Kinds of containers

[Andrei Alexandrescu via Digitalmars-d]

On 10/24/15 3:19 PM, Timon Gehr wrote:
> Even if this was possible, it would not be a very good idea. Persistent
> data structures have use cases that would be hindered by required
> transitive immutability.

This part I don't quite get. Are there any languages that offer 
containers with immutable topology but mutable slots, and call them 
persistent data structures? -- Andrei