On Sat, 12 Sep 00:01:00 GMT 2026,
"Ivan Sokolov" <[email protected]> wrote:
> The standard [expr.prim.lambda.closure#12] seems silent on the matter,
> and the above examples make me think this paragraph was simply
> forgotten when wording was modified to account for constraints.
On a second look, it seems Clang and GCC both do another useful
deviation from that the standard.
The paragraph says that the return value of the conversion operator
should be as if decltype(/*operator() call*/). However, when a trailing
return type is present, as it is in my example, we are able to bypass
the decltype() and use the trailing return type as it is spelled, which
allows us to deduce the template parameter on the conversion even
though it is not deducible on the call operator.
int(*pfn)() = []<typename T>()->T { return T{}; };
// clang and gcc both accept this, in spite of the standard
So perhaps that one paragraph is in need of a bigger overhaul :)
