initial commit

Author: nytian

src/Analyzers/Orchestration/OrchestrationAnalyzer.cs

@@ -141,7 +141,14 @@ public override void Initialize(AnalysisContext context)
                     case IMethodReferenceOperation methodReferenceOperation:
                         // use the method reference as the method symbol
                         methodSymbol = methodReferenceOperation.Method;
-                        methodSyntax = methodReferenceOperation.Method.DeclaringSyntaxReferences.First().GetSyntax();
+
+                        // Only get syntax for methods in the current project (skip external assemblies)
+                        // If IsEmpty (external method), methodSyntax stays null and we skip analysis below
+                        if (!methodReferenceOperation.Method.DeclaringSyntaxReferences.IsEmpty)
+                        {
+                            methodSyntax = methodReferenceOperation.Method.DeclaringSyntaxReferences.First().GetSyntax();
+                        }
+
                         break;
                     default:
                         break;

src/Analyzers/RoslynExtensions.cs

@@ -115,6 +115,13 @@ public static bool BaseTypeIsConstructedFrom(this INamedTypeSymbol symbol, IType
     /// <returns>The collection of syntax nodes of a given method symbol.</returns>
     public static IEnumerable<MethodDeclarationSyntax> GetSyntaxNodes(this IMethodSymbol methodSymbol)
     {
+        // If the method has no syntax references (e.g., extension methods from external assemblies),
+        // return empty to skip analysis rather than throwing ArgumentException.
+        if (methodSymbol.DeclaringSyntaxReferences.IsEmpty)
+        {
+            return Enumerable.Empty<MethodDeclarationSyntax>();
+        }
+
         return methodSymbol.DeclaringSyntaxReferences.Select(r => r.GetSyntax()).OfType<MethodDeclarationSyntax>();
     }
 
@@ -155,6 +162,13 @@ public static bool IsEqualTo(this IMethodSymbol methodSymbol, INamedTypeSymbol?
     /// <returns>The Diagnostic based on the symbol location.</returns>
     public static Diagnostic BuildDiagnostic(DiagnosticDescriptor descriptor, ISymbol symbol, params string[] messageArgs)
     {
+        // If the symbol has no syntax references (e.g., symbols from external assemblies),
+        // fall back to using the symbol's location directly.
+        if (symbol.DeclaringSyntaxReferences.IsEmpty)
+        {
+            return Diagnostic.Create(descriptor, symbol.Locations.FirstOrDefault() ?? Location.None, messageArgs);
+        }
+
         return BuildDiagnostic(descriptor, symbol.DeclaringSyntaxReferences.First().GetSyntax(), messageArgs);
     }