Proposed resolution (approved by CWG 2023-06-15):

Change in 9.3.4.3 [dcl.ref] paragraph 1 as follows:

A declarator that specifies Forming the type “reference to cv void” is ill-formed.

[Accepted as a DR at the June, 2023 meeting.]

9.3.4.3 [dcl.ref] paragraph 1 specifies:

A declarator that specifies the type “reference to cv void” is ill-formed.

A declarator does not contain the leading decl-specifier-seq of a declaration, so the following example is not covered by the prohibition:

  void f(void& x);