What is Tdummy doing in (may|does)PointTo?

[Andrei Alexandrescu via Digitalmars-d]

https://dlang.org/library/std/exception/may_point_to.html
https://dlang.org/library/std/exception/does_point_to.html

We have an unfortunate pattern in Phobos: things that start out as 
simple ideas with nice implementations (in this case pointsTo) slowly 
change into complicated artifacts with undocumented rationale. We really 
should rein in documentation, not only external but also internal. In 
this case I cannot for the life of me figure what Tdummy does, and the 
only appearance of the name is in the respective definitions.

Not to mention it uses incorrect spacing ("Tdummy=void", should be 
"Tdummy = void") :o).


Andrei