2105. Inconsistent requirements on const_iterator's value_type

Section: 23.2.2 [container.requirements.general] Status: C++14 Submitter: Jeffrey Yasskin Opened: 2011-11-28 Last modified: 2016-01-28

Priority: Not Prioritized

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Discussion:

In the FDIS, Table 96 specifies X::const_iterator as a "constant iterator type whose value type is T". However, Table 97 specifies X::const_reverse_iterator as an "iterator type whose value type is const T" and which is defined as reverse_iterator<const_iterator>. But reverse_iterator::value_type is just "typename iterator_traits<Iterator>::value_type" 24.5.1.2 [reverse.iterator], so const_iterator and const_reverse_iterator must have the same value_type.

The resolution to issue 322 implies that const_reverse_iterator should change.

[2012, Kona]

Move to Ready.

[2012, Portland: applied to WP]

Proposed resolution:

This wording is relative to the FDIS.

Change Table 97 — "Reversible container requirements" as indicated

Table 97 — Reversible container requirements
Expression Return type Assertion/note pre-/post-condition Complexity
X::reverse_-
iterator 		iterator type whose value type
is T 		reverse_iterator<iterator> compile time
X::const_-
reverse_-
iterator 		constant iterator type whose value type
is const T 		reverse_iterator<const_iterator> compile time