Isn't `each` too much of a good thing?

[Andrei Alexandrescu]

On 9/17/20 12:18 PM, Andrei Alexandrescu wrote:
[snip]

Can't believe I forgot to mention what would be the ultimate smoking 
gun: all of that crap spills into the user-visible documentation: each 
is constrained on symbols not documented and not available to the user!

https://dlang.org/library/std/algorithm/iteration/each.each.html

Sure, one may have a vague idea what isForeachIterable or 
isRangeIterable are, but these are neither documented, nor accessible to 
user code. The user's only chance is peruse the source code or "build 
and pray".

We really must draw the line at defining constraints in terms of private 
symbols. That's a no-no.