Keep the original pointer that originated the AST declaration node and check if we have already processed the method in WalkMethodCXX (if so, just return the already existing declaration).

We depend on this to get the right method instance when walking through the vtable methods.

src/AST/Declaration.cs

@@ -193,6 +193,9 @@ namespace CppSharp.AST
         // List of preprocessed entities attached to this declaration.
         public IList<PreprocessedEntity> PreprocessedEntities; 
 
+        // Pointer to the original declaration from Clang.
+        public IntPtr OriginalPtr;
+
         protected Declaration()
         {
             IgnoreFlags = IgnoreFlags.None;

src/Parser/Parser.cpp

@@ -744,6 +744,20 @@ CppSharp::AST::Method^ Parser::WalkMethodCXX(clang::CXXMethodDecl* MD)
 {
     using namespace clang;
 
+    // We could be in a redeclaration, so process the primary context.
+    if (MD->getPrimaryContext() != MD)
+        return WalkMethodCXX(cast<CXXMethodDecl>(MD->getPrimaryContext()));
+
+    auto RD = MD->getParent();
+    auto Class = WalkRecordCXX(RD);
+
+    // Check for an already existing method that came from the same declaration.
+    for each (CppSharp::AST::Method^ Method in Class->Methods)
+    {
+        if (Method->OriginalPtr.ToPointer() == MD)
+            return Method;
+    }
+
     DeclarationName Name = MD->getDeclName();
 
     CppSharp::AST::Method^ Method = gcnew CppSharp::AST::Method();
@@ -1466,6 +1480,7 @@ void Parser::WalkFunction(clang::FunctionDecl* FD, CppSharp::AST::Function^ F,
     auto NS = GetNamespace(FD);
     assert(NS && "Expected a valid namespace");
 
+    F->OriginalPtr = System::IntPtr(FD);
     F->Name = marshalString<E_UTF8>(FD->getNameAsString());
     F->Namespace = NS;
     F->IsVariadic = FD->isVariadic();