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src/Features/Core/Portable/Completion/Providers/ImportCompletionProvider/AbstractExtensionMethodImportCompletionProvider.cs

@@ -78,7 +78,7 @@ private static bool TryGetReceiverTypeSymbol(SyntaxContext syntaxContext, ISynta
                 _ => symbol as ITypeSymbol,
             };
 
-        private CompletionItem Convert(SerializableImportCompletionItem serializableItem) 
+        private CompletionItem Convert(SerializableImportCompletionItem serializableItem)
             => ImportCompletionItem.Create(
                 serializableItem.Name,
                 serializableItem.Arity,

src/Workspaces/Core/Portable/FindSymbols/SymbolTree/SymbolTreeInfo_Metadata.cs

@@ -229,8 +229,13 @@ private struct MetadataInfoCreator : IDisposable
             // The set of type definitions we've read out of the current metadata reader.
             private readonly List<MetadataDefinition> _allTypeDefinitions;
 
-            // Map from node represents extension method to list of possible parameter type info 
-            // (which can be more than one because we might have multiple overloads).
+            // Map from node represents extension method to list of possible parameter type info.
+            // We can have more than one if there's multiple methods with same name but different target type.
+            // e.g.
+            //
+            //      public static bool AnotherExtensionMethod1(this int x);
+            //      public static bool AnotherExtensionMethod1(this bool x);
+            //
             private MultiDictionary<MetadataNode, ParameterTypeInfo> _extensionMethodToParameterTypeInfo;
             private bool _containsExtensionsMethod;
 
@@ -368,6 +373,7 @@ private void GenerateMetadataNodes()
                     {
                         if (definition.Kind == MetadataDefinitionKind.Member)
                         {
+                            // We need to support having multiple methods with same name but different target type.
                             _extensionMethodToParameterTypeInfo.Add(childNode, definition.TargetTypeInfo);
                         }
 

src/Workspaces/Core/Portable/LanguageServices/SyntaxFactsService/ISyntaxFactsService.cs

@@ -181,9 +181,9 @@ internal interface ISyntaxFactsService : ILanguageService
         /// <param name="allowImplicitTarget">
         /// In VB, we have a member access expression with a null expression, this may be one of the
         /// following forms:
-        ///     1) new With { .a = 1, .b = .a     <-- .a refers to the anonymous type
-        ///     2) With obj : .m                  <-- .m refers to the obj type
-        ///     3) new T() With { .a = 1, .b = .a <-- 'a refers to the T type
+        ///     1) new With { .a = 1, .b = .a      .a refers to the anonymous type
+        ///     2) With obj : .m                   .m refers to the obj type
+        ///     3) new T() With { .a = 1, .b = .a  'a refers to the T type
         /// If `allowImplicitTarget` is set to true, the returned node will be set to approperiate node, otherwise, it will return null.
         /// This parameter has no affect on C# node.
         /// </param>