False positive with closures

[matteo-pupa]

In the following example containing the falsePos clousure, nilaway reports the error shown below:

func main() {
	falsePos := func() (*bool, error) {
		b := false
		if rand.Float64() < 0.5 {
			return nil, fmt.Errorf("error: %v", b)
		}
		return &b, nil
	}

	res, err := falsePos()
	if err != nil {
		fmt.Println("Error:", err)
		return
	}
	fmt.Println(*res)
}

error main.go:22:15: error: Potential nil panic detected. Observed nil flow from source to dereference point: 
	-> nilaway-issue/main.go:22:15: unassigned variable `res` dereferenced

Whereas, the same function taken out of the main, causes no error:

func falsePos() (*bool, error) {
	b := false
	if rand.Float64() < 0.5 {
		return nil, fmt.Errorf("error: %v", b)
	}
	return &b, nil
}

func main() {
	res, err := falsePos()
	if err != nil {
		fmt.Println("Error:", err)
		return
	}
	fmt.Println(*res)
}

[yuxincs]

You're right! We currently only have limited support for anonymous functions and closures (in fact they are currently hidden under a feature flag that can be enabled if you add <nilaway anonymous function enable> to the file docstring).

We are prioritizing on performance validations / polishing up those features to move them to main NilAway. I'm keeping this issue open to track the work.

Thanks for the report!