This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 114a. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.
2024-04-18
[Voted into the WP at the March, 2011 meeting.]
It is not clear what happens when a program violates the limits on constexpr function recursion in a context that does not require a constant expression. For example,
constexpr int f(int i) { return f(i); }
const int i = f(1); // error, undefined behavior, or dynamic initialization?
(Presumably the “within its resource limits” caveat of 4.1 [intro.compliance] paragraph 2 would effectively result in undefined behavior in a context that required a constant expression.)
Notes from the November, 2010 meeting:
The CWG was of mixed opinion as to whether an infinite recursion in a constexpr function should be ill-formed or simply render an expression non-constant.
Proposed resolution (January, 2011):
Add the following bullet in 7.7 [expr.const] paragraph 2:
an invocation of a constexpr function or a constexpr constructor that would exceed the implementation-defined recursion limit (see annex Clause Annex B [implimits]);