the type has an operator<, or could be passed to the function compare(). I'm sure there was a way to handle cases where a type had both. But then, if you had a type with a method, say lessThan(), you could somehow specify that was an acceptable operator<, and then use anything that relied on the Sortable concept. As far as I know, that isn't in "concepts light."