internal static bool TrySingleReturned(AccessorDeclarationSyntax getter, [NotNullWhen(true)] out ExpressionSyntax?result)
{
if (getter.ExpressionBody is { } getterExpressionBody)
{
result = getterExpressionBody.Expression;
return(result != null);
}
if (getter.Body is { } body)
{
if (body.Statements.Count == 0)
{
result = null;
return(false);
}
if (body.Statements.TrySingle(out var statement))
{
if (statement is ReturnStatementSyntax returnStatement)
{
result = returnStatement.Expression;
return(result != null);
}
}
return(ReturnExpressionsWalker.TryGetSingle(getter, out result));
}
result = null;
return(false);
}
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 &&
IsProperty(expressionBody.Expression, property))
{
context.ReportDiagnostic(Diagnostic.Create(INPC015PropertyIsRecursive.Descriptor, expressionBody.Expression.GetLocation(), "Expression body returns property, infinite recursion"));
}
if (propertyDeclaration.TryGetGetter(out var getter))
{
using (var returnWalker = ReturnExpressionsWalker.Borrow(getter))
{
if (returnWalker.ReturnValues.TryFirst(x => IsProperty(x, property), out var recursiveReturnValue))
{
context.ReportDiagnostic(Diagnostic.Create(INPC015PropertyIsRecursive.Descriptor, recursiveReturnValue.GetLocation(), "Getter returns property, infinite recursion"));
}
}
}
if (propertyDeclaration.TryGetSetter(out var setter))
{
using (var assignmentWalker = AssignmentWalker.Borrow(setter))
{
if (assignmentWalker.Assignments.TryFirst(x => IsProperty(x.Left, property), out var recursiveAssignment))
{
context.ReportDiagnostic(Diagnostic.Create(INPC015PropertyIsRecursive.Descriptor, recursiveAssignment.Left.GetLocation(), "Setter assigns property, infinite recursion"));
}
if (getter != null)
{
if (property.ContainingType.Is(KnownSymbol.INotifyPropertyChanged) &&
Property.ShouldNotify(propertyDeclaration, property, context.SemanticModel, context.CancellationToken))
{
context.ReportDiagnostic(Diagnostic.Create(INPC002MutablePublicPropertyShouldNotify.Descriptor, propertyDeclaration.GetLocation(), property.Name));
}
if (assignmentWalker.Assignments.TrySingle(out var singleAssignment) &&
ReturnExpressionsWalker.TryGetSingle(getter, out var singleReturnValue) &&
!MemberPath.Uses(singleAssignment.Left, singleReturnValue, context))
{
context.ReportDiagnostic(Diagnostic.Create(INPC010GetAndSetSame.Descriptor, propertyDeclaration.GetLocation()));
}
}
}
}
}
}