protected override void AnalyzeNode(SyntaxNodeAnalysisContext context, EnabledRules rules)
{
var node = context.Node;
var semanticModel = context.SemanticModel;
Action <Diagnostic> reportDiagnostic = context.ReportDiagnostic;
var cancellationToken = context.CancellationToken;
string filePath = node.SyntaxTree.FilePath;
var invocationExpression = node as InvocationExpressionSyntax;
if (semanticModel.GetSymbolInfo(invocationExpression, cancellationToken).Symbol is IMethodSymbol methodInfo)
{
if (rules.IsEnabled(AllocationRules.ValueTypeNonOverridenCallRule.Id))
{
if (methodInfo.IsOverride)
{
var rule = rules.Get(AllocationRules.ValueTypeNonOverridenCallRule.Id);
CheckNonOverridenMethodOnStruct(rule, methodInfo, reportDiagnostic, invocationExpression, filePath);
}
}
if (rules.IsEnabled(AllocationRules.ParamsParameterRule.Id))
{
if (methodInfo.Parameters.Length > 0 && invocationExpression.ArgumentList != null)
{
var lastParam = methodInfo.Parameters[methodInfo.Parameters.Length - 1];
if (lastParam.IsParams)
{
var rule = rules.Get(AllocationRules.ParamsParameterRule.Id);
CheckParam(rule, invocationExpression, methodInfo, semanticModel, reportDiagnostic, filePath, cancellationToken);
}
}
}
}
}
private static void ArrowExpressionCheck(EnabledRules rules, SyntaxNode node, SemanticModel semanticModel, bool isAssignmentToReadonly, Action <Diagnostic> reportDiagnostic, string filePath, CancellationToken cancellationToken)
{
var syntax = node as ArrowExpressionClauseSyntax;
var typeInfo = semanticModel.GetTypeInfo(syntax.Expression, cancellationToken);
var conversionInfo = semanticModel.GetConversion(syntax.Expression, cancellationToken);
CheckTypeConversion(rules.Get(AllocationRules.ValueTypeToReferenceTypeConversionRule.Id), conversionInfo, reportDiagnostic, syntax.Expression.GetLocation(), filePath);
CheckDelegateCreation(rules, syntax, typeInfo, semanticModel, false, reportDiagnostic,
syntax.Expression.GetLocation(), filePath, cancellationToken);
}
private static void EqualsValueClauseCheck(EnabledRules rules, SyntaxNode node, SemanticModel semanticModel, bool isAssignmentToReadonly, Action <Diagnostic> reportDiagnostic, string filePath, CancellationToken cancellationToken)
{
var initializer = node as EqualsValueClauseSyntax;
if (initializer.Value != null)
{
var typeInfo = semanticModel.GetTypeInfo(initializer.Value, cancellationToken);
var conversionInfo = semanticModel.GetConversion(initializer.Value, cancellationToken);
CheckTypeConversion(rules.Get(AllocationRules.ValueTypeToReferenceTypeConversionRule.Id), conversionInfo, reportDiagnostic, initializer.Value.GetLocation(), filePath);
CheckDelegateCreation(rules, initializer.Value, typeInfo, semanticModel, isAssignmentToReadonly, reportDiagnostic, initializer.Value.GetLocation(), filePath, cancellationToken);
}
}
protected override void AnalyzeNode(SyntaxNodeAnalysisContext context, EnabledRules rules)
{
var node = context.Node;
var semanticModel = context.SemanticModel;
Action <Diagnostic> reportDiagnostic = context.ReportDiagnostic;
var cancellationToken = context.CancellationToken;
string filePath = node.SyntaxTree.FilePath;
var binaryExpressions = node.DescendantNodesAndSelf().OfType <BinaryExpressionSyntax>().Reverse(); // need inner most expressions
int stringConcatenationCount = 0;
foreach (var binaryExpression in binaryExpressions)
{
if (binaryExpression.Left == null || binaryExpression.Right == null)
{
continue;
}
bool isConstant = semanticModel.GetConstantValue(binaryExpression, cancellationToken).HasValue;
if (isConstant)
{
continue;
}
// TODO: TryGetEnabled()
var left = semanticModel.GetTypeInfo(binaryExpression.Left, cancellationToken);
var right = semanticModel.GetTypeInfo(binaryExpression.Right, cancellationToken);
if (rules.TryGet(AllocationRules.ValueTypeToReferenceTypeInAStringConcatenationRule.Id, out var rule))
{
var leftConversion = semanticModel.GetConversion(binaryExpression.Left, cancellationToken);
var rightConversion = semanticModel.GetConversion(binaryExpression.Right, cancellationToken);
CheckTypeConversion(rule, left, leftConversion, reportDiagnostic, binaryExpression.Left.GetLocation(), filePath);
CheckTypeConversion(rule, right, rightConversion, reportDiagnostic, binaryExpression.Right.GetLocation(), filePath);
}
// regular string allocation
if (rules.IsEnabled(AllocationRules.StringConcatenationAllocationRule.Id))
{
if (left.Type?.SpecialType == SpecialType.System_String || right.Type?.SpecialType == SpecialType.System_String)
{
stringConcatenationCount++;
}
}
}
if (stringConcatenationCount > 3)
{
var rule = rules.Get(AllocationRules.StringConcatenationAllocationRule.Id);
reportDiagnostic(Diagnostic.Create(rule, node.GetLocation(), EmptyMessageArgs));
}
}
private static void ArgumentSyntaxCheck(EnabledRules rules, SyntaxNode node, SemanticModel semanticModel, bool isAssignmentToReadonly, Action <Diagnostic> reportDiagnostic, string filePath, CancellationToken cancellationToken)
{
var argument = node as ArgumentSyntax;
if (argument.Expression != null)
{
if (rules.IsEnabled(AllocationRules.ValueTypeToReferenceTypeConversionRule.Id))
{
var argumentTypeInfo = semanticModel.GetTypeInfo(argument.Expression, cancellationToken);
var argumentConversionInfo = semanticModel.GetConversion(argument.Expression, cancellationToken);
CheckTypeConversion(rules.Get(AllocationRules.ValueTypeToReferenceTypeConversionRule.Id), argumentConversionInfo, reportDiagnostic, argument.Expression.GetLocation(), filePath);
CheckDelegateCreation(rules, argument.Expression, argumentTypeInfo, semanticModel, isAssignmentToReadonly, reportDiagnostic, argument.Expression.GetLocation(), filePath, cancellationToken);
}
}
}
private static void CheckDelegateCreation(EnabledRules rules, SyntaxNode node, TypeInfo typeInfo, SemanticModel semanticModel, bool isAssignmentToReadonly, Action <Diagnostic> reportDiagnostic, Location location, string filePath, CancellationToken cancellationToken)
{
if (typeInfo.ConvertedType?.TypeKind != TypeKind.Delegate)
{
return;
}
if (rules.TryGet(AllocationRules.DelegateOnStructInstanceRule.Id, out var delegateOnStructRule))
{
var symbolInfo = semanticModel.GetSymbolInfo(node, cancellationToken).Symbol;
if (symbolInfo?.ContainingType?.IsValueType == true && symbolInfo.GetType().Name == "SourceMemberMethodSymbol")
{
reportDiagnostic(Diagnostic.Create(delegateOnStructRule, location, EmptyMessageArgs));
}
}
// new Action<Foo>(MethodGroup); should skip this one
var insideObjectCreation = node?.Parent?.Parent?.Parent?.Kind() == SyntaxKind.ObjectCreationExpression;
if (node is ParenthesizedLambdaExpressionSyntax || node is SimpleLambdaExpressionSyntax ||
node is AnonymousMethodExpressionSyntax || node is ObjectCreationExpressionSyntax ||
insideObjectCreation)
{
// skip this, because it's intended.
return;
}
if (rules.IsEnabled(AllocationRules.MethodGroupAllocationRule.Id) && node.IsKind(SyntaxKind.IdentifierName))
{
if (semanticModel.GetSymbolInfo(node, cancellationToken).Symbol is IMethodSymbol)
{
reportDiagnostic(Diagnostic.Create(rules.Get(AllocationRules.MethodGroupAllocationRule.Id), location, EmptyMessageArgs));
}
}
else if (node.IsKind(SyntaxKind.SimpleMemberAccessExpression))
{
var memberAccess = node as MemberAccessExpressionSyntax;
if (semanticModel.GetSymbolInfo(memberAccess.Name, cancellationToken).Symbol is IMethodSymbol)
{
if (isAssignmentToReadonly && rules.TryGet(AllocationRules.ReadonlyMethodGroupAllocationRule.Id, out var readonlyMethodGroupAllocationRule))
{
reportDiagnostic(Diagnostic.Create(readonlyMethodGroupAllocationRule, location, EmptyMessageArgs));
}
else if (rules.TryGet(AllocationRules.MethodGroupAllocationRule.Id, out var methodGroupAllocationRule))
{
reportDiagnostic(Diagnostic.Create(methodGroupAllocationRule, location, EmptyMessageArgs));
}
}
}
else if (node is ArrowExpressionClauseSyntax)
{
if (rules.TryGet(AllocationRules.MethodGroupAllocationRule.Id, out var methodGroupAllocationRule))
{
var arrowClause = node as ArrowExpressionClauseSyntax;
if (semanticModel.GetSymbolInfo(arrowClause.Expression, cancellationToken).Symbol is IMethodSymbol)
{
reportDiagnostic(Diagnostic.Create(methodGroupAllocationRule, location, EmptyMessageArgs));
}
}
}
}