diff --git a/src/AST/FunctionExtensions.cs b/src/AST/FunctionExtensions.cs
index 17a1c9ae4b..ce37ec67f5 100644
--- a/src/AST/FunctionExtensions.cs
+++ b/src/AST/FunctionExtensions.cs
@@ -21,7 +21,7 @@ public static IList<Parameter> GatherInternalParams(this Function function,
                 @params.Add(new Parameter
                     {
                         QualifiedType = pointer,
-                        Name = "instance",
+                        Name = "__instance",
                         Namespace = function
                     });
             }
@@ -32,7 +32,7 @@ public static IList<Parameter> GatherInternalParams(this Function function,
                 @params.Add(new Parameter
                     {
                         QualifiedType = pointer,
-                        Name = "instance",
+                        Name = "__instance",
                         Namespace = function
                     });
             }
@@ -57,7 +57,7 @@ public static IList<Parameter> GatherInternalParams(this Function function,
                     @params.Add(new Parameter
                         {
                             QualifiedType = pointer,
-                            Name = "instance",
+                            Name = "__instance",
                             Namespace = function
                         });
                 }
diff --git a/src/Generator/Generators/CSharp/CSharpSources.cs b/src/Generator/Generators/CSharp/CSharpSources.cs
index 7f80228c85..ee3c502c95 100644
--- a/src/Generator/Generators/CSharp/CSharpSources.cs
+++ b/src/Generator/Generators/CSharp/CSharpSources.cs
@@ -1786,12 +1786,13 @@ private void GenerateVTableMethodDelegates(Class @class, Method method)
                 string.Join(", ", @params));
             WriteOpenBraceAndIndent();
 
-            WriteLine("if (!NativeToManagedMap.ContainsKey(instance))");
+            WriteLine($"if (!NativeToManagedMap.ContainsKey({Helpers.InstanceField}))");
             WriteLineIndent("throw new global::System.Exception(\"No managed instance was found\");");
             NewLine();
 
             var printedClass = @class.Visit(TypePrinter);
-            WriteLine($"var {Helpers.TargetIdentifier} = ({printedClass}) NativeToManagedMap[instance];");
+            WriteLine($@"var {Helpers.TargetIdentifier} = ({
+                printedClass}) NativeToManagedMap[{Helpers.InstanceField}];");
             WriteLine("if ({0}.{1})", Helpers.TargetIdentifier, Helpers.OwnsNativeInstanceIdentifier);
             WriteLineIndent("{0}.SetupVTables();", Helpers.TargetIdentifier);
             GenerateVTableManagedCall(method);
diff --git a/tests/Common/Common.Tests.cs b/tests/Common/Common.Tests.cs
index a07d449312..b41875a9fe 100644
--- a/tests/Common/Common.Tests.cs
+++ b/tests/Common/Common.Tests.cs
@@ -55,6 +55,7 @@ public unsafe void TestCodeGeneration()
         ItemsDifferByCase itemsDifferByCase = ItemsDifferByCase.Case_a;
         itemsDifferByCase = ItemsDifferByCase.CaseA;
         itemsDifferByCase.GetHashCode();
+        new AmbiguousParamNames(0, 0).Dispose();
         Common.SMallFollowedByCapital();
         Common.IntegerOverload(0);
         Common.IntegerOverload((uint) 0);
diff --git a/tests/Common/Common.cpp b/tests/Common/Common.cpp
index 0f394c9af6..de39359740 100644
--- a/tests/Common/Common.cpp
+++ b/tests/Common/Common.cpp
@@ -848,7 +848,7 @@ HasOverloadsWithDifferentPointerKindsToSameType::~HasOverloadsWithDifferentPoint
 {
 }
 
-void HasOverloadsWithDifferentPointerKindsToSameType::overload(int& in)
+void HasOverloadsWithDifferentPointerKindsToSameType::overload(int& i)
 {
 }
 
@@ -991,6 +991,14 @@ void DerivedFromSecondaryBaseWithIgnoredVirtualMethod::ignored(const IgnoredType
 {
 }
 
+AmbiguousParamNames::AmbiguousParamNames(int instance, int in)
+{
+}
+
+AmbiguousParamNames::~AmbiguousParamNames()
+{
+}
+
 void integerOverload(int i)
 {
 }
diff --git a/tests/Common/Common.h b/tests/Common/Common.h
index 911cfbe03c..7a31bf6d04 100644
--- a/tests/Common/Common.h
+++ b/tests/Common/Common.h
@@ -1310,7 +1310,7 @@ class DLL_API HasOverloadsWithDifferentPointerKindsToSameType
 public:
     HasOverloadsWithDifferentPointerKindsToSameType();
     ~HasOverloadsWithDifferentPointerKindsToSameType();
-    void overload(int& in);
+    void overload(int& i);
     void overload(int&& i);
     void overload(const int& i);
     void overload(const Foo& rx, int from = -1);
@@ -1394,6 +1394,13 @@ class DLL_API DerivedFromSecondaryBaseWithIgnoredVirtualMethod : public Foo, pub
     void ignored(const IgnoredType& ignoredParam);
 };
 
+class DLL_API AmbiguousParamNames
+{
+public:
+    AmbiguousParamNames(int instance, int in);
+    ~AmbiguousParamNames();
+};
+
 template<typename T> void TemplatedFunction(T type)
 {
 
@@ -1403,7 +1410,7 @@ inline namespace InlineNamespace
 {
     void FunctionInsideInlineNamespace()
     {
-        
+
     }
 }