bpo-29030: Document interaction between *choices* and *metavar*. (GH-23884)
diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
index 1a298cd..4542961 100644
--- a/Doc/library/argparse.rst
+++ b/Doc/library/argparse.rst
@@ -1152,6 +1152,11 @@
Use of :class:`enum.Enum` is not recommended because it is difficult to
control its appearance in usage, help, and error messages.
+Formatted choices overrides the default *metavar* which is normally derived
+from *dest*. This is usually what you want because the user never sees the
+*dest* parameter. If this display isn't desirable (perhaps because there are
+many choices), just specify an explicit metavar_.
+
required
^^^^^^^^