private async static Task <Document> UseVarAsync(Document document, Diagnostic diagnostic, CancellationToken cancellationToken)
        {
            var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);

            var diagnosticSpan      = diagnostic.Location.SourceSpan;
            var localDeclaration    = root.FindToken(diagnosticSpan.Start).Parent.AncestorsAndSelf().OfType <LocalDeclarationStatementSyntax>().First();
            var variableDeclaration = localDeclaration.Declaration;
            var numVariables        = variableDeclaration.Variables.Count;

            var newVariableDeclarations = new VariableDeclarationSyntax[numVariables];

            var varSyntax = SyntaxFactory.IdentifierName("var");

            //Create a new var declaration for each variable.
            for (var i = 0; i < numVariables; i++)
            {
                var originalVariable = variableDeclaration.Variables[i];
                var newLeadingTrivia = originalVariable.GetLeadingTrivia();

                //Get the trivia from the separator as well
                if (i != 0)
                {
                    newLeadingTrivia = newLeadingTrivia.InsertRange(0,
                                                                    variableDeclaration.Variables.GetSeparator(i - 1).GetAllTrivia());
                }

                newVariableDeclarations[i] = SyntaxFactory.VariableDeclaration(varSyntax)
                                             .AddVariables(originalVariable.WithLeadingTrivia(newLeadingTrivia));
            }

            //ensure trivia for leading type node is preserved
            var originalTypeSyntax = variableDeclaration.Type;

            newVariableDeclarations[0] = newVariableDeclarations[0]
                                         .WithType((TypeSyntax)varSyntax.WithSameTriviaAs(originalTypeSyntax));

            var newLocalDeclarationStatements = newVariableDeclarations.Select(SyntaxFactory.LocalDeclarationStatement).ToList();


            //Preserve the trivia for the entire statement at the start and at the end
            newLocalDeclarationStatements[0] =
                newLocalDeclarationStatements[0].WithLeadingTrivia(variableDeclaration.GetLeadingTrivia());
            var lastIndex = numVariables - 1;

            newLocalDeclarationStatements[lastIndex] =
                newLocalDeclarationStatements[lastIndex].WithTrailingTrivia(localDeclaration.GetTrailingTrivia());

            var newRoot     = root.ReplaceNode(localDeclaration, newLocalDeclarationStatements);
            var newDocument = document.WithSyntaxRoot(newRoot);

            return(newDocument);
        }