private static bool HaveSameTarget([NotNull] IOperation leftOperation, [NotNull] IOperation rightOperation,
[NotNull] NullCheckScanner scanner)
{
IOperation innerRightOperation = SkipNullableValueProperty(rightOperation, scanner.NullableHasValueProperty);
return(OperationEqualityComparer.Default.Equals(leftOperation, innerRightOperation));
}
private void AnalyzeBinaryOperator(OperationAnalysisContext context, [NotNull] NullCheckScanner scanner)
{
var binaryOperator = (IBinaryOperation)context.Operation;
NullCheckScanResult?scanResult = scanner.ScanBinaryOperator(binaryOperator);
ReportForScanResult(scanResult, context.ReportDiagnostic);
}
private void AnalyzeIsPattern(OperationAnalysisContext context, [NotNull] NullCheckScanner scanner)
{
var isPattern = (IIsPatternOperation)context.Operation;
NullCheckScanResult?scanResult = scanner.ScanIsPattern(isPattern);
ReportForScanResult(scanResult, context.ReportDiagnostic);
}
private void AnalyzePropertyReference(OperationAnalysisContext context, [NotNull] NullCheckScanner scanner)
{
var propertyReference = (IPropertyReferenceOperation)context.Operation;
NullCheckScanResult?scanResult = scanner.ScanPropertyReference(propertyReference);
ReportForScanResult(scanResult, context.ReportDiagnostic);
}
private static void AnalyzeBinaryOperator(OperationAnalysisContext context, [NotNull] NullCheckScanner scanner)
{
var binaryOperator = (IBinaryOperation)context.Operation;
if (DoReportForNullableComparison(binaryOperator, scanner))
{
context.ReportDiagnostic(Diagnostic.Create(NullableComparisonRule, binaryOperator.Syntax.GetLocation()));
}
}
private static void RegisterCompilationStart([NotNull] CompilationStartAnalysisContext startContext)
{
var scanner = new NullCheckScanner(startContext.Compilation);
startContext.RegisterOperationAction(context => AnalyzePropertyReferenceAction(context, scanner),
OperationKind.PropertyReference);
startContext.RegisterOperationAction(context => AnalyzeBinaryOperatorAction(context, scanner),
OperationKind.BinaryOperator);
}
public override void Initialize([NotNull] AnalysisContext context)
{
context.EnableConcurrentExecution();
context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
context.RegisterCompilationStartAction(startContext =>
{
var scanner = new NullCheckScanner(startContext.Compilation);
RegisterForOperations(startContext, scanner);
});
}
private void RegisterForOperations([NotNull] CompilationStartAnalysisContext startContext,
[NotNull] NullCheckScanner scanner)
{
startContext.RegisterOperationAction(context => context.SkipInvalid(_ => AnalyzePropertyReference(context, scanner)),
OperationKind.PropertyReference);
startContext.RegisterOperationAction(context => context.SkipInvalid(_ => AnalyzeInvocation(context, scanner)),
OperationKind.Invocation);
startContext.RegisterOperationAction(context => context.SkipInvalid(_ => AnalyzeIsPattern(context, scanner)),
OperationKind.IsPattern);
startContext.RegisterOperationAction(context => context.SkipInvalid(_ => AnalyzeBinaryOperator(context, scanner)),
OperationKind.BinaryOperator);
}
private static bool DoReportForNullableComparison([NotNull] IBinaryOperation binaryOperator,
[NotNull] NullCheckScanner scanner)
{
if (IsLogicalAnd(binaryOperator))
{
IOperation leftTarget = TryGetTargetInNotNullCheck(binaryOperator.LeftOperand, scanner);
if (leftTarget != null && !(leftTarget is IInvocationOperation))
{
if (DoReportForMatchingRightOperandInNullableComparison(binaryOperator.RightOperand, scanner, leftTarget))
{
return(true);
}
}
}
return(false);
}
private static bool DoReportForMatchingRightOperandInNullableComparison([NotNull] IOperation rightOperand,
[NotNull] NullCheckScanner scanner, [NotNull] IOperation leftTarget)
{
if (rightOperand is IBinaryOperation rightOperation &&
NumericComparisonOperators.Contains(rightOperation.OperatorKind))
{
if (HaveSameTarget(leftTarget, rightOperation.LeftOperand, scanner) ||
HaveSameTarget(leftTarget, rightOperation.RightOperand, scanner))
{
if (!IsEqualityComparisonWithNullableType(rightOperation))
{
return(true);
}
}
}
return(false);
}
private static void AnalyzePropertyReference(OperationAnalysisContext context, [NotNull] NullCheckScanner scanner)
{
var propertyReference = (IPropertyReferenceOperation)context.Operation;
NullCheckScanResult?scanResult = scanner.ScanPropertyReference(propertyReference);
if (scanResult != null && scanResult.Value.Method == NullCheckMethod.NullableHasValueMethod)
{
if (propertyReference.Parent is IBinaryOperation binaryOperator &&
DoReportForNullableComparison(binaryOperator, scanner))
{
return;
}
context.ReportDiagnostic(Diagnostic.Create(NullableHasValueRule, propertyReference.Syntax.GetLocation()));
}
}
public NullCheckVisitor([NotNull] NullCheckScanner scanner)
{
Guard.NotNull(scanner, nameof(scanner));
this.scanner = scanner;
}
private static IOperation TryGetTargetInNotNullCheck([NotNull] IOperation operation, [NotNull] NullCheckScanner scanner)
{
IOperation targetOperation = SkipNotOperators(operation);
var visitor = new NullCheckVisitor(scanner);
visitor.Visit(targetOperation);
return(visitor.ScanResult != null && visitor.ScanResult.Value.Operand == NullCheckOperand.IsNotNull
? visitor.ScanResult.Value.Target
: null);
}
