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### 2207. `basic_string::at` should not have a Requires clause

Section: 21.3.3.6 [string.access] Status: C++14 Submitter: Nevin Liber Opened: 2012-10-26 Last modified: 2016-01-28

Priority: Not Prioritized

View all other issues in [string.access].

View all issues with C++14 status.

Discussion:

`basic_string::at()` has a wide contract and should not have a "Requires" clause on it.

[2013-01-17, Juan Soulie comments]

This issue would also apply to every member function of `basic_string` that throws `out_of_range`, and to some cases where a `length_error` can be thrown.

[2013-03-15 Issues Teleconference]

Moved to Review.

While this could simply move to Ready on inspection, there is concern that this will not be the only such case. Alisdair volunteers to review clause 21/23 for more of such issues for Bristol, and update the proposed resolution as necessary.

[2013-04-18, Bristol]

Proposed resolution:

This wording is relative to N3376.

1. Remove 21.3.3.6 [string.access] p5:

   >     const_reference at(size_type pos) const;
   >     reference at(size_type pos);

   > > -5- Requires: `pos < size()`

   > > -6- Throws: `out_of_range` if `pos >= size()`.

   > > -7- Returns: `operator[](pos)`.