I too analyzed the code and yes, changing it to null won't have any effect because:

1. DetailAST typeAst is only used while logging violations, and we only log violations for local variables, and this VariableDesc is for an instance or class variable.
2. DetailAST scope. We never use the initially set scope. When we use scope, we update it to our value before using it. See

   checkstyle/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/UnusedLocalVariableCheck.java

   Lines 1010 to 1020 in 3f77dd1

   	public Deque<VariableDesc> getUpdatedCopyOfVarStack(DetailAST literalNewAst) {
   	final DetailAST updatedScope = literalNewAst.getLastChild();
   	final Deque<VariableDesc> instAndClassVarDeque = new ArrayDeque<>();
   	instanceAndClassVarStack.forEach(instVar -> {
   	final VariableDesc variableDesc = new VariableDesc(instVar.getName(),
   	instVar.getTypeAst(), updatedScope);
   	variableDesc.registerAsInstOrClassVar();
   	instAndClassVarDeque.push(variableDesc);
   	});
   	return instAndClassVarDeque;
   	}

   we use updatedScope instead.

So all in all, we can safely do these changes BUT this is not a good design. The design of the check should be altered to not have situations like these. This is out of the scope of this summer's project, a separate issue to enhance the design of the check should be created.

LGTM!

Ok, I don't have time now to investigate in detail.

We will deal with this in separate project

Considering VariableDesc is a nested private class, can we introduce another constructor VariableDesc(String name) and remove those null arguments?

@rdiachenko done
There is no such solution for new surviving mutation.
hcoles/pitest#1230

@Kevin222004 you can reuse another constructor to set values, please update it to the following:

private VariableDesc(String name) {
    this(name, null, null);
}

done

Why not ?

private VariableDesc(String name) {
            this.name = name;
        }

And it will avoid Checker problems mostlikely

@romani @rdiachenko ping

I don't see reply to #13145 (comment)

If code is by design, we should just explain Checker that fields are nullable.

@romani I have tried what you say it leads to other new suppression and after solving it it leads to some other suppression I request you to not cover this here please if you want to check I can update the pr.
If you want to complete it allow me to create a new pr and complete it please do not cover this pr.

@romani ping

@romani ping