[expr.const] P2686R4 made it less clear that a prvalue constant expression must have an object type

[frederick-vs-ja]

In C++23, it seemed clear to me that a prvalue constant expression was required to have an object type, because N4950 [expr.const] p13 explicitly listed permitted cases for various object types.

However, after P2686R4, [expr.const] p22 doesn't seem to require object types, and void expressions are arguably accepted. At least, a prvalue of an empty class type and a void prvalue don't seem distinguishable.

Should we clarify the wording to say a prvalue constant expression must have an object type, or, conversely, a void expression can be a prvalue constant expression?

[jensmaurer]

A "constant expression" is a semantic requirement of the environment where it appears, e.g. in an array bound or similar. In which case would a non-object constant expression be acceptable / required to start with?