Bug 2058 – Describe hidden value passed to class member functions

As in C++, D appears to implicitly pass a reference to the class instance into a call to a member function to support references to class member vars and "this". The fact that a hidden var is passed in is documented in reference to nested classes, but not for basic member functions. This behavior is likely well known to experienced c++ developers, but needs to be documented in a language spec. I ran into this trying to pass a class member function into std.algorithm.lowerBound, which of course doesn't work because of the hidden class reference. (There needs to be a way to pass a member function in easily - subject for another bug).

Passing in a member function is easy - they pass as delegate types, rather than function pointer types.

I eventually figured out how to use a delegate here. I had been working too hard at it. At this point, I'm thinking the issue is that lowerBound is specified with "alias less", which doesn't really tell a newbie what is really safe to pass in. Some more detailed docs with basic examples would help, both using standalone functions, and delegates. This is really more a meta issue for stuff in algorithms and other places that can take function references of various forms.

Fixed dmd 1.030 and 2.014