[class.init] Replace abominable temporary expression wording #4235
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| A temporary expression bound to a reference member in a \grammarterm{mem-initializer} | ||
| A program extending the lifetime of a temporary object | ||
| by binding it to a reference member in a \grammarterm{mem-initializer} | ||
| is ill-formed. |
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Can we phrase this as a regular "shall not" rule, rather than "A program ... is ill-formed"?
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Something like: "A program shall not (attempt to?) extend the lifetime of a temporary object by binding it to a reference member ..."?
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I think it would be better to move this wording into the second set of bullets in [class.temporary]p6. I'm not sure why we moved it out of there to here. |
But the second set of bullets is about when the lifetime extension/shrink doesn't happen and the program is still well-formed. Whilst here the program is ill-formed. |
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@zygoloid: any further thoughts on this? Should we take this to CWG? |
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I still think moving to [class.temporary]p6, so we have all the rules for lifetime-extension in the same place, would make more sense. The status quo is that we say that lifetime is extended in these cases, and then rules elsewhere say that if that happens, the program's ill-formed, which seems both a little too indirect and confusing (until we find it's ill-formed, we need to keep in our minds the idea of a program that performs a lifetime extension that can't possibly work in practice). If we keep it where it is, I still think a "shall not" phrasing would be preferable. If we can't reach consensus, asking CWG for input might help, but I think this is fundamentally editorial. |
tkoeppe
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Finally fixes #1910