Allow method binds to take Object subclasses as arguments

This commit adds a condition to VariantCaster that casts Variants of type OBJECT to any type T, if T is derived from Object.
This change enables a fair bit of code cleanup. First, the Variant implicit cast operators for Node and Control can be removed, which allows for some invalid includes to be removed. Second, helper methods in Tree whose sole purpose was to cast arguments to TreeItem * are no longer necessary.
A few small changes also had to be made to other files, due to the changes cascading down all the includes.

1 files changed, 16 insertions, 0 deletions

diff --git a/tests/core/object/test_method_bind.h b/tests/core/object/test_method_bind.h
index 0c7e47fc89..350a08b6e2 100644
--- a/tests/core/object/test_method_bind.h
+++ b/tests/core/object/test_method_bind.h
@@ -51,9 +51,15 @@ public:
 		TEST_METHODRC,
 		TEST_METHODRC_ARGS,
 		TEST_METHOD_DEFARGS,
+		TEST_METHOD_OBJECT_CAST,
 		TEST_MAX
 	};
 
+	class ObjectSubclass : public Object {
+	public:
+		int value = 1;
+	};
+
 	int test_num = 0;
 
 	bool test_valid[TEST_MAX];
@@ -98,6 +104,10 @@ public:
 		test_valid[TEST_METHOD_DEFARGS] = p_arg1 == 1 && p_arg2 == 2 && p_arg3 == 3 && p_arg4 == 4 && p_arg5 == 5; //temporary
 	}
 
+	void test_method_object_cast(ObjectSubclass *p_object) {
+		test_valid[TEST_METHOD_OBJECT_CAST] = p_object->value == 1;
+	}
+
 	static void _bind_methods() {
 		ClassDB::bind_method(D_METHOD("test_method"), &MethodBindTester::test_method);
 		ClassDB::bind_method(D_METHOD("test_method_args"), &MethodBindTester::test_method_args);
@@ -108,6 +118,7 @@ public:
 		ClassDB::bind_method(D_METHOD("test_methodrc"), &MethodBindTester::test_methodrc);
 		ClassDB::bind_method(D_METHOD("test_methodrc_args"), &MethodBindTester::test_methodrc_args);
 		ClassDB::bind_method(D_METHOD("test_method_default_args"), &MethodBindTester::test_method_default_args, DEFVAL(9) /* wrong on purpose */, DEFVAL(4), DEFVAL(5));
+		ClassDB::bind_method(D_METHOD("test_method_object_cast", "object"), &MethodBindTester::test_method_object_cast);
 	}
 
 	virtual void run_tests() {
@@ -134,6 +145,10 @@ public:
 		test_valid[TEST_METHODRC_ARGS] = int(call("test_methodrc_args", test_num)) == test_num && test_valid[TEST_METHODRC_ARGS];
 
 		call("test_method_default_args", 1, 2, 3, 4);
+
+		ObjectSubclass *obj = memnew(ObjectSubclass);
+		call("test_method_object_cast", obj);
+		memdelete(obj);
 	}
 };
 
@@ -152,6 +167,7 @@ TEST_CASE("[MethodBind] check all method binds") {
 	CHECK(mbt->test_valid[MethodBindTester::TEST_METHODRC]);
 	CHECK(mbt->test_valid[MethodBindTester::TEST_METHODRC_ARGS]);
 	CHECK(mbt->test_valid[MethodBindTester::TEST_METHOD_DEFARGS]);
+	CHECK(mbt->test_valid[MethodBindTester::TEST_METHOD_OBJECT_CAST]);
 
 	memdelete(mbt);
 }