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[dcl.fct.def.coroutine] p13 A valid reference type is not cv-qualified #4868

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xmh0511 opened this issue Sep 6, 2021 · 4 comments
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[dcl.fct.def.coroutine] p13 A valid reference type is not cv-qualified #4868

xmh0511 opened this issue Sep 6, 2021 · 4 comments

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@xmh0511
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xmh0511 commented Sep 6, 2021

When a coroutine is invoked, after initializing its parameters ([expr.call]), a copy is created for each coroutine parameter. For a parameter of type cv T, the copy is a variable of type cv T with automatic storage duration that is direct-initialized from an xvalue of type T referring to the parameter.

When the parameter has a reference type, cv T is the wrong exposition. Maybe, we could say

When a coroutine is invoked, after initializing its parameters ([expr.call]), a copy is created for each coroutine parameter. For a parameter of type cv T or of type reference to cv T, the copy is a variable of the corresponding type with automatic storage duration that is direct-initialized from an xvalue of type T referring to the parameter.
@xmh0511 xmh0511 changed the title [dcl.fct.def.coroutine] p13 A valid reference type has not cv qualification [dcl.fct.def.coroutine] p13 A valid reference type is not cv-qualified Sep 6, 2021
@jensmaurer
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If T is a reference type, then "cv" is simply empty (because references cannot be cv-qualified). I'm not seeing a problem here.

@xmh0511
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xmh0511 commented Sep 6, 2021 •
edited

If T is an lvalue reference type, how could an expression be an xvalue of an lvalue reference type? Since [expr.type] p1 says

If an expression initially has the type “reference to T” ([dcl.ref], [dcl.init.ref]), the type is adjusted to T prior to any further analysis.

Instead, we say "xvalue of type T" where T may reference type in [dcl.fct.coroutine] p13, they seem to conflict.

@jensmaurer
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That's a valid point, but unrelated to the subject of this issue, which talks about cv-qualification.

@xmh0511
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xmh0511 commented Sep 6, 2021

Well, actually this issue has two concerns here. I will post a new issue about the second one. This should be closed.

@xmh0511 xmh0511 closed this as completed Sep 6, 2021
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@xmh0511 @jensmaurer