Fix error for augassign

Author: pablogsal

Grammar/python.gram

@@ -641,20 +641,13 @@ invalid_assignment:
     | a=expression ':' expression ['=' annotated_rhs] {
         RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "illegal target for annotation") }
     | a=star_expressions '=' (yield_expr | star_expressions) {
-        RAISE_SYNTAX_ERROR_KNOWN_LOCATION( 
-            _PyPegen_get_invalid_target(a), 
-            "cannot assign to %s", _PyPegen_get_expr_name(_PyPegen_get_invalid_target(a))
-        )}
-    | a=expression augassign (yield_expr | star_expressions) {
-        RAISE_SYNTAX_ERROR_KNOWN_LOCATION( 
-            _PyPegen_get_invalid_target(a), 
-            "cannot assign to %s", _PyPegen_get_expr_name(_PyPegen_get_invalid_target(a))
-        )}
+        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
+            _PyPegen_get_invalid_target(a),
+            "cannot assign to %s", _PyPegen_get_expr_name(_PyPegen_get_invalid_target(a))) }
+    | a=expression augassign (yield_expr | star_expressions) { _PyPegen_raise_syntax_error_for_augassign(p, a) }
     | a=star_expressions augassign (yield_expr | star_expressions) {
-        RAISE_SYNTAX_ERROR_KNOWN_LOCATION( 
-            a, 
-            "illegal expression for augmented assignment"
-        )}
+        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "illegal expression for augmented assignment") }
+ 
 invalid_block:
     | NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block") }
 invalid_comprehension:

Lib/test/test_syntax.py

@@ -138,15 +138,15 @@
 
 >>> a, b += 1, 2
 Traceback (most recent call last):
-SyntaxError: invalid syntax
+SyntaxError: illegal expression for augmented assignment
 
 >>> (a, b) += 1, 2
 Traceback (most recent call last):
-SyntaxError: cannot assign to tuple
+SyntaxError: illegal expression for augmented assignment
 
 >>> [a, b] += 1, 2
 Traceback (most recent call last):
-SyntaxError: cannot assign to list
+SyntaxError: illegal expression for augmented assignment
 
 From compiler_complex_args():
 

Parser/pegen/parse.c

@@ -10878,7 +10878,7 @@ invalid_assignment_rule(Parser *p)
             (_tmp_129_var = _tmp_129_rule(p))  // yield_expr | star_expressions
         )
         {
-            _res = RAISE_SYNTAX_ERROR_KNOWN_LOCATION ( _PyPegen_get_invalid_target ( a ) , "cannot assign to %s" , _PyPegen_get_expr_name ( _PyPegen_get_invalid_target ( a ) ) );
+            _res = _PyPegen_raise_syntax_error_for_augassign ( p , a );
             if (_res == NULL && PyErr_Occurred()) {
                 p->error_indicator = 1;
                 return NULL;

Parser/pegen/pegen.c

@@ -2093,4 +2093,18 @@ _PyPegen_get_invalid_target(expr_ty e)
         default:
             return e;
     }
-}
+}
+
+void *
+_PyPegen_raise_syntax_error_for_augassign(Parser *p, expr_ty e) {
+    expr_ty invalid_target = _PyPegen_get_invalid_target(e);
+
+    if (invalid_target != NULL) {
+        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(invalid_target,
+        "cannot assign to %s", _PyPegen_get_expr_name(invalid_target));
+    } else {
+        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(e, "illegal expression for augmented assignment");
+    }
+    return NULL;
+}
+

Parser/pegen/pegen.h

@@ -263,7 +263,7 @@ mod_ty _PyPegen_make_module(Parser *, asdl_seq *);
 // Error reporting helpers
 
 expr_ty _PyPegen_get_invalid_target(expr_ty e);
-
+void *_PyPegen_raise_syntax_error_for_augassign(Parser *p, expr_ty e);
 
 void *_PyPegen_parse(Parser *);