Change error type when constants are used as an identifier

Author: StanFromIreland

Lib/test/test_ast/test_ast.py

@@ -954,7 +954,7 @@ def test_constant_as_unicode_name(self):
             ("None", b"N\xc2\xbane"),
         ]
         for constant in constants:
-            with self.assertRaisesRegex(ValueError,
+            with self.assertRaisesRegex(SyntaxError,
                 f"identifier field can't represent '{constant[0]}' constant"):
                 ast.parse(constant[1], mode="eval")
 

Misc/NEWS.d/next/Core_and_Builtins/2026-03-09-17-19-04.gh-issue-145675.9YPpYi.rst

@@ -0,0 +1,2 @@
+Raise :exc:`SyntaxError` when constants ``True``, ``False`` or ``None`` are
+used as an identifier after NFKC normalization.

Parser/pegen.c

@@ -539,7 +539,7 @@ _PyPegen_new_identifier(Parser *p, const char *n)
     };
     for (int i = 0; forbidden[i] != NULL; i++) {
         if (_PyUnicode_EqualToASCIIString(id, forbidden[i])) {
-            PyErr_Format(PyExc_ValueError,
+            RAISE_SYNTAX_ERROR(
                          "identifier field can't represent '%s' constant",
                          forbidden[i]);
             Py_DECREF(id);