[temp.explicit] Fix unclear reference to elaborated-type-specifier #3872
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source/templates.tex
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| If the explicit instantiation is for a class or member class, the \grammarterm{declaration} | ||
| shall consist of a single \grammarterm{elaborated-type-specifier} that includes a | ||
| \grammarterm{simple-template-id}; otherwise, the \grammarterm{declaration} |
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I think the "shall consist of a single" part of this rule belongs in [temp.pre]p5:
When such a declaration is used to declare a class template or class template specialization, no declarator is permitted.
As written, this doesn't seem quite right: requiring the declaration to consist of only an elaborated-type-specifier would disallow attributes.
But there's something really fishy about the rules here in general: we're starting (in both [temp.pre] and here) by assuming we know whether we're explicitly instantiating a class or something else, and there's no rules to say when we are doing so.
What we really mean is something like: if there is no declarator, then the template, template specialization, or explicit instantiation declaration is declaring a class or class template, and the decl-specifier-seq shall contain a single defining-type-specifier that is either a class-specifier, an enum-specifier, or an elaborated-type-specifier. And for an explicit instantiation, it shall be an elaborated-type-specifier that either includes a simple-template-id or whose nested-name-specifier includes a simple-template-id.
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And please fix the Travis failure. |
sdkrystian
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@zygoloid I added a commit which specifies what a template actually declares in [temp.pre]... however, this is a little difficult without being very wordy. |
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The wording changes here are substantial; let's have CWG give them a look over before we apply them. |
jensmaurer
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Could you please rebase? |
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I'll have it rebased tomorrow |
It is unclear what elaborated-type-specifier we are referring to, and the current wording does not do a good job specifying what form the explicit instantiation should take.