[Bug c++/50431] [C++0x] bug in def array size with a lambda

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50431

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-09-16 13:47:49 UTC ---
(In reply to comment #2)
> BUG1:
>   auto sz = []()->constexpr long { return 100L; };
>   int arr[sz()];
> 
> Why constexpr for lambda won't be compiled? Can i not use auto type for a
> lambda variant?

The closure type's function call operator can be const but not constexpr.
You can use auto for a lambda, you just can't have a constexpr lambda.

Why do you want it to work?  

What advantage is there to using a lambda instead of named function? e.g.

  constexpr long sz() { return 100L; };
  int arr[sz()];