bpo-30858: Improve error location for expressions with assignments (GH-23753)

Co-authored-by: Lysandros Nikolaou <lisandrosnik@gmail.com>
diff --git a/Lib/test/test_exceptions.py b/Lib/test/test_exceptions.py
index 1bdd3f2..e752ab7 100644
--- a/Lib/test/test_exceptions.py
+++ b/Lib/test/test_exceptions.py
@@ -252,7 +252,7 @@ def baz():
         check('from __future__ import doesnt_exist', 1, 1)
         check('from __future__ import braces', 1, 1)
         check('x=1\nfrom __future__ import division', 2, 1)
-        check('foo(1=2)', 1, 5)
+        check('foo(1=2)', 1, 6)
         check('def f():\n  x, y: int', 2, 3)
         check('[*x for x in xs]', 1, 2)
         check('foo(x for x in range(10), 100)', 1, 5)