Fixed the generated C# when an unsigned enum is assigned a negative value.

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

Author: ddobrev

build/InstallMono.sh

@@ -1,6 +1,6 @@
 OS=$(uname -s)
 if [ "$OS" == "Darwin" ]; then
-	wget -O mono.pkg https://download.mono-project.com/archive/5.2.0/macos-10-universal/MonoFramework-MDK-5.2.0.215.macos10.xamarin.universal.pkg
+	wget -O mono.pkg https://download.mono-project.com/archive/5.18.0/macos-10-universal/MonoFramework-MDK-5.18.0.240.macos10.xamarin.universal.pkg
 	sudo installer -pkg mono.pkg -target /
 	export PATH=$PATH:/Library/Frameworks/Mono.framework/Versions/Current/bin
 elif [ "$OS" == "Linux" ]; then

src/Generator/Passes/HandleDefaultParamValuesPass.cs

@@ -129,8 +129,7 @@ private bool CheckForDefaultPointer(Type desugared, ref string result)
             Class @class;
             if (desugared.GetFinalPointee().TryGetClass(out @class) && @class.IsValueType)
             {
-                result = string.Format("new {0}()",
-                    new CSharpTypePrinter(Context).VisitClassDecl(@class));
+                result = $"new {@class.Visit(new CSharpTypePrinter(Context))}()";
                 return true;
             }
 
@@ -253,15 +252,40 @@ private bool CheckForEnumValue(Type desugared, Statement statement,
             if (call != null && statement.String != "0")
             {
                 var @params = regexFunctionParams.Match(statement.String).Groups[1].Value;
-                result = TranslateEnumExpression(call, desugared, @params);
+                result = TranslateEnumExpression(desugared, @params);
+                return true;
+            }
+
+            if (desugared.TryGetEnum(out Enumeration @enum) &&
+                int.TryParse(statement.String, out int value))
+            {
+                var typePrinter = new CSharpTypePrinter(Context);
+                var printedEnum = @enum.Visit(typePrinter);
+                if (value < 0)
+                    switch (@enum.BuiltinType.Type)
+                    {
+                        case PrimitiveType.UShort:
+                        case PrimitiveType.UInt:
+                        case PrimitiveType.ULong:
+                        case PrimitiveType.ULongLong:
+                        case PrimitiveType.UInt128:
+                            result = $@"({printedEnum}) unchecked(({
+                                @enum.BuiltinType.Visit(typePrinter)}) {
+                                statement.String})";
+                            break;
+                        default:
+                            result = $"({printedEnum}) ({statement.String})";
+                            break;
+                    }
+                else
+                    result = $"({printedEnum}) {statement.String}";
                 return true;
             }
 
             return false;
         }
 
-        private string TranslateEnumExpression(Function function,
-            Type desugared, string @params)
+        private string TranslateEnumExpression(Type desugared, string @params)
         {
             if (@params.Contains("::"))
                 return regexDoubleColon.Replace(@params, desugared + ".");

tests/CSharp/CSharp.Tests.cs

@@ -229,6 +229,7 @@ public void TestDefaultArguments()
             methodsWithDefaultValues.DefaultValueType();
             methodsWithDefaultValues.DefaultChar();
             methodsWithDefaultValues.DefaultEmptyChar();
+            methodsWithDefaultValues.DefaultEmptyEnum();
             methodsWithDefaultValues.DefaultRefTypeBeforeOthers();
             methodsWithDefaultValues.DefaultRefTypeAfterOthers();
             methodsWithDefaultValues.DefaultRefTypeBeforeAndAfterOthers(0, null);

tests/CSharp/CSharp.cpp

@@ -584,6 +584,10 @@ void MethodsWithDefaultValues::defaultEmptyChar(char c)
 {
 }
 
+void MethodsWithDefaultValues::defaultEmptyEnum(Empty e)
+{
+}
+
 void MethodsWithDefaultValues::defaultRefTypeBeforeOthers(Foo foo, int i, Bar::Items item)
 {
 }

tests/CSharp/CSharp.h

@@ -379,6 +379,10 @@ class DLL_API DefaultZeroMappedToEnum
     DefaultZeroMappedToEnum(int* = 0);
 };
 
+enum class Empty : unsigned long long int
+{
+};
+
 class DLL_API MethodsWithDefaultValues : public Quux
 {
 public:
@@ -404,6 +408,7 @@ class DLL_API MethodsWithDefaultValues : public Quux
     void defaultValueType(QGenericArgument valueType = QGenericArgument());
     void defaultChar(char c = 'a');
     void defaultEmptyChar(char c = 0);
+    void defaultEmptyEnum(Empty e = Empty(-1));
     void defaultRefTypeBeforeOthers(Foo foo = Foo(), int i = 5, Bar::Items item = Bar::Item2);
     void defaultRefTypeAfterOthers(int i = 5, Bar::Items item = Bar::Item2, Foo foo = Foo());
     void defaultRefTypeBeforeAndAfterOthers(int i = 5, Foo foo = Foo(), Bar::Items item = Bar::Item2, Baz baz = Baz());