private static void Handle(SyntaxNodeAnalysisContext context)
{
if (context.IsExcludedFromAnalysis())
{
return;
}
if (context.Node is AccessorDeclarationSyntax setter &&
setter.Body == null &&
context.ContainingSymbol is IMethodSymbol setMethod &&
setMethod.DeclaredAccessibility == Accessibility.Private &&
setMethod.AssociatedSymbol is IPropertySymbol property &&
!property.IsIndexer)
{
using (var walker = MutationWalker.For(property, context.SemanticModel, context.CancellationToken))
{
foreach (var value in walker.All())
{
if (MeansPropertyIsMutable(value))
{
return;
}
}
}
context.ReportDiagnostic(Diagnostic.Create(Descriptor, setter.GetLocation()));
}
}
private static bool ShouldUseParameter(SyntaxNodeAnalysisContext context, ISymbol left, ExpressionSyntax expression)
{
if (expression.FirstAncestor <AnonymousFunctionExpressionSyntax>() != null)
{
if (left is IFieldSymbol field &&
!field.IsReadOnly)
{
return(false);
}
if (left is IPropertySymbol property &&
!property.IsGetOnly())
{
return(false);
}
}
return(TryGetIdentifier(expression, out var identifierName) &&
identifierName.IsSymbol(left, context.SemanticModel, context.CancellationToken) &&
IsMutatedOnceBefore());
bool IsMutatedOnceBefore()
{
if (expression.TryFirstAncestor(out StatementSyntax statement))
{
using (var walker = MutationWalker.For(left, context.SemanticModel, context.CancellationToken))
{
return(walker.TrySingle(out var single) &&
single.TryFirstAncestor(out StatementSyntax singleStatement) &&
singleStatement.IsExecutedBefore(statement) == ExecutedBefore.Yes);
}
}
return(false);
}
}
