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Author: pablogsal

Grammar/python.gram

@@ -778,8 +778,8 @@ invalid_named_expression:
             a, "cannot use assignment expressions with %s", _PyPegen_get_expr_name(a)) }
     | a=NAME b='=' bitwise_or !('='|':='|',') {
         RAISE_SYNTAX_ERROR_KNOWN_LOCATION(b, "invalid syntax. Maybe you meant '==' or ':=' instead of '='?") }
-    | !(list|tuple) a=bitwise_or b='=' bitwise_or !('='|':='|',') {
-        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(b, "cannot assign to %s. Maybe you meant '==' instead of '='?",
+    | !(list|tuple|genexp|'True'|'None'|'False') a=bitwise_or b='=' bitwise_or !('='|':='|',') {
+        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(b, "cannot assign to %s here. Maybe you meant '==' instead of '='?",
                                           _PyPegen_get_expr_name(a)) }
 
 invalid_assignment:

Lib/test/test_cmd_line_script.py

@@ -600,7 +600,7 @@ def test_syntaxerror_unindented_caret_position(self):
             script_name = _make_test_script(script_dir, 'script', script)
             exitcode, stdout, stderr = assert_python_failure(script_name)
             text = io.TextIOWrapper(io.BytesIO(stderr), 'ascii').read()
-            # Confirm that the caret is located under the first 1 character
+            # Confirm that the caret is located under the '=' sign
             self.assertIn("\n    1 + 1 = 2\n          ^\n", text)
 
     def test_syntaxerror_indented_caret_position(self):

Lib/test/test_fstring.py

@@ -990,7 +990,7 @@ def test_conversions(self):
                              ])
 
     def test_assignment(self):
-        self.assertAllRaise(SyntaxError, r'invalid syntax\.',
+        self.assertAllRaise(SyntaxError, r'invalid syntax',
                             ["f'' = 3",
                              "f'{0}' = x",
                              "f'{x}' = x",

Lib/test/test_generators.py

@@ -2013,7 +2013,7 @@ def printsolution(self, x):
 >>> def f(): (yield bar) = y
 Traceback (most recent call last):
   ...
-SyntaxError: cannot assign to yield expression. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to yield expression here. Maybe you meant '==' instead of '='?
 
 >>> def f(): (yield bar) += y
 Traceback (most recent call last):

Lib/test/test_genexps.py

@@ -153,7 +153,7 @@
     >>> (y for y in (1,2)) = 10
     Traceback (most recent call last):
        ...
-    SyntaxError: cannot assign to generator expression. Maybe you meant '==' instead of '='?
+    SyntaxError: cannot assign to generator expression
 
     >>> (y for y in (1,2)) += 10
     Traceback (most recent call last):

Lib/test/test_syntax.py

@@ -33,15 +33,15 @@
 
 >>> None = 1
 Traceback (most recent call last):
-SyntaxError: cannot assign to None. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to None
 
 >>> obj.True = 1
 Traceback (most recent call last):
 SyntaxError: invalid syntax
 
 >>> True = 1
 Traceback (most recent call last):
-SyntaxError: cannot assign to True. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to True
 
 >>> (True := 1)
 Traceback (most recent call last):
@@ -61,7 +61,7 @@
 
 >>> f() = 1
 Traceback (most recent call last):
-SyntaxError: cannot assign to function call. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to function call here. Maybe you meant '==' instead of '='?
 
 >>> yield = 1
 Traceback (most recent call last):
@@ -73,27 +73,27 @@
 
 >>> a + 1 = 2
 Traceback (most recent call last):
-SyntaxError: cannot assign to expression. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to expression here. Maybe you meant '==' instead of '='?
 
 >>> (x for x in x) = 1
 Traceback (most recent call last):
-SyntaxError: cannot assign to generator expression. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to generator expression
 
 >>> 1 = 1
 Traceback (most recent call last):
-SyntaxError: cannot assign to literal. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to literal here. Maybe you meant '==' instead of '='?
 
 >>> "abc" = 1
 Traceback (most recent call last):
-SyntaxError: cannot assign to literal. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to literal here. Maybe you meant '==' instead of '='?
 
 >>> b"" = 1
 Traceback (most recent call last):
-SyntaxError: cannot assign to literal. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to literal here. Maybe you meant '==' instead of '='?
 
 >>> ... = 1
 Traceback (most recent call last):
-SyntaxError: cannot assign to Ellipsis. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to Ellipsis here. Maybe you meant '==' instead of '='?
 
 >>> `1` = 1
 Traceback (most recent call last):
@@ -465,7 +465,7 @@
 # SyntaxError: expression cannot contain assignment, perhaps you meant "=="?
 # >>> f(True=2)
 # Traceback (most recent call last):
-# SyntaxError: cannot assign to True. Maybe you meant '==' instead of '='?
+# SyntaxError: cannot assign to True here. Maybe you meant '==' instead of '='?
 >>> f(__debug__=1)
 Traceback (most recent call last):
 SyntaxError: cannot assign to __debug__
@@ -684,15 +684,15 @@
    ...   pass
    Traceback (most recent call last):
      ...
-   SyntaxError: cannot assign to function call. Maybe you meant '==' instead of '='?
+   SyntaxError: cannot assign to function call here. Maybe you meant '==' instead of '='?
 
    >>> if 1:
    ...   pass
    ... elif 1:
    ...   x() = 1
    Traceback (most recent call last):
      ...
-   SyntaxError: cannot assign to function call. Maybe you meant '==' instead of '='?
+   SyntaxError: cannot assign to function call here. Maybe you meant '==' instead of '='?
 
    >>> if 1:
    ...   x() = 1
@@ -702,7 +702,7 @@
    ...   pass
    Traceback (most recent call last):
      ...
-   SyntaxError: cannot assign to function call. Maybe you meant '==' instead of '='?
+   SyntaxError: cannot assign to function call here. Maybe you meant '==' instead of '='?
 
    >>> if 1:
    ...   pass
@@ -712,7 +712,7 @@
    ...   pass
    Traceback (most recent call last):
      ...
-   SyntaxError: cannot assign to function call. Maybe you meant '==' instead of '='?
+   SyntaxError: cannot assign to function call here. Maybe you meant '==' instead of '='?
 
    >>> if 1:
    ...   pass
@@ -722,7 +722,7 @@
    ...   x() = 1
    Traceback (most recent call last):
      ...
-   SyntaxError: cannot assign to function call. Maybe you meant '==' instead of '='?
+   SyntaxError: cannot assign to function call here. Maybe you meant '==' instead of '='?
 
     Missing ':' before suites:
 
@@ -843,6 +843,26 @@
    Traceback (most recent call last):
    SyntaxError: expected ':'
 
+   >>> if x = 3:
+   ...    pass
+   Traceback (most recent call last):
+   SyntaxError: invalid syntax. Maybe you meant '==' or ':=' instead of '='?
+
+   >>> while x = 3:
+   ...    pass
+   Traceback (most recent call last):
+   SyntaxError: invalid syntax. Maybe you meant '==' or ':=' instead of '='?
+
+   >>> if x.a = 3:
+   ...    pass
+   Traceback (most recent call last):
+   SyntaxError: cannot assign to attribute here. Maybe you meant '==' instead of '='?
+
+   >>> while x.a = 3:
+   ...    pass
+   Traceback (most recent call last):
+   SyntaxError: cannot assign to attribute here. Maybe you meant '==' instead of '='?
+
 Make sure that the old "raise X, Y[, Z]" form is gone:
    >>> raise X, Y
    Traceback (most recent call last):
@@ -894,19 +914,19 @@
 
 >>> {1, 2, 3} = 42
 Traceback (most recent call last):
-SyntaxError: cannot assign to set display. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to set display here. Maybe you meant '==' instead of '='?
 
 >>> {1: 2, 3: 4} = 42
 Traceback (most recent call last):
-SyntaxError: cannot assign to dict display. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to dict literal here. Maybe you meant '==' instead of '='?
 
 >>> f'{x}' = 42
 Traceback (most recent call last):
-SyntaxError: cannot assign to f-string expression. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to f-string expression here. Maybe you meant '==' instead of '='?
 
 >>> f'{x}-{y}' = 42
 Traceback (most recent call last):
-SyntaxError: cannot assign to f-string expression. Maybe you meant '==' instead of '='?
+SyntaxError: cannot assign to f-string expression here. Maybe you meant '==' instead of '='?
 
 >>> from t import x,
 Traceback (most recent call last):
@@ -988,7 +1008,7 @@ def _check_error(self, code, errtext,
     def test_expression_with_assignment(self):
         self._check_error(
             "print(end1 + end2 = ' ')",
-            "cannot assign to expression. Maybe you meant '==' instead of '='?",
+            "cannot assign to expression here. Maybe you meant '==' instead of '='?",
             offset=19
         )
 

Parser/parser.c

@@ -17262,7 +17262,7 @@ invalid_kwarg_rule(Parser *p)
 // invalid_named_expression:
 //     | expression ':=' expression
 //     | NAME '=' bitwise_or !('=' | ':=' | ',')
-//     | !(list | tuple) bitwise_or '=' bitwise_or !('=' | ':=' | ',')
+//     | !(list | tuple | genexp | 'True' | 'None' | 'False') bitwise_or '=' bitwise_or !('=' | ':=' | ',')
 static void *
 invalid_named_expression_rule(Parser *p)
 {
@@ -17335,12 +17335,12 @@ invalid_named_expression_rule(Parser *p)
         D(fprintf(stderr, "%*c%s invalid_named_expression[%d-%d]: %s failed!\n", p->level, ' ',
                   p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "NAME '=' bitwise_or !('=' | ':=' | ',')"));
     }
-    { // !(list | tuple) bitwise_or '=' bitwise_or !('=' | ':=' | ',')
+    { // !(list | tuple | genexp | 'True' | 'None' | 'False') bitwise_or '=' bitwise_or !('=' | ':=' | ',')
         if (p->error_indicator) {
             D(p->level--);
             return NULL;
         }
-        D(fprintf(stderr, "%*c> invalid_named_expression[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "!(list | tuple) bitwise_or '=' bitwise_or !('=' | ':=' | ',')"));
+        D(fprintf(stderr, "%*c> invalid_named_expression[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "!(list | tuple | genexp | 'True' | 'None' | 'False') bitwise_or '=' bitwise_or !('=' | ':=' | ',')"));
         expr_ty a;
         Token * b;
         expr_ty bitwise_or_var;
@@ -17356,8 +17356,8 @@ invalid_named_expression_rule(Parser *p)
             _PyPegen_lookahead(0, _tmp_145_rule, p)
         )
         {
-            D(fprintf(stderr, "%*c+ invalid_named_expression[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "!(list | tuple) bitwise_or '=' bitwise_or !('=' | ':=' | ',')"));
-            _res = RAISE_SYNTAX_ERROR_KNOWN_LOCATION ( b , "cannot assign to %s. Maybe you meant '==' instead of '='?" , _PyPegen_get_expr_name ( a ) );
+            D(fprintf(stderr, "%*c+ invalid_named_expression[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "!(list | tuple | genexp | 'True' | 'None' | 'False') bitwise_or '=' bitwise_or !('=' | ':=' | ',')"));
+            _res = RAISE_SYNTAX_ERROR_KNOWN_LOCATION ( b , "cannot assign to %s here. Maybe you meant '==' instead of '='?" , _PyPegen_get_expr_name ( a ) );
             if (_res == NULL && PyErr_Occurred()) {
                 p->error_indicator = 1;
                 D(p->level--);
@@ -17367,7 +17367,7 @@ invalid_named_expression_rule(Parser *p)
         }
         p->mark = _mark;
         D(fprintf(stderr, "%*c%s invalid_named_expression[%d-%d]: %s failed!\n", p->level, ' ',
-                  p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "!(list | tuple) bitwise_or '=' bitwise_or !('=' | ':=' | ',')"));
+                  p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "!(list | tuple | genexp | 'True' | 'None' | 'False') bitwise_or '=' bitwise_or !('=' | ':=' | ',')"));
     }
     _res = NULL;
   done:
@@ -27615,7 +27615,7 @@ _tmp_143_rule(Parser *p)
     return _res;
 }
 
-// _tmp_144: list | tuple
+// _tmp_144: list | tuple | genexp | 'True' | 'None' | 'False'
 static void *
 _tmp_144_rule(Parser *p)
 {
@@ -27664,6 +27664,82 @@ _tmp_144_rule(Parser *p)
         D(fprintf(stderr, "%*c%s _tmp_144[%d-%d]: %s failed!\n", p->level, ' ',
                   p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "tuple"));
     }
+    { // genexp
+        if (p->error_indicator) {
+            D(p->level--);
+            return NULL;
+        }
+        D(fprintf(stderr, "%*c> _tmp_144[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "genexp"));
+        expr_ty genexp_var;
+        if (
+            (genexp_var = genexp_rule(p))  // genexp
+        )
+        {
+            D(fprintf(stderr, "%*c+ _tmp_144[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "genexp"));
+            _res = genexp_var;
+            goto done;
+        }
+        p->mark = _mark;
+        D(fprintf(stderr, "%*c%s _tmp_144[%d-%d]: %s failed!\n", p->level, ' ',
+                  p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "genexp"));
+    }
+    { // 'True'
+        if (p->error_indicator) {
+            D(p->level--);
+            return NULL;
+        }
+        D(fprintf(stderr, "%*c> _tmp_144[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "'True'"));
+        Token * _keyword;
+        if (
+            (_keyword = _PyPegen_expect_token(p, 524))  // token='True'
+        )
+        {
+            D(fprintf(stderr, "%*c+ _tmp_144[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "'True'"));
+            _res = _keyword;
+            goto done;
+        }
+        p->mark = _mark;
+        D(fprintf(stderr, "%*c%s _tmp_144[%d-%d]: %s failed!\n", p->level, ' ',
+                  p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "'True'"));
+    }
+    { // 'None'
+        if (p->error_indicator) {
+            D(p->level--);
+            return NULL;
+        }
+        D(fprintf(stderr, "%*c> _tmp_144[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "'None'"));
+        Token * _keyword;
+        if (
+            (_keyword = _PyPegen_expect_token(p, 523))  // token='None'
+        )
+        {
+            D(fprintf(stderr, "%*c+ _tmp_144[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "'None'"));
+            _res = _keyword;
+            goto done;
+        }
+        p->mark = _mark;
+        D(fprintf(stderr, "%*c%s _tmp_144[%d-%d]: %s failed!\n", p->level, ' ',
+                  p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "'None'"));
+    }
+    { // 'False'
+        if (p->error_indicator) {
+            D(p->level--);
+            return NULL;
+        }
+        D(fprintf(stderr, "%*c> _tmp_144[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "'False'"));
+        Token * _keyword;
+        if (
+            (_keyword = _PyPegen_expect_token(p, 525))  // token='False'
+        )
+        {
+            D(fprintf(stderr, "%*c+ _tmp_144[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "'False'"));
+            _res = _keyword;
+            goto done;
+        }
+        p->mark = _mark;
+        D(fprintf(stderr, "%*c%s _tmp_144[%d-%d]: %s failed!\n", p->level, ' ',
+                  p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "'False'"));
+    }
     _res = NULL;
   done:
     D(p->level--);

Parser/pegen.c

@@ -199,7 +199,7 @@ _PyPegen_get_expr_name(expr_ty e)
         case DictComp_kind:
             return "dict comprehension";
         case Dict_kind:
-            return "dict display";
+            return "dict literal";
         case Set_kind:
             return "set display";
         case JoinedStr_kind: