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### 916. Redundant move-assignment operator of `pair` should be removed

Section: 20.4 [pairs] Status: NAD Submitter: Daniel Krügler Opened: 2008-10-04 Last modified: 2016-01-28

Priority: Not Prioritized

View all other issues in [pairs].

View all issues with NAD status.

Discussion:

see also 917.

The current WP provides the following assignment operators for `pair` in 20.4 [pairs]/1:

1.     template<class U , class V>
       requires HasAssign<T1, const U&> && HasAssign<T2, const V&>
       pair& operator=(const pair<U , V>& p);

2.     requires MoveAssignable<T1> && MoveAssignable<T2> pair& operator=(pair&& p );

3.     template<class U , class V>
       requires HasAssign<T1, RvalueOf<U>::type> && HasAssign<T2, RvalueOf<V>::type>
       pair& operator=(pair<U , V>&& p);

It seems that the functionality of (2) is completely covered by (3), therefore (2) should be removed.

[ Batavia (2009-05): ]

> Bill believes the extra assignment operators are necessary for resolving ambiguities, but that does not mean it needs to be part of the specification.

> Move to Open. We recommend this be looked at in the context of the ongoing work related to the pair templates.

[ 2009-07 Frankfurt: ]

> Leave this open pending the removal of concepts from the WD.

[ 2009-10 Santa Cruz: ]

> Mark as NAD, see issue 801.

Proposed resolution:

1. In 20.4 [pairs] p. 1, class `pair` and just before p. 13 remove the declaration:

   >     requires MoveAssignable<T1> && MoveAssignable<T2> pair& operator=(pair&& p );

2. Remove p.13+p.14