Indicate whether a proposed fix is unsafe

[ThiefMaster]

For example, this one would break the code (because is not cannot be overridden, so for certain SQLAlchemy comparisions, ==/!= comparisons against None are required):

Of course I know that it would not be safe to "fix" it, but maybe a less experienced developer might blindly apply the fix instead of adding noqa and then wonder why their code does not work.

[zanieb]

I'm not sure how best to display this information. I worry that just appending "(unsafe)" would be confusing.

[ThiefMaster]

⚠️ icon maybe?

[zanieb]

I think in the long-run we'd want the ability to show why a fix is unsafe as well otherwise it doesn't seem helpful to the naive user.