[cfe-commits] [PATCH] Suggested rewording for lamba return values

[Richard Smith]

On Tue, May 22, 2012 at 6:54 PM, Aaron Ballman <aaron at aaronballman.com>wrote:

> When a lambda expression omits the return type information, the
> standard requires the lambda statement body to be a single return
> statement.  However, as a language extension, we (and several other
> compilers) support determining the return type if all of the
> function's return types agree.
>
> The problem is, the wording for the warning we emit is a bit difficult
> to parse.  It's a semantically correct statement, but it's not
> immediately obvious what the problem is or how to rectify it.
> Consider:
>
> auto i = []() { static const int foo = 12; return &foo; }();
>
> This will emit a diagnostic that says "C++11 requires lambda with
> omitted result type to consist of a single return statement" --
> however, a likely initial response to this is "but I do only have a
> single return statement!"
>
> This patch rewords the diagnostic to be a bit more clear (hopefully):
> "C++11 requires a lambda expression with omitted result type to
> consist solely of a return statement"
>
> Thoughts?


I would be in favor of removing the warning entirely, now that Clang 3.1
has shipped. The C++ core working group has already agreed that this should
be allowed. It's currently under consideration by the evolution working
group, whom I think are unlikely to say no -- and if they do, we will have
time to react before 3.2 is released.
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