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3353. locale's copy assignment operator should return locale&

Section: 30.3.1 [locale] Status: New Submitter: Stephan T. Lavavej Opened: 2019-12-06 Last modified: 2019-12-21

Priority: 3

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Curiously, locale's copy assignment operator currently returns const locale&. As Casey Carter noted in microsoft/STL#268, this is:

We aren't aware of any reason for this to be const. (I observe that this hasn't changed since N1804 on 2005-04-27 and probably goes back to C++98; I suspect that when this was originally specified, copy assignment operators were relatively new, and conventions for them weren't rigorously followed.)

[2019-12-21 Issue Prioritization]

Priority to 3 after reflector discussion based on the observation that we have implementation divergence.

Proposed resolution:

This wording is relative to N4842.

  1. Modify 30.3.1 [locale] as indicated:

    ~locale(); // not virtual
    const locale& operator=(const locale& other) noexcept;
    template<class Facet> locale combine(const locale& other) const;
  2. Modify [locale.cons] as indicated:

    const locale& operator=(const locale& other) noexcept;

    -14- Effects: Creates a copy of other, replacing the current value.

    -15- Returns: *this.