Proposed resolution:

This wording is relative to N4606.

This reverts LWG 659.

1. Remove the note in paragraph 1 of [istreambuf.iterator]:

   The class template istreambuf_iterator defines an input iterator (24.2.3) that reads successive characters from the streambuf for which it was constructed. operator* provides access to the current input character, if any. [Note: operator-> may return a proxy. — end note] Each time operator++ is evaluated, the iterator advances to the next input character. […]

2. Remove the member from the class synopsis in [istreambuf.iterator]:

   charT operator*() const;
   pointer operator->() const;
   istreambuf_iterator& operator++();
   proxy operator++(int);
   

[ Issues Telecon 16-Dec-2016 ]

Move to Review

[ 2016-11-08, Jonathan comments and suggests wording ]

There is no good option here, and implementations either return nullptr, or return the address of a temporary, or don't even provide the member at all. We took polls to decide whether to remove istreambuf_iterator::operator->, or specify it to return nullptr, and the preferred option was to remove it. It was noted that in the Ranges TS input iterators no longer require operator-> anyway, and the library never tries to use it.

Addresses GB 59

There is no specification for istreambuf_iterator::operator->. This operator appears to have been added for C++11 by LWG issue 659, which gave the signature, but also lacked specification.