From 490a79e970cae91d1383a9081186b0b809be6da5 Mon Sep 17 00:00:00 2001
From: hauntsaninja <>
Date: Thu, 14 May 2020 00:26:47 -0700
Subject: [PATCH 1/2] test_syntax: add try-except cases that crash with the new
 parser

---
 Lib/test/test_syntax.py | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py
index 06636ae8a149a4..75d754152852e5 100644
--- a/Lib/test/test_syntax.py
+++ b/Lib/test/test_syntax.py
@@ -529,6 +529,31 @@
      ...
    SyntaxError: no binding for nonlocal '_A__x' found
 
+Tests for try-except clauses:
+   >>> try:
+   ...     ...
+   ... except Exception as a.b:
+   ...   pass
+   Traceback (most recent call last):
+     ...
+   SyntaxError: invalid syntax
+
+   >>> try:
+   ...     ...
+   ... except Exception as a[0]:
+   ...   pass
+   Traceback (most recent call last):
+     ...
+   SyntaxError: invalid syntax
+
+   >>> try:
+   ...     ...
+   ... except Exception as (a):
+   ...   pass
+   Traceback (most recent call last):
+     ...
+   SyntaxError: invalid syntax
+
 
 This tests assignment-context; there was a bug in Python 2.5 where compiling
 a complex 'if' (one with 'elif') would fail to notice an invalid suite,

From ff13ce07199b8f879dad69bd81c59c0bfc2f28f6 Mon Sep 17 00:00:00 2001
From: hauntsaninja <>
Date: Thu, 14 May 2020 00:28:03 -0700
Subject: [PATCH 2/2] pegen: make except take a NAME, not a target

---
 Grammar/python.gram  |  2 +-
 Parser/pegen/parse.c | 12 ++++++------
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/Grammar/python.gram b/Grammar/python.gram
index 84c89330e3ee9d..4c4201c6442714 100644
--- a/Grammar/python.gram
+++ b/Grammar/python.gram
@@ -185,7 +185,7 @@ try_stmt[stmt_ty]:
     | 'try' ':' b=block f=finally_block { _Py_Try(b, NULL, NULL, f, EXTRA) }
     | 'try' ':' b=block ex=except_block+ el=[else_block] f=[finally_block] { _Py_Try(b, ex, el, f, EXTRA) }
 except_block[excepthandler_ty]:
-    | 'except' e=expression t=['as' z=target { z }] ':' b=block {
+    | 'except' e=expression t=['as' z=NAME { z }] ':' b=block {
         _Py_ExceptHandler(e, (t) ? ((expr_ty) t)->v.Name.id : NULL, b, EXTRA) }
     | 'except' ':' b=block { _Py_ExceptHandler(NULL, NULL, b, EXTRA) }
 finally_block[asdl_seq*]: 'finally' ':' a=block { a }
diff --git a/Parser/pegen/parse.c b/Parser/pegen/parse.c
index b1b248187ea3ed..f1a0e96b1a5d43 100644
--- a/Parser/pegen/parse.c
+++ b/Parser/pegen/parse.c
@@ -3350,7 +3350,7 @@ try_stmt_rule(Parser *p)
     return _res;
 }
 
-// except_block: 'except' expression ['as' target] ':' block | 'except' ':' block
+// except_block: 'except' expression ['as' NAME] ':' block | 'except' ':' block
 static excepthandler_ty
 except_block_rule(Parser *p)
 {
@@ -3367,7 +3367,7 @@ except_block_rule(Parser *p)
     UNUSED(_start_lineno); // Only used by EXTRA macro
     int _start_col_offset = p->tokens[_mark]->col_offset;
     UNUSED(_start_col_offset); // Only used by EXTRA macro
-    { // 'except' expression ['as' target] ':' block
+    { // 'except' expression ['as' NAME] ':' block
         Token * _keyword;
         Token * _literal;
         asdl_seq* b;
@@ -3378,7 +3378,7 @@ except_block_rule(Parser *p)
             &&
             (e = expression_rule(p))  // expression
             &&
-            (t = _tmp_48_rule(p), 1)  // ['as' target]
+            (t = _tmp_48_rule(p), 1)  // ['as' NAME]
             &&
             (_literal = _PyPegen_expect_token(p, 11))  // token=':'
             &&
@@ -13073,7 +13073,7 @@ _loop1_47_rule(Parser *p)
     return _seq;
 }
 
-// _tmp_48: 'as' target
+// _tmp_48: 'as' NAME
 static void *
 _tmp_48_rule(Parser *p)
 {
@@ -13082,13 +13082,13 @@ _tmp_48_rule(Parser *p)
     }
     void * _res = NULL;
     int _mark = p->mark;
-    { // 'as' target
+    { // 'as' NAME
         Token * _keyword;
         expr_ty z;
         if (
             (_keyword = _PyPegen_expect_token(p, 531))  // token='as'
             &&
-            (z = target_rule(p))  // target
+            (z = _PyPegen_name_token(p))  // NAME
         )
         {
             _res = z;