Fixed a bug when a char parameter is assigned a default value of 0.

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

src/Generator/Passes/HandleDefaultParamValuesPass.cs

@@ -44,6 +44,8 @@ namespace CppSharp.Passes
                     continue;
 
                 CheckForULongValue(parameter, desugared);
+
+                CheckForDefaultEmptyChar(parameter, desugared);
             }
 
             GenerateOverloads(function, overloadIndices);
@@ -146,6 +148,15 @@ namespace CppSharp.Passes
                 parameter.DefaultArgument.String = value.ToString(CultureInfo.InvariantCulture);
         }
 
+        private void CheckForDefaultEmptyChar(Parameter parameter, Type desugared)
+        {
+            if (parameter.DefaultArgument.String == "0" && Driver.Options.MarshalCharAsManagedChar &&
+                desugared.IsPrimitiveType(PrimitiveType.Char))
+            {
+                parameter.DefaultArgument.String = "'\\0'";
+            }
+        }
+
         private static void GenerateOverloads(Function function, List<int> overloadIndices)
         {
             foreach (var overloadIndex in overloadIndices)

tests/CSharpTemp/CSharpTemp.Tests.cs

@@ -131,6 +131,7 @@ public class CSharpTempTests : GeneratorTestFixture
     {
         var methodsWithDefaultValues = new MethodsWithDefaultValues();
         methodsWithDefaultValues.DefaultChar();
+        methodsWithDefaultValues.DefaultEmptyChar();
         methodsWithDefaultValues.DefaultPointer();
         methodsWithDefaultValues.DefaultRefTypeAfterOthers();
         methodsWithDefaultValues.DefaultRefTypeBeforeAndAfterOthers(5, new Foo());

tests/CSharpTemp/CSharpTemp.cpp

@@ -249,6 +249,10 @@ void MethodsWithDefaultValues::defaultChar(char c)
 {
 }
 
+void MethodsWithDefaultValues::defaultEmptyChar(char c)
+{
+}
+
 void MethodsWithDefaultValues::defaultRefTypeBeforeOthers(Foo foo, int i, Bar::Items item)
 {
 }

tests/CSharpTemp/CSharpTemp.h

@@ -219,6 +219,7 @@ public:
     void defaultPointer(Foo* ptr = 0);
     void defaultValueType(ValueType bar = ValueType());
     void defaultChar(char c = 'a');
+    void defaultEmptyChar(char c = 0);
     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());