Usability of "allMembers and derivedMembers traits now only return visible symbols"

[Ali Çehreli via Digitalmars-d]

On 09/04/2016 05:37 AM, David Nadlinger wrote:
 > On Sunday, 4 September 2016 at 12:33:07 UTC, Andrei Alexandrescu wrote:
 >> Thanks for answering. Yes, we really need introspection of private
 >> members. One way or another we need to support that.
 >
 > Do we, though? It's easy to state a general claim like this, but I find
 > it hard to actually justify.
 >
 >  — David

Let me flip the question: What harm can there be when I pass my type to 
a template and that template accesses the private members?

Ali