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[basic.def.odr] Validity of duplicate enumerators CWG2530 #4788

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xmh0511 opened this issue Aug 2, 2021 · 3 comments
Open

[basic.def.odr] Validity of duplicate enumerators CWG2530 #4788

xmh0511 opened this issue Aug 2, 2021 · 3 comments
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cwg Issue must be reviewed by CWG. not-editorial Issue is not deemed editorial; the editorial issue is kept open for tracking.

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@xmh0511
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xmh0511 commented Aug 2, 2021 •
edited 

enum class A{
    a = 0,
    a = 1
};

[basic#pre-5.12] specifies that an enumerator-definition is a declaration. According to [basic.link#8], they declare the same entity. For this example, the major implementations report that "redefinition of enumerator 'a'"., however, [basic.def.odr#1] didn't mention enumerators

No translation unit shall contain more than one definition of any variable, function, class type, enumeration type, template, default argument for a parameter (for a function in a given scope), or default template argument.

Does the rule omit such a case? Also, ask the clarification of this case in this issue.
@xmh0511 xmh0511 changed the title The Odr restrictions didn't apply to enumerators The odr restrictions didn't apply to enumerators Aug 2, 2021
@jensmaurer
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jensmaurer commented Aug 20, 2021 •
edited

There's also a question about

enum A { x };
enum B { x };

http://lists.isocpp.org/core/2021/08/11347.php

@jensmaurer jensmaurer changed the title The odr restrictions didn't apply to enumerators [basic.def.odr] Validity of duplicate enumerators Aug 20, 2021
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The first case is probably a defect.
The second case is handled by [basic.scope.scope] p4

The name ::x "is bound to two declarations that potentially conflict",
because the declarations for A::x and B::x "cause their shared name to
denote different entities".

@jensmaurer jensmaurer added cwg Issue must be reviewed by CWG. not-editorial Issue is not deemed editorial; the editorial issue is kept open for tracking. labels Aug 20, 2021
@jensmaurer jensmaurer changed the title [basic.def.odr] Validity of duplicate enumerators [basic.def.odr] Validity of duplicate enumerators CWG2530 Feb 19, 2022
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See CWG2530

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