Fix FunctionToStaticMethod bug

src/Generator/Passes/CheckAbiParameters.cs

@@ -1,5 +1,6 @@
 using CppSharp.AST;
 using CppSharp.AST.Extensions;
+using CppSharp.Extensions;
 using System.Linq;
 
 namespace CppSharp.Passes
@@ -32,7 +33,7 @@ namespace CppSharp.Passes
 
             var isReturnIndirect = function.IsReturnIndirect || (
                     Context.ParserOptions.IsMicrosoftAbi &&
-                    function is Method &&
+                    function is Method m && m.IsNativeMethod() &&
                     !function.ReturnType.Type.Desugar().IsAddress() &&
                     function.ReturnType.Type.Desugar().TryGetDeclaration(out Class returnTypeDecl) &&
                     returnTypeDecl.IsPOD &&

src/Generator/Passes/MoveFunctionToClassPass.cs

@@ -23,7 +23,8 @@ namespace CppSharp.Passes
                 Namespace = @class,
                 OperatorKind = function.OperatorKind,
                 OriginalFunction = null,
-                IsStatic = true
+                Conversion = MethodConversionKind.FunctionToStaticMethod,
+                IsStatic = true,
             };
 
             if (method.IsOperator)

tests/CSharp/CSharp.Tests.cs

@@ -1883,4 +1883,14 @@ public unsafe class CSharpTests
             Assert.That((short)c, Is.EqualTo(100));
         }
     }
+
+    [Test]
+    public void TestFunctionToInstanceMethod()
+    {
+        Assert.That(CSharp.CSharp.TestFunctionToInstanceMethod(new FTIStruct()).A, Is.EqualTo(6));
+        Assert.That(CSharp.CSharp.TestFunctionToInstanceMethodStruct(new FTIStruct(), new FTIStruct() { A = 6 }), Is.EqualTo(6));
+        Assert.That(CSharp.CSharp.TestFunctionToInstanceMethodRefStruct(new FTIStruct(), new FTIStruct() { A = 6 }), Is.EqualTo(6));
+        Assert.That(CSharp.CSharp.TestFunctionToInstanceMethodConstStruct(new FTIStruct(), new FTIStruct() { A = 6 }), Is.EqualTo(6));
+        Assert.That(CSharp.CSharp.TestFunctionToInstanceMethodConstRefStruct(new FTIStruct(), new FTIStruct() { A = 6 }), Is.EqualTo(6));
+    }
 }

tests/CSharp/CSharp.cpp

@@ -1685,3 +1685,9 @@ const unsigned StructWithEmbeddedArrayOfStructObjectAlignmentOffsets[2]
     offsetof(StructWithEmbeddedArrayOfStructObjectAlignment, boolean),
     offsetof(StructWithEmbeddedArrayOfStructObjectAlignment, embedded_struct),
 };
+
+DLL_API FTIStruct TestFunctionToInstanceMethod(FTIStruct* bb) { return { 6 }; }
+DLL_API int TestFunctionToInstanceMethodStruct(FTIStruct* bb, FTIStruct defaultValue) { return defaultValue.a; }
+DLL_API int TestFunctionToInstanceMethodRefStruct(FTIStruct* bb, FTIStruct& defaultValue) { return defaultValue.a; }
+DLL_API int TestFunctionToInstanceMethodConstStruct(FTIStruct* bb, const FTIStruct defaultValue) { return defaultValue.a; }
+DLL_API int TestFunctionToInstanceMethodConstRefStruct(FTIStruct* bb, const FTIStruct& defaultValue) { return defaultValue.a; }

tests/CSharp/CSharp.h

@@ -1526,3 +1526,11 @@ DLL_API const char* TestCSharpString(const char* in, CS_OUT const char** out);
 DLL_API const wchar_t* TestCSharpStringWide(const wchar_t* in, CS_OUT const wchar_t** out);
 DLL_API const char16_t* TestCSharpString16(const char16_t* in, CS_OUT const char16_t** out);    
 DLL_API const char32_t* TestCSharpString32(const char32_t* in, CS_OUT const char32_t** out);
+
+struct DLL_API FTIStruct { int a; };
+
+DLL_API FTIStruct TestFunctionToInstanceMethod(FTIStruct* bb);
+DLL_API int TestFunctionToInstanceMethodStruct(FTIStruct* bb, FTIStruct defaultValue);
+DLL_API int TestFunctionToInstanceMethodRefStruct(FTIStruct* bb, FTIStruct& defaultValue);
+DLL_API int TestFunctionToInstanceMethodConstStruct(FTIStruct* bb, const FTIStruct defaultValue);
+DLL_API int TestFunctionToInstanceMethodConstRefStruct(FTIStruct* bb, const FTIStruct& defaultValue);