Can you please give a code example and state what you think is the desired
behavior for it?

On Sun, Nov 30, 2025 at 5:33 AM mauro russo via Std-Discussion <
std-discussion_at_[hidden]> wrote:

> hello,
>
> waiting for any answer on this topic.
>
> Let me ignore previous messages on it.
>
> I am suggesting to review
> https://eel.is/c++draft/expr.prim.lambda.capture#14.1
> which reads
> "... if m1 is not mutable, the non-static data member is considered to be
> const-qualified."
>
> IMO, this wording rules out the case of explicit object parameter deduced
> as non-const-qualified closure type (or its derivation, as well as
> references
> to such types... i.e., the same listed for the case of non-empty captures
> in
> https://eel.is/c++draft/expr.prim.lambda#closure-6),
>
> even because the term 'mutable' in the reported wording "is not mutable" is
> formatted to indicate the language keyword, isn't it ?
> Also, no general definition of "mutable" lambda is provided to include the
> case of explicit object parameter.
>
> Likely, a possible solution without introducing a generalized concept of
> mutable
> lambda, might be to lengthen the reported wording with something like:
> ", unless the explicit object parameter, if any, is deduced as non
> const-qualified type (or reference to)."
> where I supposed that it's not really needed to explicit the list of
> allowed types,
> since the discussed wording is in a context with non-empty capture,
> necessarily
> leading to restrict the deduced types to the list of the aforementioned
> clause #6.
>
> Kind regards.
> Mauro.
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-- 
*Brian Bi*