`cfg_not_test`

[JonathanWoollett-Light]

What it does

Disallows usage of any conditional compilation that always excludes code from test builds.

Advantage

• Prevents code being excluded from tests builds. Preventing the case where a codebase appears to have 100% coverage while having untested code.
• Enforces simplicity in testing, guarding against excessive mocking anti-pattern.

Drawbacks

• May prevent rare legitimate use cases for excluding code from test runs.

Example

The following would trigger this lint:

#[cfg(not(test))]

#[cfg(all(debug_assertions, not(test)))]

#[cfg(not(any(not(debug_assertions), test)))]

[blyxyas]

I feel like the drawback is too heavy for an allow-by-default lint. What do you think about restriction?

[JonathanWoollett-Light]

@blyxyas I agree it makes sense for this to be a restriction lint.

[mrnossiom]

@rustbot claim