Proposed resolution (approved by CWG 2024-09-27):

Change in 15.1 [cpp.pre] paragraph 2 as follows:

A sequence of preprocessing tokens is only a text-line if it does not begin with a directive-introducing token. [ Example:

  using module = int;
  module i;       // not a text-line and not a control-line
  int foo() {
    return i;
  }

The example is not a valid preprocessing-file. -- end example]