Fix S1450 FP: private field is used in several methods

[nalka0]

Description

S1450 is raised on the following snippet despite foundMultiple being used on both methods

Repro steps

private class LookForSinglePropertyAccessExpressionVisitor : ExpressionVisitor
{
    private PropertyInfo foundProperty;

    private bool foundMultiple; // S1450 FP here (but it's used on both methods)

    public PropertyInfo GetUsedProperty(Expression expression)
    {
        foundProperty = null;
        foundMultiple = false;
        Visit(expression);
        if (foundMultiple)
        {
            throw new ArgumentException($"{expression} contains more than one property access", nameof(expression));
        }

        return foundProperty ?? throw new ArgumentException($"{expression} contains no property access", nameof(expression));
    }

    protected override Expression VisitMember(MemberExpression node)
    {
        if (node.Member is PropertyInfo prop)
        {
            if (foundProperty != null)
            {
                foundMultiple = true;
            }

            foundProperty = prop;
        }

        return base.VisitMember(node);
    }
}

Expected behavior

No occurrence of S1450 in the above snippet

Actual behavior

S1450 is raised on the above snippet despite foundMultiple being used on both methods

Known workarounds

None

Related information

• Microsoft Visual Studio Community 2022 - Version 17.11.4
• .NET 6 and 8
• SonarScanner for .NET version 9.0.0
• Windows 11

[CristianAmbrosini]

Hi @nalka0!

It's a FP, indeed.
I discovered that we already have a reproducer for this on our repo.
I'll make sure to add a link to this since it seems we don't have a ticket for it yet.

Thanks,