[3.13] gh-137376: Add note on top-level `global` declarations (GH-137707) (#138022)

(cherry picked from commit 9f05f98730bbc36f4ad173845458827c4df879f6)

Co-authored-by: Petr Viktorin <encukou@gmail.com>
Co-authored-by: Brian Schubert <brianm.schubert@gmail.com>

diff --git a/Doc/reference/simple_stmts.rst b/Doc/reference/simple_stmts.rst
index 165436eaa327b439d6fbd121150cb678d57ecada..5a9c398b54ca92ab2b27321aa7adc6dc0e417498 100644 (file)
--- a/Doc/reference/simple_stmts.rst
+++ b/Doc/reference/simple_stmts.rst
@@ -972,10 +972,17 @@ as globals. It would be impossible to assign to a global variable without
 :keyword:`!global`, although free variables may refer to globals without being
 declared global.
 
-The :keyword:`global` statement applies to the entire scope of a function or
-class body. A :exc:`SyntaxError` is raised if a variable is used or
+The :keyword:`!global` statement applies to the entire current scope
+(module, function body or class definition).
+A :exc:`SyntaxError` is raised if a variable is used or
 assigned to prior to its global declaration in the scope.
 
+At the module level, all variables are global, so a :keyword:`!global`
+statement has no effect.
+However, variables must still not be used or
+assigned to prior to their :keyword:`!global` declaration.
+This requirement is relaxed in the interactive prompt (:term:`REPL`).
+
 .. index::
    pair: built-in function; exec
    pair: built-in function; eval