From an email to cxxeditor@:

In subclause 5.16 [expr.cond] paragraph 3:

Each bullet in the following is probably meant to be exclusive of the others. The third bullet should use "prvalue" instead of "rvalue".

• If E2 is an lvalue: E1 can be converted to match E2 if E1 can be implicitly converted (Clause 4) to the type "lvalue reference to T2", subject to the constraint that in the conversion the reference must bind directly (8.5.3) to an lvalue.
• If E2 is an xvalue: E1 can be converted to match E2 if E1 can be implicitly converted to the type "rvalue reference to T2", subject to the constraint that the reference must bind directly.
• If E2 is an rvaluea prvalue or if neither of the conversions above can be done and at least one of the operands has (possibly cv-qualified) class type

Mike Miller confirmed as editorial.