public static void Analyze(
SyntaxNodeAnalysisContext context,
SimpleMemberInvocationExpressionInfo invocationInfo)
{
InvocationExpressionSyntax invocationExpression = invocationInfo.InvocationExpression;
if (invocationInfo.Name.SpanOrTrailingTriviaContainsDirectives())
{
return;
}
if (invocationInfo.ArgumentList.SpanOrLeadingTriviaContainsDirectives())
{
return;
}
SemanticModel semanticModel = context.SemanticModel;
CancellationToken cancellationToken = context.CancellationToken;
ExtensionMethodSymbolInfo extensionInfo = semanticModel.GetExtensionMethodInfo(invocationExpression, cancellationToken);
if (extensionInfo.Symbol == null)
{
return;
}
if (!SymbolUtility.IsLinqSelect(extensionInfo.Symbol, semanticModel, allowImmutableArrayExtension: true))
{
return;
}
ITypeSymbol typeArgument = extensionInfo.ReducedSymbolOrSymbol.TypeArguments[0];
if (!typeArgument.IsReferenceType)
{
return;
}
if (typeArgument.SpecialType == SpecialType.System_Object)
{
return;
}
ExpressionSyntax expression = invocationExpression.ArgumentList?.Arguments.Last().Expression;
SingleParameterLambdaExpressionInfo lambdaInfo = SyntaxInfo.SingleParameterLambdaExpressionInfo(expression);
if (!lambdaInfo.Success)
{
return;
}
CastExpressionSyntax castExpression = GetCastExpression(lambdaInfo.Body);
if (castExpression == null)
{
return;
}
if (!(castExpression.Expression is IdentifierNameSyntax identifierName))
{
return;
}
if (!string.Equals(lambdaInfo.Parameter.Identifier.ValueText, identifierName.Identifier.ValueText, StringComparison.Ordinal))
{
return;
}
var castSymbol = semanticModel.GetSymbol(castExpression, cancellationToken) as IMethodSymbol;
if (castSymbol?.MethodKind == MethodKind.Conversion)
{
return;
}
context.ReportDiagnostic(
DiagnosticDescriptors.CallCastInsteadOfSelect,
Location.Create(invocationExpression.SyntaxTree, TextSpan.FromBounds(invocationInfo.Name.SpanStart, invocationExpression.Span.End)));
}