bpo-44456: Improve the syntax error when mixing keyword and positional patterns (GH-26793)

(cherry picked from commit 0acc258fe6f0ec200ca2f6f9294adbf52a244802)

Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py
index e0d0445a83..ad5656bac6 100644
--- a/Lib/test/test_syntax.py
+++ b/Lib/test/test_syntax.py
@@ -1240,6 +1240,30 @@ Corner-cases that used to crash:
     ...     ...
     Traceback (most recent call last):
     SyntaxError: invalid pattern target
+
+    >>> match ...:
+    ...   case Foo(z=1, y=2, x):
+    ...     ...
+    Traceback (most recent call last):
+    SyntaxError: positional patterns follow keyword patterns
+
+    >>> match ...:
+    ...   case Foo(a, z=1, y=2, x):
+    ...     ...
+    Traceback (most recent call last):
+    SyntaxError: positional patterns follow keyword patterns
+
+    >>> match ...:
+    ...   case Foo(z=1, x, y=2):
+    ...     ...
+    Traceback (most recent call last):
+    SyntaxError: positional patterns follow keyword patterns
+
+    >>> match ...:
+    ...   case C(a=b, c, d=e, f, g=h, i, j=k, ...):
+    ...     ...
+    Traceback (most recent call last):
+    SyntaxError: positional patterns follow keyword patterns
 """
 
 import re