Hi Ivan! That's actually a nice idea for a detekt rule! Without the source code it's very hard to he...

# detekt

[schalkms]

Hi Ivan! That's actually a nice idea for a detekt rule! Without the source code it's very hard to help you. Can you post a link to your source code please?

[antsiferov.ivan]

Methods visitReturnExpression and visitUnaryExpression don’t work for unary expressions, whose result is not used. That expressions simply do not get visited by those methods (or I’m doing something wrong). So I tried to parse code like strings, but that is very fragile way to solve this case. I wonder, if there is a way to detect unary expressions with unused result, using methods from org.jetbrains.kotlin.psi.

[antsiferov.ivan]

Snippet with parsing code as string can be found here https://pastebin.com/3jz2J9Ps

[schalkms]

What's your test code? Can you give one example where visitUnaryExpression is not called?
You are right. You will run into false positives with your approach.

[antsiferov.ivan]

Yep, here it is https://pastebin.com/xPyXdR6L . + variableWithVeryVeryVeryVeryVeryVeryLongName is unary expression, but visitUnaryExpression did not get called for it.

[schalkms]

I took the time to try your rule locally.
Actually + variableWithVeryVeryVeryVeryVeryVeryLongName is a separate PsiElement.

[schalkms]

The type of this element is KtPrefixExpression.

[schalkms]

I used the IntelliJ debugger and went through the abstract syntax tree. With this trick you get to know the types and elements of a specific code snippet.

[schalkms]

Weirdly though, the following code snippet yields 1 for the variable x.

val x = 1
     + 2

I think there is also an issue in the repo.

[antsiferov.ivan]

Thnx for trying to figure out how to solve this issue.
x has value of 1, because “+2” is separate expression, and its result is not used. If plus was in the end of line:

val x = 1 +
        2

It will behave as expected.