Fix null arguments preventing correct method overload finding

- Fix issue where correct method overload would not be found when using a const `null` as input for a method.
MerlinVR · Nov 28, 2020 · a0c13f3 · a0c13f3
1 parent 2af31ff
commit a0c13f3
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Showing 4 changed files with 26 additions and 13 deletions.
diff --git a/Assets/UdonSharp/Editor/UdonSharpExpressionCapture.cs b/Assets/UdonSharp/Editor/UdonSharpExpressionCapture.cs
@@ -1460,19 +1460,30 @@ private SymbolDefinition HandleGenericUSharpGetComponent(MethodInfo targetMethod
 
         private SymbolDefinition InvokeExtern(SymbolDefinition[] invokeParams)
         {
+            // We use void as a placeholder for a null constant value getting passed in, if null is passed in and the target type is a reference type then we assume they are compatible
+            List<System.Type> typeList = invokeParams.Select(e =>
+            {
+                if (e.declarationType.HasFlag(SymbolDeclTypeFlags.Constant) &&
+                    e.symbolCsType == typeof(object) &&
+                    e.symbolDefaultValue == null)
+                    return typeof(void);
+
+                return e.symbolCsType;
+            }).ToList();
+
             // Find valid overrides
-            MethodBase targetMethod = visitorContext.resolverContext.FindBestOverloadFunction(captureMethods, invokeParams.Select(e => e.symbolCsType).ToList());
+            MethodBase targetMethod = visitorContext.resolverContext.FindBestOverloadFunction(captureMethods, typeList);
 
             if (targetMethod == null)
             {
-                targetMethod = visitorContext.resolverContext.FindBestOverloadFunction(captureMethods, invokeParams.Select(e => e.symbolCsType).ToList(), false);
+                targetMethod = visitorContext.resolverContext.FindBestOverloadFunction(captureMethods, typeList, false);
 
                 if (targetMethod != null &&
                     targetMethod.ReflectedType == typeof(VRC.Udon.UdonBehaviour) &&
                     targetMethod.Name.StartsWith("GetComponent") &&
                     ((MethodInfo)targetMethod).ReturnType.IsGenericParameter)
                 {
-                    // Uhh just skip the else stuff
+                    // Uhh just skip the else stuff, this fixes GetComponent(s) on UdonBehaviour variables.
                 }
                 else
                 {

diff --git a/Assets/UdonSharp/Editor/UdonSharpSymbolTable.cs b/Assets/UdonSharp/Editor/UdonSharpSymbolTable.cs
@@ -14,7 +14,7 @@ public enum SymbolDeclTypeFlags
         Private = 2, // Declared by the user as a private variable on a class
         Local = 4, // Declared by the user as a variable local to a specific scope
         Internal = 8, // Generated as an intermediate variable that stores intermediate calculations
-        Constant = 16, // Used to represent a constant value that does not change. This can either be statically defined constants 
+        Constant = 16, // Used to represent a constant value set by the compiler that does not change after compile time. Variables with const/readonly use the Readonly flag.
         Array = 32, // If this symbol is an array type
         This = 64, // defines one of the 3 builtin `this` assignments for UdonBehaviour, GameObject, and Transform
         Reflection = 128, // Metadata information for type checking and other editor time info

diff --git a/Assets/UdonSharp/Editor/UdonSharpUtils.cs b/Assets/UdonSharp/Editor/UdonSharpUtils.cs
@@ -201,6 +201,10 @@ public static bool IsImplicitlyAssignableFrom(this System.Type targetType, Syste
             if (IsNumericImplicitCastValid(targetType, assignee))
                 return true;
 
+            // We use void as a placeholder for a null constant value getting passed in, if null is passed in and the target type is a reference type then we assume they are compatible
+            if (assignee == typeof(void) && !targetType.IsValueType)
+                return true;
+
             // Handle user-defined implicit conversion operators defined on both sides
             // Roughly follows https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/language-specification/conversions#processing-of-user-defined-implicit-conversions
 

diff --git a/Assets/UdonSharp/Tests/TestScripts/Core/MethodCallsTest.cs b/Assets/UdonSharp/Tests/TestScripts/Core/MethodCallsTest.cs
@@ -91,16 +91,14 @@ public void ExecuteTests()
             RigidbodyConstraints constraints = (RigidbodyConstraints)126;
 
             tester.TestAssertion("Enum cast", constraints == RigidbodyConstraints.FreezeAll);
-        }
 
-        //public void test(int a, bool b, float c = 5f, params float[] d)
-        //{
-        //    test(a, b);
-        //}
+            Transform currentParent = transform.parent;
+
+            transform.SetParent(null);
 
-        //public void test2(params object[] strings)
-        //{
-        //    test2(new string[] { "aa", "bbb" });
-        //}
+            tester.TestAssertion("Transform detach parent (null parameter method finding)", transform.parent == null);
+
+            transform.SetParent(currentParent);
+        }
     }
 }