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

nedbat · rhettinger · commit 37143a8e3b2e · 2019-12-31T20:40:58.000-06:00
diff --git 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
@@ -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
@@ -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;
     }

Original file line number	Diff line number	Diff line change
`@@ -1955,7 +1955,7 @@ ast_for_namedexpr(struct compiling c, const node n)`
`1955`	`1955`	`if (target->kind != Name_kind) {`
`1956`	`1956`	`const char *expr_name = get_expr_name(target);`
`1957`	`1957`	`if (expr_name != NULL) {`
`1958`		`- ast_error(c, n, "cannot use named assignment with %s", expr_name);`
	`1958`	`+ ast_error(c, n, "cannot use assignment expressions with %s", expr_name);`
`1959`	`1959`	`}`
`1960`	`1960`	`return NULL;`
`1961`	`1961`	`}`