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### 2830. `insert_return_type` is only defined for containers with unique keys

Section: 24.2.7 [associative.reqmts], 24.2.8 [unord.req] Status: Resolved Submitter: Daniel James Opened: 2016-11-24 Last modified: 2020-09-06

Priority: Not Prioritized

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Discussion:

The requirements for associative and unordered associative containers list `insert_return_type` for all containers, but looking at the class description in 24.4.4.1 [map.overview], 24.4.5.1 [multimap.overview] etc. it's only defined for containers with unique keys. Jonathan Wakely pointed out that this depends on the resolution of LWG 2772, which might remove `insert_return_type` completely.

A possible resolution would be to put in 24.2.7 [associative.reqmts]: '`insert_return_type` (`map` and `set` only)' and in 24.2.8 [unord.req]: '`insert_return_type` (`unordered_map` and `unordered_set` only)'. Or maybe something like '(containers with unique keys only)'.

[Issues Telecon 16-Dec-2016]

Resolved by adoption of P0508R0.

Proposed resolution: