From 50c0a22bc36deb0d667f9e1506b921a791d93e48 Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Thu, 22 Sep 2022 11:18:02 -0700
Subject: [PATCH] gh-96397: Document that keywords in calls need not be
 identifiers (GH-96393)

This represents the official SC stance, see
https://github.com/python/steering-council/issues/142GH-issuecomment-1252172695
(cherry picked from commit 9d432b4a181cd42017699de4354e7b36c5b87d88)

Co-authored-by: Jeff Allen <ja.py@farowl.co.uk>
---
 Doc/reference/expressions.rst | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst
index 4b8ceab5167dbc..6b5e0e1628f143 100644
--- a/Doc/reference/expressions.rst
+++ b/Doc/reference/expressions.rst
@@ -1054,10 +1054,20 @@ used in the same call, so in practice this confusion does not often arise.
 
 If the syntax ``**expression`` appears in the function call, ``expression`` must
 evaluate to a :term:`mapping`, the contents of which are treated as
-additional keyword arguments.  If a keyword is already present
-(as an explicit keyword argument, or from another unpacking),
+additional keyword arguments. If a parameter matching a key has already been
+given a value (by an explicit keyword argument, or from another unpacking),
 a :exc:`TypeError` exception is raised.
 
+When ``**expression`` is used, each key in this mapping must be
+a string.
+Each value from the mapping is assigned to the first formal parameter
+eligible for keyword assignment whose name is equal to the key.
+A key need not be a Python identifier (e.g. ``"max-temp °F"`` is acceptable,
+although it will not match any formal parameter that could be declared).
+If there is no match to a formal parameter
+the key-value pair is collected by the ``**`` parameter, if there is one,
+or if there is not, a :exc:`TypeError` exception is raised.
+
 Formal parameters using the syntax ``*identifier`` or ``**identifier`` cannot be
 used as positional argument slots or as keyword argument names.