bpo-46004: Fix error location for loops with invalid targets (GH-29959)

Author: pablogsal

Lib/test/test_exceptions.py

@@ -234,6 +234,7 @@ def testSyntaxErrorOffset(self):
         check("ages = {'Alice'=22, 'Bob'=23}", 1, 16)
         check('match ...:\n    case {**rest, "key": value}:\n        ...', 2, 19)
         check("[a b c d e f]", 1, 2)
+        check("for x yfff:", 1, 7)
 
         # Errors thrown by compile.c
         check('class foo:return 1', 1, 11)

Misc/NEWS.d/next/Core and Builtins/2021-12-07-11-24-24.bpo-46004.TTEU1p.rst

@@ -0,0 +1,2 @@
+Fix the :exc:`SyntaxError` location for errors involving for loops with
+invalid targets. Patch by Pablo Galindo

Parser/pegen.h

@@ -227,8 +227,9 @@ _RAISE_SYNTAX_ERROR_INVALID_TARGET(Parser *p, TARGETS_TYPE type, void *e)
             msg,
             _PyPegen_get_expr_name(invalid_target)
         );
+        return RAISE_SYNTAX_ERROR_KNOWN_LOCATION(invalid_target, "invalid syntax");
     }
-    return RAISE_SYNTAX_ERROR("invalid syntax");
+    return NULL;
 }
 
 // Action utility functions