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Re: Defect report: integral-to-boolean conversion in converted constant expressions

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Am 20.10.2011 00:24, schrieb Richard Smith:
>  Hi,
>
>  In both C++98 and C++11, the following code appears to be ill-formed:
>
>      template<bool b>    struct S {};
>      S<0>    s;
>
>  However, EDG, g++ and clang all accept it. The reason this is ill-formed is
>  that the non-type template argument is a converted constant expression of type
>  'bool' (see [temp.arg.nontype]p5), and the second conversion in the implicit
>  conversion sequence is a boolean conversion, which is not allowed in the
>  conversion for a converted constant expression (see [expr.const]p3).
>  Conversions in the other direction (from 'bool' to integer types) are
>  permitted here, since they're integral promotions.
>
>  Suggested resolution: In [expr.const]p3, add "boolean conversions from
>  integral or unscoped enumeration type other than narrowing conversions" to the
>  list of conversions allowed in a converted constant expression.

Forwarded to CWG.

It seems to me that the actual issue is, whether it is clear or not that
[conv.integral] p4 already implies what you are suggesting here.

Greetings from Bremen,

Daniel Krügler



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Defect report: integral-to-boolean conversion in converted       constant expressions "Richard Smith"<richard@metafoo.co.uk> - 2011-10-19 15:24 -0700
  Re: Defect report: integral-to-boolean conversion in converted      constant expressions Daniel Krügler<daniel.kruegler@googlemail.com> - 2011-10-25 09:59 -0700

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