CSharp: More default parameter fixes

- Expression generation for `ConstructorReference` now also recursively
calls `VisitExpression` for the argument if only one argument is
detected. This allows correct overload generation for functions taking
a variable as the default parameter value.
- Default parameters of pointer-to-enumeration types are now correctly
generated similar to primitive types.

Author: trungnt2910

src/AST/TypeExtensions.cs

@@ -92,6 +92,25 @@ public static bool IsPointerToPrimitiveType(this Type t, PrimitiveType primitive
             return ptr.Pointee.IsPrimitiveType(primitive);
         }
 
+        public static bool IsPointerToEnum(this Type t)
+        {
+            var ptr = t as PointerType;
+            if (ptr == null)
+                return false;
+            return ptr.Pointee.IsEnumType();
+        }
+
+        public static bool IsPointerToEnum(this Type t, out Enumeration @enum)
+        {
+            var ptr = t as PointerType;
+            if (ptr == null)
+            {
+                @enum = null;
+                return false;
+            }
+            return ptr.Pointee.TryGetEnum(out @enum);
+        }
+
         public static bool IsPointerTo<T>(this Type t, out T type) where T : Type
         {
             var pointee = t.GetPointee();

src/Generator/Generators/CSharp/CSharpExpressionPrinter.cs

@@ -68,8 +68,8 @@ public string VisitExpression(ExpressionObsolete expr)
                 case StatementClass.ConstructorReference:
                     var constructorExpr = (CXXConstructExprObsolete)expr;
                     if (constructorExpr.Arguments.Count == 1 &&
-                        constructorExpr.Arguments[0].Declaration is Enumeration.Item)
-                        return constructorExpr.Arguments[0].Declaration.Visit(typePrinter).Type;
+                        constructorExpr.Arguments[0].Class != StatementClass.Any)
+                        return VisitExpression(constructorExpr.Arguments[0]);
                     goto default;
                 default:
                     return expr.String;

src/Generator/Generators/CSharp/CSharpSources.cs

@@ -2783,7 +2783,7 @@ private bool GenerateMethodBody(Class @class, Method method,
 
         private string OverloadParamNameWithDefValue(Parameter p, ref int index)
         {
-            return p.Type.IsPointerToPrimitiveType() && p.Usage == ParameterUsage.InOut && p.HasDefaultValue
+            return (p.Type.IsPointerToPrimitiveType() || p.Type.IsPointerToEnum()) && p.Usage == ParameterUsage.InOut && p.HasDefaultValue
                 ? "ref param" + index++
                 : ExpressionPrinter.VisitParameter(p);
         }
@@ -2802,13 +2802,15 @@ private void GenerateOverloadCall(Function function)
             for (int i = 0, j = 0; i < function.Parameters.Count; i++)
             {
                 var parameter = function.Parameters[i];
-                PrimitiveType primitiveType;
+                PrimitiveType primitiveType = PrimitiveType.Null;
+                Enumeration enumeration = null;
                 if (parameter.Kind == ParameterKind.Regular && parameter.Ignore &&
-                    parameter.Type.IsPointerToPrimitiveType(out primitiveType) &&
+                        (parameter.Type.IsPointerToPrimitiveType(out primitiveType) ||
+                        parameter.Type.IsPointerToEnum(out enumeration)) &&
                     parameter.Usage == ParameterUsage.InOut && parameter.HasDefaultValue)
                 {
                     var pointeeType = ((PointerType)parameter.Type).Pointee.ToString();
-                    WriteLine($@"{pointeeType} param{j++} = {(primitiveType == PrimitiveType.Bool ? "false" : "0")};");
+                    WriteLine($@"{pointeeType} param{j++} = {(primitiveType == PrimitiveType.Bool ? "false" : $"({pointeeType})0")};");
                 }
             }
 

tests/dotnet/Common/Common.Tests.cs

@@ -929,7 +929,7 @@ public void TestStdString()
         // when C++ memory is deleted, it's only marked as free but not immediadely freed
         // this can hide memory bugs while marshalling
         // so let's use a long string to increase the chance of a crash right away
-        const string t = @"This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. 
+        const string t = @"This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string.
 This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string.
 This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string.
 This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string.
@@ -951,7 +951,7 @@ public void TestStdStringPassedByValue()
         // when C++ memory is deleted, it's only marked as free but not immediadely freed
         // this can hide memory bugs while marshalling
         // so let's use a long string to increase the chance of a crash right away
-        const string t = @"This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. 
+        const string t = @"This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string.
 This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string.
 This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string.
 This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string. This is a very long string.
@@ -1147,6 +1147,17 @@ public void TestReturnByValueWithReturnParam()
         }
     }
 
+    [Test]
+    public void TestDefaultParams()
+    {
+        Common.FunctionWithFlagsAsDefaultParameter();
+        Common.FunctionWithConstFlagsAsDefaultParameter();
+        Common.FunctionWithPointerToEnumAsDefaultParameter();
+
+        Assert.That(Common.FunctionWithNonPrimitiveAsDefaultParameter(),
+            Is.EqualTo(Common.FunctionWithNonPrimitiveAsDefaultParameter(Common.DefaultBar)));
+    }
+
     [Test, Ignore("This was exposed by another bug and doesn't work yet.")]
     public void TestFreeFunctionReturnByValue()
     {

tests/dotnet/Common/Common.cpp

@@ -1282,3 +1282,14 @@ void DLL_API FunctionWithFlagsAsDefaultParameter(int defaultParam)
 void DLL_API FunctionWithConstFlagsAsDefaultParameter(int defaultParam)
 {
 }
+
+void DLL_API FunctionWithPointerToEnumAsDefaultParameter(Enum* defaultParam1, int* defaultParam2)
+{
+}
+
+DLL_API struct Bar DefaultBar;
+
+DLL_API struct Bar* FunctionWithNonPrimitiveAsDefaultParameter(struct Bar& defaultParam)
+{
+    return defaultParam.returnPointerToValueType();
+}

tests/dotnet/Common/Common.h

@@ -1575,3 +1575,9 @@ const int ConstFlag2 = 2;
 const int ConstFlag3 = 4;
 
 void DLL_API FunctionWithConstFlagsAsDefaultParameter(int defaultParam = ConstFlag1 | ConstFlag2 | ConstFlag3);
+
+void DLL_API FunctionWithPointerToEnumAsDefaultParameter(Enum* defaultParam1 = NULL, int* defaultParam2 = NULL);
+
+extern DLL_API struct Bar DefaultBar;
+
+DLL_API struct Bar* FunctionWithNonPrimitiveAsDefaultParameter(struct Bar& defaultParam = DefaultBar);