Extension method fix

CodeConverter/CSharp/VbNameExpander.cs

@@ -80,7 +80,7 @@ private static bool IsReceiverTypeOrDerivedTypeEnclosingType(SyntaxNode node, IM
     {
         var classType = (ITypeSymbol)node.GetEnclosingDeclaredTypeSymbol(semanticModel);
 
-        return classType.InheritsFromOrEquals(symbol.ReceiverType);
+        return classType.InheritsFromOrEquals(symbol.ReceiverType, includeInterfaces: true);
     }
 
     /// <summary>
@@ -122,9 +122,13 @@ private static bool NameCanBeExpanded(SyntaxNode node)
     private static INamedTypeSymbol GetDefaultImplicitInstance(SimpleNameSyntax node, ISymbol symbol, SemanticModel semanticModel, CancellationToken cancellationToken = default) =>
         IsQualifiableInstanceReference(symbol) && IsLeftMostQualifier(node) ? semanticModel.GetEnclosingSymbol<INamedTypeSymbol>(node.SpanStart, cancellationToken) : null;
 
+    /// <remarks>
+    /// Reduced extension methods are never members of the qualifying type, but that's not type promotion.
+    /// Treating them as such replaces the whole access with its receiver, skipping the expansion of an implicit Me receiver within it.
+    /// </remarks>
     private static bool IsTypePromotion(SyntaxNode node, ISymbol symbol, SemanticModel semanticModel)
     {
-        if (IsQualifiableInstanceReference(symbol) && node is MemberAccessExpressionSyntax maes && maes.Expression != null) {
+        if (!symbol.IsReducedExtension() && IsQualifiableInstanceReference(symbol) && node is MemberAccessExpressionSyntax maes && maes.Expression != null) {
             var qualifyingType = semanticModel.GetTypeInfo(maes.Expression).Type;
             return qualifyingType == null || !qualifyingType.ContainsMember(symbol);
         }

Tests/CSharp/MemberTests/ExtensionMethodTests.cs

@@ -31,6 +31,32 @@ public static void TestMethod2Parameters(this string str, string other)
 }");
     }
 
+    [Fact]
+    public async Task ImplicitMeExtensionCallKeepsReceiverAsync()
+    {
+        await TestConversionVisualBasicToCSharpAsync(
+            @"Imports System.Collections.Generic
+Imports System.Linq
+
+Public Class MyList
+    Inherits List(Of Integer)
+
+    Public Function Uniques() As List(Of Integer)
+        Return Distinct().ToList()
+    End Function
+End Class", @"using System.Collections.Generic;
+using System.Linq;
+
+public partial class MyList : List<int>
+{
+
+    public List<int> Uniques()
+    {
+        return this.Distinct().ToList();
+    }
+}");
+    }
+
     [Fact]
     public async Task TestExtensionMethodWithExistingImportAsync()
     {