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1020. Restore aligned_union

Section: 21.3.8.7 [meta.trans.other] Status: NAD Submitter: Alisdair Meredith Opened: 2009-03-11 Last modified: 2016-01-28

Priority: Not Prioritized

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Discussion:

Addresses UK 204 [CD1]

It is not possible to create a variant union based on a parameter pack expansion, e.g. to implement a classic discriminated union template.

Original proposed resolutuion:

Restore aligned_union template that was removed by LWG issue 856⁽ⁱ⁾.

[ Summit: ]

Agree. The need for aligned_union is compelling enough to reinstate.

[ Post Summit, Alisdair adds: ]

Paper N2843 proposes an extension to the [[align]] attribute that further diminishes the need for this template. Recommend NAD.

[ 2009-10 Santa Cruz: ]

Mark NAD as suggested.

Proposed resolution: