public static void AnalyzeInvocationExpression(SyntaxNodeAnalysisContext context)
{
var invocation = (InvocationExpressionSyntax)context.Node;
ExpressionSyntax expression = invocation.Expression;
if (expression?.IsKind(SyntaxKind.SimpleMemberAccessExpression) == true)
{
var memberAccess = (MemberAccessExpressionSyntax)expression;
ArgumentListSyntax argumentList = invocation.ArgumentList;
if (argumentList != null)
{
SeparatedSyntaxList <ArgumentSyntax> arguments = argumentList.Arguments;
if (arguments.Any())
{
SimpleNameSyntax name = memberAccess.Name;
if (name?.Identifier.ValueText == "Join")
{
SemanticModel semanticModel = context.SemanticModel;
CancellationToken cancellationToken = context.CancellationToken;
MethodInfo info;
if (semanticModel.TryGetMethodInfo(invocation, out info, cancellationToken) &&
info.IsName("Join") &&
info.IsContainingType(SpecialType.System_String) &&
info.IsPublic &&
info.IsStatic &&
info.IsReturnType(SpecialType.System_String) &&
!info.IsGenericMethod &&
!info.IsExtensionMethod)
{
ImmutableArray <IParameterSymbol> parameters = info.Parameters;
if (parameters.Length == 2 &&
parameters[0].Type.IsString())
{
IParameterSymbol parameter = parameters[1];
if (parameter.IsParamsOf(SpecialType.System_String, SpecialType.System_Object) ||
parameter.Type.IsConstructedFromIEnumerableOfT())
{
ArgumentSyntax firstArgument = arguments.First();
ExpressionSyntax argumentExpression = firstArgument.Expression;
if (argumentExpression != null &&
CSharpUtility.IsEmptyString(argumentExpression, semanticModel, cancellationToken) &&
!invocation.ContainsDirectives(TextSpan.FromBounds(invocation.SpanStart, firstArgument.Span.End)))
{
context.ReportDiagnostic(
DiagnosticDescriptors.CallStringConcatInsteadOfStringJoin,
name);
}
}
}
}
}
}
}
}
}
