`unnecessary_cfg_test`

What it does

Since #[test] is already implicitly #[cfg(test)], it would not be needed to use #[cfg(test)] directly on a function.

I propose this lint to catch cases of

#[cfg(test)]
#[test]
fn test() {}

Suggesting instead to either remove the cfg (for inline tests), to add it to the module itself (for inline modules, e.g. #[cfg(test)] mod test {}) or to use #![cfg(test)] at the head of the file (for test files).

Lint Name

unnecessary_cfg_test

Category

style

Advantage

Removes redundant code

Drawbacks

None that I'm aware of

Example

#[cfg(test)]
#[test]
fn test() {}

Could be written as:

// test file
#![cfg(test)]

#[test]
fn test() {}

// inline test
#[test]
fn test() {}

// inline test module
#[cfg(test)] 
mod test {
    #[test]
    fn test() {}
}

The issue does not name implementation files or tests; start by reading its examples and the referenced Cargo issue to understand the proposed cases. Done means adding the unnecessary_cfg_test lint and ensuring it handles inline tests, inline test modules, and test files as described.