Proposed resolution (approved by CWG 2023-10-06):

1. Change in 7.7 [expr.const] paragraph 19 as follows:

   [Note 11: Except for a static_assert-message, a A manifestly constant-evaluated expression is evaluated even in an unevaluated operand (7.2.3 [expr.context]). —end note]

2. Change the grammar in 9.1 [dcl.pre] as follows:

   static_assert-message:
     unevaluated-string
     conditional-expression constant-expression
   

3. Change in 9.1 [dcl.pre] bullet 11.2 as follows:

   • ...
   • if the static_assert-message is a conditional-expression constant-expression M, ...