Generate valid C# for returned const char*&

Signed-off-by: Dimitar Dobrev <dpldobrev@protonmail.com>

src/Generator/Generators/CSharp/CSharpMarshal.cs

@@ -146,8 +146,10 @@ namespace CppSharp.Generators.CSharp
 
             var pointee = pointer.Pointee.Desugar();
             var finalPointee = pointer.GetFinalPointee().Desugar();
+            var type = Context.ReturnType.Type.Desugar(
+                resolveTemplateSubstitution: false);
             PrimitiveType primitive;
-            if ((pointee.IsConstCharString() && isRefParam) ||
+            if ((pointee.IsConstCharString() && (isRefParam || type.IsReference())) ||
                 (!finalPointee.IsPrimitiveType(out primitive) &&
                  !finalPointee.IsEnumType()))
                 return pointer.QualifiedPointee.Visit(this);
@@ -162,8 +164,6 @@ namespace CppSharp.Generators.CSharp
                 primitive == PrimitiveType.Char)
                 Context.Return.Write($"({pointer}) ");
 
-            var type = Context.ReturnType.Type.Desugar(
-                resolveTemplateSubstitution: false);
             if (Context.Function != null &&
                 Context.Function.OperatorKind == CXXOperatorKind.Subscript)
             {

src/Generator/Types/Std/Stdlib.cs

@@ -218,9 +218,16 @@ namespace CppSharp.Types.Std
             if (Equals(encoding, Encoding.ASCII))
                 encoding = Context.Options.Encoding;
 
-            string returnVarName = ctx.Function != null &&
-                ctx.Function.ReturnType.Type.Desugar().IsAddress() ?
-                $"(global::System.IntPtr) {ctx.ReturnVarName}" : ctx.ReturnVarName;
+            string returnVarName = ctx.ReturnVarName;
+            if (ctx.Function != null)
+            {
+                Type returnType = ctx.Function.ReturnType.Type.Desugar();
+                if (returnType.IsAddress() &&
+                    returnType.GetPointee().Desugar().IsAddress())
+                {
+                    returnVarName = $"new global::System.IntPtr(*{returnVarName})";
+                }
+            }
 
             if (Equals(encoding, Encoding.ASCII))
             {

tests/CSharp/CSharp.cpp

@@ -1560,7 +1560,7 @@ char* returnCharPointer()
     return 0;
 }
 
-const char* takeConstCharStarRef(const char*& c)
+const char*& takeConstCharStarRef(const char*& c)
 {
     return c;
 }

tests/CSharp/CSharp.h

@@ -1305,7 +1305,7 @@ public:
 
 DLL_API void va_listFunction(va_list v);
 DLL_API char* returnCharPointer();
-DLL_API const char* takeConstCharStarRef(const char*& c);
+DLL_API const char*& takeConstCharStarRef(const char*& c);
 
 struct {
     struct {