Motions 2019 11 lwg 16: P1870R1 forwarding-range<T> is too subtle

[burblebee]

Fixes #3418.

Issues with paper:

• [range.access.begin]/p1 adds "Given a subexpression E and an lvalue t that denotes the same object as E", but E is a subexpression, not an object.
  Same for [range.access.end]/p1, [range.access.rbegin]/p1, and [range.access.rend]/p1.
• [range.range] range-impl is removed but is still referenced in p2 and p3.

Other editorial issues:

• cv-unqualified or \cv-unqualified?
  The spec is inconsistent in its representation of cv-unqualified v. /cv/-unqualified.
• When to use \deflibconcept?
  Some concept definitions in the library use \deflibconcept, others don't.
  Also fix inconsistencies in the of \defexposconcept for \expos concepts.
• The library is inconsistent in its use of \exposconcept v. \tcode{\placeholder

Fixes cplusplus/papers#620
Fixes cplusplus/nbballot#275
Fixes cplusplus/nbballot#276
Fixes cplusplus/nbballot#272

[CaseyCarter]

E is a subexpression, not an object

I think we mean to say that t is an lvalue that denotes the result of E; my core-speak is failing me here.

[range.range] range-impl is removed but is still referenced in p2 and p3.

The intent is that these references to range-impl be replaced by references to range. P2 is still a mess, however, since it refers to "The required expressions ranges::begin(std::forward<T>(t)) and ranges::end(std::forward<T>(t)) ..." which need to be changed to "The required expressions ranges::begin(t) and ranges::end(t) ...".

I won't even try to rationalize this rewording as "Editorial".

[jensmaurer]

cv-unqualified or \cv-unqualified?

I think we want "cv-qualified" and "cv-unqualified". We only use \cv{} if it is a placeholder for a (specific) set of cv-qualifiers.

When to use \deflibconcept?

The intent is to use \deflibconcept where we actually show the definition of a library concept (i.e. not in the header synopsis if we have an itemdecl).

The library is inconsistent in its use of \exposconcept v. \tcode{\placeholder

Yes, there are probably still a few issues like this left over. [Update: see #3494]

[burblebee]

@CaseyCarter

I think we mean ...
...
I won't even try to rationalize this rewording as "Editorial".

I've emailed @brevzin and lwgchair for direction on what to do... Would have cc'ed you but don't have your email address :)