Fix parsing of bracketed then called context managers (GH-5404)

Require the bracketed multiple context managers to be followed by a
colon, so that the bracketed called context manager is identified as
regular parentheses in old-style syntax.

Fixes https://github.com/cython/cython/issues/5403

1 files changed, 4 insertions, 0 deletions

diff --git a/Cython/Compiler/Parsing.py b/Cython/Compiler/Parsing.py
index 7c7b7f8a8..a796c865a 100644
--- a/Cython/Compiler/Parsing.py
+++ b/Cython/Compiler/Parsing.py
@@ -2141,6 +2141,10 @@ def p_with_items(s, is_async=False):
             s.next()
             items = p_with_items_list(s, is_async)
             s.expect(")")
+            if s.sy != ":":
+                # Fail - the message doesn't matter because we'll try the
+                # non-bracket version so it'll never be shown
+                s.error("")
         brackets_succeeded = not errors
     if not brackets_succeeded:
         # try the non-bracket version