[Python-checkins] bpo-39176: Improve error message for 'named assignment' (GH-17777) (GH-17778)

[Raymond Hettinger]

https://github.com/python/cpython/commit/6c004955aceb8a0cd8e14afbc608ebfdf7c8aa4a
commit: 6c004955aceb8a0cd8e14afbc608ebfdf7c8aa4a
branch: 3.8
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: Raymond Hettinger <rhettinger at users.noreply.github.com>
date: 2019-12-31T21:28:08-06:00
summary:

bpo-39176: Improve error message for 'named assignment' (GH-17777) (GH-17778)

(cherry picked from commit 37143a8e3b2e9245d52f4ddebbdd1c6121c96884)

Co-authored-by: Ned Batchelder <ned at nedbatchelder.com>

Co-authored-by: Ned Batchelder <ned at nedbatchelder.com>

files:
M Lib/test/test_named_expressions.py
M Lib/test/test_syntax.py
M Python/ast.c

diff --git a/Lib/test/test_named_expressions.py b/Lib/test/test_named_expressions.py
index 01e26c8dfaf25..3ae557f78d273 100644
--- a/Lib/test/test_named_expressions.py
+++ b/Lib/test/test_named_expressions.py
@@ -32,7 +32,7 @@ def test_named_expression_invalid_04(self):
     def test_named_expression_invalid_06(self):
         code = """((a, b) := (1, 2))"""
 
-        with self.assertRaisesRegex(SyntaxError, "cannot use named assignment with tuple"):
+        with self.assertRaisesRegex(SyntaxError, "cannot use assignment expressions with tuple"):
             exec(code, {}, {})
 
     def test_named_expression_invalid_07(self):
@@ -90,7 +90,7 @@ def test_named_expression_invalid_15(self):
         code = """(lambda: x := 1)"""
 
         with self.assertRaisesRegex(SyntaxError,
-            "cannot use named assignment with lambda"):
+            "cannot use assignment expressions with lambda"):
             exec(code, {}, {})
 
     def test_named_expression_invalid_16(self):
diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py
index 3829746f1799a..128c4da143841 100644
--- a/Lib/test/test_syntax.py
+++ b/Lib/test/test_syntax.py
@@ -45,7 +45,7 @@
 
 >>> (True := 1)
 Traceback (most recent call last):
-SyntaxError: cannot use named assignment with True
+SyntaxError: cannot use assignment expressions with True
 
 >>> obj.__debug__ = 1
 Traceback (most recent call last):
diff --git a/Python/ast.c b/Python/ast.c
index e70ab519e66e1..6cf71ce7bb810 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1955,7 +1955,7 @@ ast_for_namedexpr(struct compiling *c, const node *n)
     if (target->kind != Name_kind) {
         const char *expr_name = get_expr_name(target);
         if (expr_name != NULL) {
-            ast_error(c, n, "cannot use named assignment with %s", expr_name);
+            ast_error(c, n, "cannot use assignment expressions with %s", expr_name);
         }
         return NULL;
     }