Proposed resolution (September, 2009): Change 7.7 [expr.const] paragraph 2, bullet 4, sub-bullet 1
as indicated: an lvalue-to-rvalue conversion (7.3.2 [conv.lval])
unless it is applied to an lvalue of effective integral or enumeration
type that refers to a non-volatile const variable or static data
member initialized with constant expressions, or ...
N2800 comment
UK 50 According to 7.7 [expr.const] paragraph 2, bullet 4,
sub-bullet 1, a non-volatile const variable or static data member
initialized with constant expressions can be used in an integral
constant expression only if it is “of effective integral
type.” Unscoped enumeration types should also be accepted in
such contexts.