Fix enums precedence in MethodBinder

Author: jhonabreul

src/embed_tests/TestMethodBinder.cs

@@ -95,6 +95,7 @@ public void SetUp()
             CSharpModel.LastDelegateCalled = null;
             CSharpModel.LastFuncCalled = null;
             CSharpModel.MethodCalled = null;
+            CSharpModel.ProvidedArgument = null;
         }
 
         [Test]
@@ -1360,6 +1361,47 @@ def call_method_with_action3():
             Assert.AreEqual(expectedInnerMethodCalled, CSharpModel.LastFuncCalled);
         }
 
+        [Test]
+        public void NumericArgumentsTakePrecedenceOverEnums()
+        {
+            using var _ = Py.GIL();
+
+            var module = PyModule.FromString("NumericArgumentsTakePrecedenceOverEnums", @$"
+from clr import AddReference
+AddReference(""System"")
+from Python.EmbeddingTest import *
+from System import DayOfWeek
+
+def call_method_with_int():
+    TestMethodBinder.CSharpModel().NumericalArgumentMethod(1)
+
+def call_method_with_float():
+    TestMethodBinder.CSharpModel().NumericalArgumentMethod(0.1)
+
+def call_method_with_numpy_float():
+    TestMethodBinder.CSharpModel().NumericalArgumentMethod(TestMethodBinder.Numpy.float64(0.1))
+
+def call_method_with_enum():
+    TestMethodBinder.CSharpModel().NumericalArgumentMethod(DayOfWeek.MONDAY)
+");
+
+            module.GetAttr("call_method_with_int").Invoke();
+            Assert.AreEqual(typeof(int), CSharpModel.ProvidedArgument.GetType());
+            Assert.AreEqual(1, CSharpModel.ProvidedArgument);
+
+            module.GetAttr("call_method_with_float").Invoke();
+            Assert.AreEqual(typeof(double), CSharpModel.ProvidedArgument.GetType());
+            Assert.AreEqual(0.1d, CSharpModel.ProvidedArgument);
+
+            module.GetAttr("call_method_with_numpy_float").Invoke();
+            Assert.AreEqual(typeof(decimal), CSharpModel.ProvidedArgument.GetType());
+            Assert.AreEqual(0.1m, CSharpModel.ProvidedArgument);
+
+            module.GetAttr("call_method_with_enum").Invoke();
+            Assert.AreEqual(typeof(DayOfWeek), CSharpModel.ProvidedArgument.GetType());
+            Assert.AreEqual(DayOfWeek.Monday, CSharpModel.ProvidedArgument);
+        }
+
         // Used to test that we match this function with Py DateTime & Date Objects
         public static int GetMonth(DateTime test)
         {
@@ -1442,6 +1484,10 @@ public void NumericalArgumentMethod(decimal value)
             {
                 ProvidedArgument = value;
             }
+            public void NumericalArgumentMethod(DayOfWeek value)
+            {
+                ProvidedArgument = value;
+            }
             public void EnumerableKeyValuePair(IEnumerable<KeyValuePair<string, decimal>> value)
             {
                 ProvidedArgument = value;

src/runtime/MethodBinder.cs

@@ -389,14 +389,24 @@ internal static int ArgPrecedence(Type t, bool isOperatorMethod)
                 return ArgPrecedence(Nullable.GetUnderlyingType(t), isOperatorMethod);
             }
 
+            // Enums precedence is higher tan PyObject but lower than numbers.
+            // PyObject precedence is higher and objects.
+            // Strings precedence is higher than objects.
+            // So we have:
+            //  - String: 50
+            //  - Object: 40
+            //  - PyObject: 39
+            //  - Enum: 38
+            //  - Numbers: 2 -> 29
+
             if (t.IsEnum)
             {
-                return -2;
+                return 38;
             }
 
             if (t.IsAssignableFrom(typeof(PyObject)) && !isOperatorMethod)
             {
-                return -1;
+                return 39;
             }
 
             if (t.IsArray)
@@ -414,7 +424,7 @@ internal static int ArgPrecedence(Type t, bool isOperatorMethod)
             switch (tc)
             {
                 case TypeCode.Object:
-                    return 1;
+                    return 40;
 
                 // we place higher precision methods at the top
                 case TypeCode.Decimal:
@@ -444,10 +454,10 @@ internal static int ArgPrecedence(Type t, bool isOperatorMethod)
                     return 29;
 
                 case TypeCode.String:
-                    return 30;
+                    return 50;
 
                 case TypeCode.Boolean:
-                    return 40;
+                    return 60;
             }
 
             return 2000;