[Moved to DR at the October, 2012 meeting.]

Additional note, January, 2012:

An objection has been raised to the proposed resolution on the basis that it unnecessarily weakens the distinction between rvalues and lvalues, making it easier to create dangling references. Its status has therefore been changed back to "review" to allow further discussion.

Proposed resolution (August, 2011):

Change 7.6.1.7 [expr.dynamic.cast] paragraph 6 as follows:

Otherwise, v shall be a pointer to or an lvalue a glvalue of a polymorphic type (11.7.3 [class.virtual]).

7.6.1.7 [expr.dynamic.cast] paragraph 2 allows an expression of any value category when the target type is an rvalue reference. However, paragraph 6 requires that the operand be an lvalue if the runtime check is to be applied. This requirement should presumably be relaxed to require only a glvalue when the target type is an rvalue reference.