public override void Initialize(AnalysisContext context)
{
var cache = new WellKnownTypeCache();
context.RegisterSyntaxNodeAction(ctx => AnalyzeStatementExpression(cache, ctx), SyntaxKind.ExpressionStatement);
context.RegisterSyntaxNodeAction(ctx => AnalyzeImplicitConversion(cache, ctx), SyntaxKind.MethodDeclaration);
}
private void AnalyzeImplicitConversion(WellKnownTypeCache cache, SyntaxNodeAnalysisContext context)
{
var visitor = new ImplicitConversionWalker()
{
cache = cache, context = context
};
visitor.Visit(context.Node);
}
public void AnalyzeStatementExpression(WellKnownTypeCache cache, SyntaxNodeAnalysisContext context)
{
// If we encounter "await e;" where the result type of the await is a Task ...
var expression = (context.Node as ExpressionStatementSyntax).Expression;
if (expression == null)
{
return;
}
if (expression.Kind() != SyntaxKind.AwaitExpression)
{
return;
}
var typeInfo = context.SemanticModel.GetTypeInfo(expression);
var type = typeInfo.Type as INamedTypeSymbol;
if (type == null)
{
return;
}
if ((object)type != cache.GetTask(context.SemanticModel) && (object)type.ConstructedFrom != cache.GetGenericTask(context.SemanticModel))
{
return;
}
// and if "e" didn't have the form "Task.WhenAny(...)" ...
var awaitOperand = (expression as AwaitExpressionSyntax).Expression;
if (awaitOperand.Kind() == SyntaxKind.InvocationExpression)
{
var targetNode = (awaitOperand as InvocationExpressionSyntax).Expression;
if (targetNode != null)
{
var targetSymbol = context.SemanticModel.GetSymbolInfo(targetNode).Symbol;
if (targetSymbol != null)
{
if ((object)targetSymbol.ContainingType == cache.GetTask(context.SemanticModel) && targetSymbol.Name == "WhenAny")
{
return;
}
}
}
}
context.ReportDiagnostic(Diagnostic.Create(AwaitTaskTask, context.Node.GetLocation(), type.Name));
}
