internal static bool TryGetReturnExpression(this BlockSyntax body, SemanticModel semanticModel, CancellationToken cancellationToken, out ExpressionSyntax returnValue)
{
return(ReturnValueWalker.TrygetSingle(body, semanticModel, cancellationToken, out returnValue));
}
private static bool CanIgnore(InvocationExpressionSyntax invocation, SemanticModel semanticModel, CancellationToken cancellationToken)
{
var method = (IMethodSymbol)semanticModel.GetSymbolSafe(invocation, cancellationToken);
if (method == null || method.ReturnsVoid)
{
return(true);
}
if (!(invocation.Parent is StatementSyntax))
{
return(true);
}
if (invocation.Parent is ExpressionStatementSyntax &&
invocation.Parent.Parent is BlockSyntax)
{
if (method == KnownSymbol.StringBuilder.Append ||
method == KnownSymbol.StringBuilder.AppendLine ||
method == KnownSymbol.StringBuilder.AppendFormat ||
method == KnownSymbol.IList.Add ||
method == KnownSymbol.IList.Remove)
{
return(true);
}
if (method.TryGetSingleDeclaration(cancellationToken, out MethodDeclarationSyntax declaration))
{
using (var pooled = ReturnValueWalker.Create(declaration, Search.Recursive, semanticModel, cancellationToken))
{
if (method.IsExtensionMethod)
{
var identifier = declaration.ParameterList.Parameters[0].Identifier;
foreach (var returnValue in pooled.Item)
{
if ((returnValue as IdentifierNameSyntax)?.Identifier.ValueText != identifier.ValueText)
{
return(false);
}
}
return(true);
}
foreach (var returnValue in pooled.Item)
{
if (!returnValue.IsKind(SyntaxKind.ThisExpression))
{
return(false);
}
}
return(true);
}
}
return(method.ReturnsVoid);
}
return(true);
}
private static bool CanIgnore(InvocationExpressionSyntax invocation, SemanticModel semanticModel, CancellationToken cancellationToken)
{
if (!(invocation.Parent is StatementSyntax))
{
return(true);
}
if (invocation.Parent is ExpressionStatementSyntax &&
invocation.Parent.Parent is BlockSyntax &&
semanticModel.GetSymbolSafe(invocation, cancellationToken) is IMethodSymbol method)
{
if (method.ReturnsVoid)
{
return(true);
}
if (ReferenceEquals(method.ContainingType, method.ReturnType))
{
if (method.ContainingType == KnownSymbol.StringBuilder)
{
return(true);
}
}
if (method == KnownSymbol.IList.Add ||
method == KnownSymbol.IList.Remove)
{
return(true);
}
if (method.TryGetSingleDeclaration(cancellationToken, out MethodDeclarationSyntax declaration))
{
using (var walker = ReturnValueWalker.Borrow(declaration, Search.Recursive, semanticModel, cancellationToken))
{
if (method.IsExtensionMethod)
{
var identifier = declaration.ParameterList.Parameters[0].Identifier;
foreach (var returnValue in walker)
{
if ((returnValue as IdentifierNameSyntax)?.Identifier.ValueText != identifier.ValueText)
{
return(false);
}
}
return(true);
}
foreach (var returnValue in walker)
{
if (!returnValue.IsKind(SyntaxKind.ThisExpression))
{
return(false);
}
}
return(true);
}
}
return(method.ReturnsVoid);
}
return(true);
}
private static void Handle(SyntaxNodeAnalysisContext context)
{
if (context.IsExcludedFromAnalysis())
{
return;
}
if (context.Node is PropertyDeclarationSyntax propertyDeclaration &&
context.ContainingSymbol is IPropertySymbol property)
{
{
if (propertyDeclaration.ExpressionBody is ArrowExpressionClauseSyntax expressionBody)
{
if (property.Type.IsReferenceType &&
expressionBody.Expression is ObjectCreationExpressionSyntax)
{
context.ReportDiagnostic(Diagnostic.Create(GU0021CalculatedPropertyAllocates.Descriptor, expressionBody.GetLocation()));
}
else if (expressionBody.Expression is MemberAccessExpressionSyntax memberAccess &&
IsRelayReturn(memberAccess, context.SemanticModel, context.CancellationToken))
{
context.ReportDiagnostic(Diagnostic.Create(GU0008AvoidRelayProperties.Descriptor, memberAccess.GetLocation()));
}
}
else if (propertyDeclaration.TryGetGetter(out var getter))
{
using (var walker = ReturnValueWalker.Borrow(getter, Search.Recursive, context.SemanticModel, context.CancellationToken))
{
if (walker.TrySingle(out var returnValue))
{
if (property.Type.IsReferenceType &&
returnValue is ObjectCreationExpressionSyntax)
{
if (getter.Contains(returnValue) &&
returnValue.FirstAncestor <ReturnStatementSyntax>() is ReturnStatementSyntax returnStatement)
{
context.ReportDiagnostic(Diagnostic.Create(GU0021CalculatedPropertyAllocates.Descriptor, returnStatement.GetLocation()));
}
else
{
context.ReportDiagnostic(Diagnostic.Create(GU0021CalculatedPropertyAllocates.Descriptor, getter.GetLocation()));
}
}
else if (returnValue is MemberAccessExpressionSyntax memberAccess &&
IsRelayReturn(memberAccess, context.SemanticModel, context.CancellationToken))
{
if (getter.Contains(returnValue) &&
returnValue.FirstAncestor <ReturnStatementSyntax>() is ReturnStatementSyntax returnStatement)
{
context.ReportDiagnostic(Diagnostic.Create(GU0008AvoidRelayProperties.Descriptor, returnStatement.GetLocation()));
}
else
{
context.ReportDiagnostic(Diagnostic.Create(GU0008AvoidRelayProperties.Descriptor, getter.GetLocation()));
}
}
}
}
}
}
}
}
private bool AddRecursiveValues(ExpressionSyntax assignedValue)
{
if (assignedValue == null ||
assignedValue.IsMissing ||
!this.checkedLocations.Add(assignedValue))
{
return(false);
}
if (assignedValue is LiteralExpressionSyntax ||
assignedValue is DefaultExpressionSyntax ||
assignedValue is TypeOfExpressionSyntax ||
assignedValue is ObjectCreationExpressionSyntax ||
assignedValue is ArrayCreationExpressionSyntax ||
assignedValue is ImplicitArrayCreationExpressionSyntax ||
assignedValue is InitializerExpressionSyntax)
{
this.values.Add(assignedValue);
return(true);
}
var argument = assignedValue.Parent as ArgumentSyntax;
if (argument?.RefOrOutKeyword.IsKind(SyntaxKind.OutKeyword) == true)
{
var invocation = assignedValue.FirstAncestor <InvocationExpressionSyntax>();
var invokedMethod = this.semanticModel.GetSymbolSafe(invocation, this.cancellationToken);
if (invokedMethod == null ||
invokedMethod.DeclaringSyntaxReferences.Length == 0)
{
this.values.Add(invocation);
return(true);
}
var before = this.values.Count;
foreach (var reference in invokedMethod.DeclaringSyntaxReferences)
{
var methodDeclaration = reference.GetSyntax(this.cancellationToken) as MethodDeclarationSyntax;
if (methodDeclaration.TryGetMatchingParameter(argument, out ParameterSyntax parameter))
{
using (var pooled = AssignedValueWalker.Create(this.semanticModel.GetDeclaredSymbolSafe(parameter, this.cancellationToken), this.semanticModel, this.cancellationToken))
{
pooled.Item.HandleInvoke(invokedMethod, invocation.ArgumentList);
return(this.AddManyRecursively(pooled.Item));
}
}
}
return(before != this.values.Count);
}
if (assignedValue is BinaryExpressionSyntax binaryExpression)
{
switch (binaryExpression.Kind())
{
case SyntaxKind.CoalesceExpression:
var left = this.AddRecursiveValues(binaryExpression.Left);
var right = this.AddRecursiveValues(binaryExpression.Right);
return(left || right);
case SyntaxKind.AsExpression:
return(this.AddRecursiveValues(binaryExpression.Left));
default:
return(false);
}
}
if (assignedValue is CastExpressionSyntax cast)
{
return(this.AddRecursiveValues(cast.Expression));
}
if (assignedValue is ConditionalExpressionSyntax conditional)
{
var whenTrue = this.AddRecursiveValues(conditional.WhenTrue);
var whenFalse = this.AddRecursiveValues(conditional.WhenFalse);
return(whenTrue || whenFalse);
}
if (assignedValue is AwaitExpressionSyntax @await)
{
using (var pooled = ReturnValueWalker.Create(@await, Search.Recursive, this.semanticModel, this.cancellationToken))
{
return(this.AddManyRecursively(pooled.Item));
}
}
if (assignedValue is ElementAccessExpressionSyntax)
{
this.values.Add(assignedValue);
return(true);
}
var symbol = this.semanticModel.GetSymbolSafe(assignedValue, this.cancellationToken);
if (symbol == null)
{
return(false);
}
if (symbol is IFieldSymbol)
{
this.values.Add(assignedValue);
return(true);
}
if (symbol is IParameterSymbol)
{
this.values.Add(assignedValue);
using (var pooled = AssignedValueWalker.Create(assignedValue, this.semanticModel, this.cancellationToken))
{
return(this.AddManyRecursively(pooled.Item));
}
}
if (symbol is ILocalSymbol)
{
using (var pooled = AssignedValueWalker.Create(assignedValue, this.semanticModel, this.cancellationToken))
{
return(this.AddManyRecursively(pooled.Item));
}
}
if (symbol is IPropertySymbol property)
{
if (property.DeclaringSyntaxReferences.Length == 0)
{
this.values.Add(assignedValue);
return(true);
}
using (var returnValues = ReturnValueWalker.Create(assignedValue, Search.Recursive, this.semanticModel, this.cancellationToken))
{
return(this.AddManyRecursively(returnValues.Item));
}
}
if (symbol is IMethodSymbol method)
{
if (method.DeclaringSyntaxReferences.Length == 0)
{
this.values.Add(assignedValue);
return(true);
}
using (var pooled = ReturnValueWalker.Create(assignedValue, Search.Recursive, this.semanticModel, this.cancellationToken))
{
return(this.AddManyRecursively(pooled.Item));
}
}
return(false);
}
private static bool MustBeHandled(
ExpressionSyntax node,
SemanticModel semanticModel,
CancellationToken cancellationToken)
{
if (node.Parent is AnonymousFunctionExpressionSyntax ||
node.Parent is UsingStatementSyntax ||
node.Parent is EqualsValueClauseSyntax ||
node.Parent is ReturnStatementSyntax ||
node.Parent is ArrowExpressionClauseSyntax)
{
return(false);
}
if (Disposable.IsCreation(node, semanticModel, cancellationToken)
.IsEither(Result.No, Result.Unknown))
{
return(false);
}
if (node.Parent is StatementSyntax)
{
return(true);
}
if (node.Parent is ArgumentSyntax argument)
{
if (argument.Parent.Parent is InvocationExpressionSyntax invocation)
{
using (var returnWalker = ReturnValueWalker.Create(invocation, Search.Recursive, semanticModel, cancellationToken))
{
foreach (var returnValue in returnWalker.Item)
{
if (MustBeHandled(returnValue, semanticModel, cancellationToken))
{
return(true);
}
}
}
return(false);
}
if (argument.Parent.Parent is ObjectCreationExpressionSyntax)
{
if (TryGetAssignedFieldOrProperty(argument, semanticModel, cancellationToken, out ISymbol member, out IMethodSymbol ctor) &&
member != null)
{
var initializer = argument.FirstAncestorOrSelf <ConstructorInitializerSyntax>();
if (initializer != null)
{
if (semanticModel.GetDeclaredSymbolSafe(initializer.Parent, cancellationToken) is IMethodSymbol chainedCtor &&
chainedCtor.ContainingType != member.ContainingType)
{
if (Disposable.TryGetDisposeMethod(chainedCtor.ContainingType, Search.TopLevel, out IMethodSymbol disposeMethod))
{
return(!Disposable.IsMemberDisposed(member, disposeMethod, semanticModel, cancellationToken));
}
}
}
if (Disposable.IsMemberDisposed(member, ctor.ContainingType, semanticModel, cancellationToken)
.IsEither(Result.Yes, Result.Maybe))
{
return(false);
}
return(true);
}
return(ctor?.ContainingType != KnownSymbol.StreamReader &&
ctor?.ContainingType != KnownSymbol.CompositeDisposable);
}
}
return(false);
}
private static bool IsReturned(ILocalSymbol symbol, BlockSyntax block, SemanticModel semanticModel, CancellationToken cancellationToken)
{
using (var pooled = ReturnValueWalker.Create(block, Search.TopLevel, semanticModel, cancellationToken))
{
foreach (var value in pooled.Item)
{
var returnedSymbol = semanticModel.GetSymbolSafe(value, cancellationToken);
if (SymbolComparer.Equals(symbol, returnedSymbol))
{
return(true);
}
if (value is ObjectCreationExpressionSyntax objectCreation)
{
if (objectCreation.ArgumentList != null)
{
foreach (var argument in objectCreation.ArgumentList.Arguments)
{
var arg = semanticModel.GetSymbolSafe(argument.Expression, cancellationToken);
if (SymbolComparer.Equals(symbol, arg))
{
return(true);
}
}
}
if (objectCreation.Initializer != null)
{
foreach (var argument in objectCreation.Initializer.Expressions)
{
var arg = semanticModel.GetSymbolSafe(argument, cancellationToken);
if (SymbolComparer.Equals(symbol, arg))
{
return(true);
}
}
}
}
if (value is InvocationExpressionSyntax invocation)
{
if (returnedSymbol == KnownSymbol.RxDisposable.Create &&
invocation.ArgumentList != null &&
invocation.ArgumentList.Arguments.TryGetSingle(out ArgumentSyntax argument))
{
var body = (argument.Expression as ParenthesizedLambdaExpressionSyntax)?.Body;
using (var pooledInvocations = InvocationWalker.Create(body))
{
foreach (var candidate in pooledInvocations.Item.Invocations)
{
if (Disposable.IsDisposing(candidate, symbol, semanticModel, cancellationToken))
{
return(true);
}
}
}
}
}
}
}
return(false);
}
