This bug report has been added as Serihy asked me to:

Please open a new issue for IDLE. Perhaps there is already an open issue for SyntaxWarning in IDLE.

The main problem is that as Pablo said:

Unless I am missing something it should be 3.11 non-silent warning and 3.12 syntax error

However, on a Windows 11 device, the IDLE version of Python 3.11 still does not raise a non-silent warning.
When I tried this out:

>>> [0x1for i in range(10)]
[31]

it does not raise the warning. This was run in interactive mode.
Was the bugfix implemented only for shell mode? Or is there something in the interpreter that does not raise the SyntaxWarning?

Environment

• CPython versions tested on: 3.11.0
• Operating system and architecture: Dell Inspiron 15, Windows 11, IDLE interactive