private static ConditionalExpressionSyntax InvertConditionalExpression(
ConditionalExpressionSyntax conditionalExpression,
SemanticModel semanticModel,
CancellationToken cancellationToken)
{
ExpressionSyntax whenTrue = conditionalExpression.WhenTrue;
ExpressionSyntax whenFalse = conditionalExpression.WhenFalse;
if (whenTrue?.IsKind(SyntaxKind.ThrowExpression) == false)
{
whenTrue = LogicallyNegateAndParenthesize(whenTrue, semanticModel, cancellationToken);
}
if (whenFalse?.IsKind(SyntaxKind.ThrowExpression) == false)
{
whenFalse = LogicallyNegateAndParenthesize(whenFalse, semanticModel, cancellationToken);
}
ConditionalExpressionSyntax newConditionalExpression = conditionalExpression.Update(
conditionalExpression.Condition,
conditionalExpression.QuestionToken,
whenTrue,
conditionalExpression.ColonToken,
whenFalse);
return(newConditionalExpression.WithTriviaFrom(conditionalExpression));
}
private static ExpressionSyntax NegateConditionalExpression(ConditionalExpressionSyntax conditionalExpression)
{
ExpressionSyntax whenTrue = conditionalExpression.WhenTrue;
ExpressionSyntax whenFalse = conditionalExpression.WhenFalse;
if (whenTrue?.IsKind(SyntaxKind.ThrowExpression) == false)
{
whenTrue = whenTrue
.LogicallyNegate()
.ParenthesizeIfNecessary(SyntaxKind.ConditionalExpression)
.WithTriviaFrom(whenTrue);
}
if (whenFalse?.IsKind(SyntaxKind.ThrowExpression) == false)
{
whenFalse = whenFalse
.LogicallyNegate()
.ParenthesizeIfNecessary(SyntaxKind.ConditionalExpression)
.WithTriviaFrom(whenFalse);
}
ConditionalExpressionSyntax newConditionalExpression = conditionalExpression.Update(
conditionalExpression.Condition,
conditionalExpression.QuestionToken,
whenTrue,
conditionalExpression.ColonToken,
whenFalse);
return(newConditionalExpression.WithTriviaFrom(conditionalExpression));
}
public static Task <Document> RefactorAsync(
Document document,
BinaryExpressionSyntax binaryExpression,
CancellationToken cancellationToken = default)
{
ExpressionSyntax left = binaryExpression.Left.WithoutTrivia();
ExpressionSyntax right = binaryExpression.Right.WithoutTrivia();
ExpressionSyntax expression = left.WalkDownParentheses();
ExpressionSyntax condition;
ExpressionSyntax whenTrue;
if (expression.IsKind(SyntaxKind.AsExpression))
{
var asExpression = (BinaryExpressionSyntax)expression;
condition = IsExpression(
asExpression.Left,
Token(SyntaxKind.IsKeyword).WithTriviaFrom(asExpression.OperatorToken),
asExpression.Right);
whenTrue = CastExpression((TypeSyntax)asExpression.Right, asExpression.Left.Parenthesize());
}
else
{
condition = NotEqualsExpression(left, NullLiteralExpression());
whenTrue = left;
}
ConditionalExpressionSyntax conditionalExpression = ConditionalExpression(
condition.ParenthesizeIf(!CSharpFacts.IsSingleTokenExpression(condition.Kind()), simplifiable: false),
whenTrue.Parenthesize(),
right.Parenthesize());
conditionalExpression = conditionalExpression
.WithTriviaFrom(binaryExpression)
.WithFormatterAnnotation();
return(document.ReplaceNodeAsync(binaryExpression, conditionalExpression, cancellationToken));
}