Handle extension methods

Author: ATrefzer

CodeParser/Parser/Parser.Phase2.cs

@@ -109,6 +109,13 @@ private void AnalyzeMethodDependencies(Solution solution, CodeElement methodElem
             AddTypeDependency(methodElement, methodSymbol.ReturnType, DependencyType.Uses);
         }
 
+        //if (methodSymbol.IsExtensionMethod)
+        //{
+        //    // The first parameter of an extension method is the extended type
+        //    var extendedType = methodSymbol.Parameters[0].Type;
+        //    AddTypeDependency(methodElement, extendedType, DependencyType.Uses);
+        //}
+
         // If this method is an interface method or an abstract method, find its implementations
         if (methodSymbol.IsAbstract || methodSymbol.ContainingType.TypeKind == TypeKind.Interface)
         {
@@ -300,11 +307,16 @@ private void AddEventUsageDependency(CodeElement sourceElement, IEventSymbol eve
         }
     }
 
-
     private void AddCallsDependency(CodeElement sourceElement, IMethodSymbol methodSymbol, SourceLocation location)
     {
         //Trace.WriteLine($"Adding call dependency: {sourceElement.Name} -> {methodSymbol.Name}");
 
+        if (methodSymbol.IsExtensionMethod)
+        {
+            // Handle calls to extension methods
+            methodSymbol = methodSymbol.ReducedFrom ?? methodSymbol;
+        }
+
         if (_symbolKeyToElementMap.TryGetValue(GetSymbolKey(methodSymbol), out var targetElement))
         {
             AddDependency(sourceElement, DependencyType.Calls, targetElement, [location]);
@@ -414,6 +426,8 @@ private void AddExternalDependency(CodeElement sourceElement, ITypeSymbol typeSy
     private void AnalyzeExpressionBody(CodeElement sourceElement, ArrowExpressionClauseSyntax expressionBody,
         SemanticModel semanticModel)
     {
+        // TODO atr. Can we just call AnalyzeMethodBody?
+        // The InvocationExpressionSyntax handles more cases here. But all other methods are also handled in AnalyzeMethodBody
         AnalyzeExpression(sourceElement, expressionBody.Expression, semanticModel);
     }
 

CodeParserTests/CodeParserApprovalTests.cs

@@ -75,7 +75,13 @@ public void FindsAllFunctions()
             "CSharpLanguage.CSharpLanguage.PinSignalView.PinSignalViewAutomationPeer..ctor",
             "CSharpLanguage.CSharpLanguage.MissingInterface.BaseStorage.Load",
             "CSharpLanguage.CSharpLanguage.MissingInterface.IStorage.Load",
-            "CSharpLanguage.CSharpLanguage.NS_Parent.NS_Child.ClassNsChild.Method"
+            "CSharpLanguage.CSharpLanguage.NS_Parent.NS_Child.ClassNsChild.Method",
+
+            // Extension method
+            "CSharpLanguage.CSharpLanguage.Extensions.Slice", 
+
+            // Called by extension method
+            "CSharpLanguage.CSharpLanguage.TheExtendedType.Do"
         };
 
 

SampleProject/CSharpLanguage/ClassUsingAnEvent.cs

@@ -15,6 +15,12 @@ void Init()
 
             x.MyEvent2 += MyEventHandler2;
 
+            var foo = new TheExtendedType();
+            foo.Slice(1, 2);
+
+
+            Extensions.Slice(foo, 1, 2);
+
 
         }
 

SampleProject/CSharpLanguage/CreatorOfGenericTypes.cs

@@ -20,6 +20,8 @@ void Create()
         {
             var x = new List<Project>();
             var y = new XmlFile<Project>();
+
+          
         }
     }
 }

SampleProject/CSharpLanguage/ExtensionMethods.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace CSharpLanguage
+{
+
+    public class TheExtendedType
+    {
+        public void Do()
+        {
+
+        }
+    }
+    public static class Extensions
+    {
+        public static void Slice(this TheExtendedType s, int start, int length)
+        {
+            s.Do();
+        }
+    }
+
+}