May 17, 2025 · May 15, 2025
diff --git a/Grammar/python.gram b/Grammar/python.gram
        RAISE_SYNTAX_ERROR_STARTING_FROM(a, "multiple exception types must be parenthesized when using 'as'") }
    | a='except' expression ['as' NAME ] NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
    | a='except' NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
    | 'except' expression 'as' a=expression {
    | 'except' expression 'as' a=expression':' block{
        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
            a, "cannot use except statement with %s", _PyPegen_get_expr_name(a)) }
 invalid_except_star_stmt:
    | 'except' '*' a=expression ',' expressions 'as' NAME  ':' {
        RAISE_SYNTAX_ERROR_STARTING_FROM(a, "multiple exception types must be parenthesized when using 'as'") }
    | a='except' '*' expression ['as' NAME ] NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
    | a='except' '*' (NEWLINE | ':') { RAISE_SYNTAX_ERROR("expected one or more exception types") }
    | 'except' '*' expression 'as' a=expression {
    | 'except' '*' expression 'as' a=expression':' block{
        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
            a, "cannot use except* statement with %s", _PyPegen_get_expr_name(a)) }
 invalid_finally_stmt:
diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py
   Traceback (most recent call last):
   SyntaxError: cannot use except* statement with literal

 Regression tests for gh-133999:

   >>> try: pass
   ... except TypeError as name: raise from None
   Traceback (most recent call last):
   SyntaxError: invalid syntax

   >>> try: pass
   ... except* TypeError as name: raise from None
   Traceback (most recent call last):
   SyntaxError: invalid syntax

   >>> match 1:
   ...     case 1 | 2 as abc: raise from None
   Traceback (most recent call last):
   SyntaxError: invalid syntax

 Ensure that early = are not matched by the parser as invalid comparisons
   >>> f(2, 4, x=34); 1 $ 2
   Traceback (most recent call last):
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-05-15-11-38-16.gh-issue-133999.uBZ8uS.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-05-15-11-38-16.gh-issue-133999.uBZ8uS.rst
 Fix :exc:`SyntaxError` regression in :keyword:`except` parsing after
 :gh:`123440`.
diff --git a/Parser/parser.c b/Parser/parser.c
Original file line number	Diff line number	Diff line change
Expand Up		@@ -1418,15 +1418,15 @@ invalid_except_stmt:
		RAISE_SYNTAX_ERROR_STARTING_FROM(a, "multiple exception types must be parenthesized when using 'as'") }
		\| a='except' expression ['as' NAME ] NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
		\| a='except' NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
		\| 'except' expression 'as' a=expression {
		\| 'except' expression 'as' a=expression':' block{
		RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
		a, "cannot use except statement with %s", _PyPegen_get_expr_name(a)) }
		invalid_except_star_stmt:
		\| 'except' '*' a=expression ',' expressions 'as' NAME ':' {
		RAISE_SYNTAX_ERROR_STARTING_FROM(a, "multiple exception types must be parenthesized when using 'as'") }
		\| a='except' '*' expression ['as' NAME ] NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
		\| a='except' '*' (NEWLINE \| ':') { RAISE_SYNTAX_ERROR("expected one or more exception types") }
		\| 'except' '*' expression 'as' a=expression {
		\| 'except' '*' expression 'as' a=expression':' block{
		RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
		a, "cannot use except* statement with %s", _PyPegen_get_expr_name(a)) }
		invalid_finally_stmt:
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -1431,6 +1431,23 @@
		Traceback (most recent call last):
		SyntaxError: cannot use except* statement with literal

		Regression tests for gh-133999:

		>>> try: pass
		... except TypeError as name: raise from None
		Traceback (most recent call last):
		SyntaxError: invalid syntax

		>>> try: pass
		... except* TypeError as name: raise from None
		Traceback (most recent call last):
		SyntaxError: invalid syntax

		>>> match 1:
		... case 1 \| 2 as abc: raise from None
		Traceback (most recent call last):
		SyntaxError: invalid syntax

		Ensure that early = are not matched by the parser as invalid comparisons
		>>> f(2, 4, x=34); 1 $ 2
		Traceback (most recent call last):
Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Fix :exc:`SyntaxError` regression in :keyword:`except` parsing after
		:gh:`123440`.