Merge pull request #38723 from neikeq/initial-classdb-test

Added tests for ClassDB

main/tests/test_class_db.cpp

@@ -0,0 +1,882 @@
+/*************************************************************************/
+/*  test_class_db.cpp                                                    */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "test_class_db.h"
+
+#include "core/global_constants.h"
+#include "core/ordered_hash_map.h"
+#include "core/os/os.h"
+#include "core/string_name.h"
+#include "core/ustring.h"
+#include "core/variant.h"
+
+namespace TestClassDB {
+
+enum class [[nodiscard]] TestResult{
+	FAILED,
+	PASS
+};
+
+#define TEST_FAIL_COND_FATAL(m_cond, m_msg) \
+	if (unlikely(m_cond)) {                 \
+		ERR_PRINT(m_msg);                   \
+		return TestResult::FAILED;          \
+	} else                                  \
+		((void)0)
+
+#define TEST_FAIL_COND(m_cond, m_msg)         \
+	if (unlikely(m_cond)) {                   \
+		ERR_PRINT(m_msg);                     \
+		__test_result__ = TestResult::FAILED; \
+	} else                                    \
+		((void)0)
+
+#define TEST_CHECK_FATAL(m_test_expr)                    \
+	if (unlikely((m_test_expr) == TestResult::FAILED)) { \
+		return TestResult::FAILED;                       \
+	} else                                               \
+		((void)0)
+
+#define TEST_CHECK(m_test_expr)                          \
+	if (unlikely((m_test_expr) == TestResult::FAILED)) { \
+		__test_result__ = TestResult::FAILED;            \
+	} else                                               \
+		((void)0)
+
+#define TEST_START()                               \
+	TestResult __test_result__ = TestResult::PASS; \
+	((void)0)
+
+#define TEST_END() return __test_result__;
+
+struct TypeReference {
+	StringName name;
+	bool is_enum = false;
+};
+
+struct ConstantData {
+	String name;
+	int value = 0;
+};
+
+struct EnumData {
+	StringName name;
+	List<ConstantData> constants;
+
+	_FORCE_INLINE_ bool operator==(const EnumData &p_enum) const {
+		return p_enum.name == name;
+	}
+};
+
+struct PropertyData {
+	StringName name;
+	int index = 0;
+
+	StringName getter;
+	StringName setter;
+};
+
+struct ArgumentData {
+	TypeReference type;
+	String name;
+	bool has_defval = false;
+	Variant defval;
+};
+
+struct MethodData {
+	StringName name;
+	TypeReference return_type;
+	List<ArgumentData> arguments;
+	bool is_virtual = false;
+	bool is_vararg = false;
+};
+
+struct SignalData {
+	StringName name;
+	List<ArgumentData> arguments;
+};
+
+struct ExposedClass {
+	StringName name;
+	StringName base;
+
+	bool is_singleton = false;
+	bool is_instantiable = false;
+	bool is_reference = false;
+
+	ClassDB::APIType api_type;
+
+	List<ConstantData> constants;
+	List<EnumData> enums;
+	List<PropertyData> properties;
+	List<MethodData> methods;
+	List<SignalData> signals_;
+
+	const PropertyData *find_property_by_name(const StringName &p_name) const {
+		for (const List<PropertyData>::Element *E = properties.front(); E; E = E->next()) {
+			if (E->get().name == p_name) {
+				return &E->get();
+			}
+		}
+
+		return nullptr;
+	}
+
+	const MethodData *find_method_by_name(const StringName &p_name) const {
+		for (const List<MethodData>::Element *E = methods.front(); E; E = E->next()) {
+			if (E->get().name == p_name) {
+				return &E->get();
+			}
+		}
+
+		return nullptr;
+	}
+};
+
+struct NamesCache {
+	StringName variant_type = StaticCString::create("Variant");
+	StringName object_class = StaticCString::create("Object");
+	StringName reference_class = StaticCString::create("Reference");
+	StringName string_type = StaticCString::create("String");
+	StringName string_name_type = StaticCString::create("StringName");
+	StringName node_path_type = StaticCString::create("NodePath");
+	StringName bool_type = StaticCString::create("bool");
+	StringName int_type = StaticCString::create("int");
+	StringName float_type = StaticCString::create("float");
+	StringName void_type = StaticCString::create("void");
+	StringName vararg_stub_type = StaticCString::create("@VarArg@");
+	StringName vector2_type = StaticCString::create("Vector2");
+	StringName rect2_type = StaticCString::create("Rect2");
+	StringName vector3_type = StaticCString::create("Vector3");
+
+	// Object not included as it must be checked for all derived classes
+	static constexpr int nullable_types_count = 17;
+	StringName nullable_types[nullable_types_count] = {
+		string_type,
+		string_name_type,
+		node_path_type,
+
+		StaticCString::create(_STR(Array)),
+		StaticCString::create(_STR(Dictionary)),
+		StaticCString::create(_STR(Callable)),
+		StaticCString::create(_STR(Signal)),
+
+		StaticCString::create(_STR(PackedByteArray)),
+		StaticCString::create(_STR(PackedInt32Array)),
+		StaticCString::create(_STR(PackedInt64rray)),
+		StaticCString::create(_STR(PackedFloat32Array)),
+		StaticCString::create(_STR(PackedFloat64Array)),
+		StaticCString::create(_STR(PackedStringArray)),
+		StaticCString::create(_STR(PackedVector2Array)),
+		StaticCString::create(_STR(PackedVector3Array)),
+		StaticCString::create(_STR(PackedColorArray)),
+	};
+
+	bool is_nullable_type(const StringName &p_type) const {
+		for (int i = 0; i < nullable_types_count; i++) {
+			if (p_type == nullable_types[i]) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+};
+
+typedef OrderedHashMap<StringName, ExposedClass> ExposedClasses;
+
+struct Context {
+	Vector<StringName> enum_types;
+	Vector<StringName> builtin_types;
+	ExposedClasses exposed_classes;
+	List<EnumData> global_enums;
+	NamesCache names_cache;
+
+	const ExposedClass *find_exposed_class(const StringName &p_name) const {
+		ExposedClasses::ConstElement elem = exposed_classes.find(p_name);
+		return elem ? &elem.value() : nullptr;
+	}
+
+	const ExposedClass *find_exposed_class(const TypeReference &p_type_ref) const {
+		ExposedClasses::ConstElement elem = exposed_classes.find(p_type_ref.name);
+		return elem ? &elem.value() : nullptr;
+	}
+
+	bool has_type(const Context &p_context, const TypeReference &p_type_ref) const {
+		if (p_context.builtin_types.find(p_type_ref.name) >= 0) {
+			return true;
+		}
+
+		if (p_type_ref.is_enum) {
+			if (p_context.enum_types.find(p_type_ref.name) >= 0) {
+				return true;
+			}
+
+			// Enum not found. Most likely because none of its constants were bound, so it's empty. That's fine. Use int instead.
+			return p_context.builtin_types.find(p_context.names_cache.int_type);
+		}
+
+		return false;
+	}
+};
+
+bool arg_default_value_is_assignable_to_type(const Context &p_context, const Variant &p_val, const TypeReference &p_arg_type) {
+	if (p_arg_type.name == p_context.names_cache.variant_type) {
+		// Variant can take anything
+		return true;
+	}
+
+	switch (p_val.get_type()) {
+		case Variant::NIL:
+			return p_context.find_exposed_class(p_arg_type) ||
+				   p_context.names_cache.is_nullable_type(p_arg_type.name);
+		case Variant::BOOL:
+			return p_arg_type.name == p_context.names_cache.bool_type;
+		case Variant::INT:
+			return p_arg_type.name == p_context.names_cache.int_type ||
+				   p_arg_type.name == p_context.names_cache.float_type ||
+				   p_arg_type.is_enum;
+		case Variant::FLOAT:
+			return p_arg_type.name == p_context.names_cache.float_type;
+		case Variant::STRING:
+		case Variant::STRING_NAME:
+			return p_arg_type.name == p_context.names_cache.string_type ||
+				   p_arg_type.name == p_context.names_cache.string_name_type ||
+				   p_arg_type.name == p_context.names_cache.node_path_type;
+		case Variant::NODE_PATH:
+			return p_arg_type.name == p_context.names_cache.node_path_type;
+		case Variant::TRANSFORM:
+		case Variant::TRANSFORM2D:
+		case Variant::BASIS:
+		case Variant::QUAT:
+		case Variant::PLANE:
+		case Variant::AABB:
+		case Variant::COLOR:
+		case Variant::VECTOR2:
+		case Variant::RECT2:
+		case Variant::VECTOR3:
+		case Variant::_RID:
+		case Variant::ARRAY:
+		case Variant::DICTIONARY:
+		case Variant::PACKED_BYTE_ARRAY:
+		case Variant::PACKED_INT32_ARRAY:
+		case Variant::PACKED_INT64_ARRAY:
+		case Variant::PACKED_FLOAT32_ARRAY:
+		case Variant::PACKED_FLOAT64_ARRAY:
+		case Variant::PACKED_STRING_ARRAY:
+		case Variant::PACKED_VECTOR2_ARRAY:
+		case Variant::PACKED_VECTOR3_ARRAY:
+		case Variant::PACKED_COLOR_ARRAY:
+		case Variant::CALLABLE:
+		case Variant::SIGNAL:
+			return p_arg_type.name == Variant::get_type_name(p_val.get_type());
+		case Variant::OBJECT:
+			return p_context.find_exposed_class(p_arg_type);
+		case Variant::VECTOR2I:
+			return p_arg_type.name == p_context.names_cache.vector2_type ||
+				   p_arg_type.name == Variant::get_type_name(p_val.get_type());
+		case Variant::RECT2I:
+			return p_arg_type.name == p_context.names_cache.rect2_type ||
+				   p_arg_type.name == Variant::get_type_name(p_val.get_type());
+		case Variant::VECTOR3I:
+			return p_arg_type.name == p_context.names_cache.vector3_type ||
+				   p_arg_type.name == Variant::get_type_name(p_val.get_type());
+		default:
+			ERR_PRINT("Unexpected Variant type: " + itos(p_val.get_type()));
+			break;
+	}
+
+	return false;
+}
+
+TestResult validate_property(const Context &p_context, const ExposedClass &p_class, const PropertyData &p_prop) {
+	TEST_START();
+
+	const MethodData *setter = p_class.find_method_by_name(p_prop.setter);
+
+	// Search it in base classes too
+	const ExposedClass *top = &p_class;
+	while (!setter && top->base != StringName()) {
+		top = p_context.find_exposed_class(top->base);
+		TEST_FAIL_COND(!top, "Class not found '" + top->base + "'. Inherited by '" + top->name + "'.");
+		setter = top->find_method_by_name(p_prop.setter);
+	}
+
+	const MethodData *getter = p_class.find_method_by_name(p_prop.getter);
+
+	// Search it in base classes too
+	top = &p_class;
+	while (!getter && top->base != StringName()) {
+		top = p_context.find_exposed_class(top->base);
+		TEST_FAIL_COND(!top, "Class not found '" + top->base + "'. Inherited by '" + top->name + "'.");
+		getter = top->find_method_by_name(p_prop.getter);
+	}
+
+	TEST_FAIL_COND(!setter && !getter,
+			"Couldn't find neither the setter nor the getter for property: '" + p_class.name + "." + String(p_prop.name) + "'.");
+
+	if (setter) {
+		int setter_argc = p_prop.index != -1 ? 2 : 1;
+		TEST_FAIL_COND(setter->arguments.size() != setter_argc,
+				"Invalid property setter argument count: '" + p_class.name + "." + String(p_prop.name) + "'.");
+	}
+
+	if (getter) {
+		int getter_argc = p_prop.index != -1 ? 1 : 0;
+		TEST_FAIL_COND(getter->arguments.size() != getter_argc,
+				"Invalid property setter argument count: '" + p_class.name + "." + String(p_prop.name) + "'.");
+	}
+
+	if (getter && setter) {
+		const ArgumentData &setter_first_arg = setter->arguments.back()->get();
+		if (getter->return_type.name != setter_first_arg.type.name) {
+			// Special case for Node::set_name
+			bool whitelisted = getter->return_type.name == p_context.names_cache.string_name_type &&
+							   setter_first_arg.type.name == p_context.names_cache.string_type;
+
+			TEST_FAIL_COND(!whitelisted,
+					"Return type from getter doesn't match first argument of setter, for property: '" + p_class.name + "." + String(p_prop.name) + "'.");
+		}
+	}
+
+	const TypeReference &prop_type_ref = getter ? getter->return_type : setter->arguments.back()->get().type;
+
+	const ExposedClass *prop_class = p_context.find_exposed_class(prop_type_ref);
+	if (prop_class) {
+		TEST_FAIL_COND(prop_class->is_singleton,
+				"Property type is a singleton: '" + p_class.name + "." + String(p_prop.name) + "'.");
+	} else {
+		TEST_FAIL_COND(!p_context.has_type(p_context, prop_type_ref),
+				"Property type '" + prop_type_ref.name + "' not found: '" + p_class.name + "." + String(p_prop.name) + "'.");
+	}
+
+	if (getter) {
+		if (p_prop.index != -1) {
+			const ArgumentData &idx_arg = getter->arguments.front()->get();
+			if (idx_arg.type.name != p_context.names_cache.int_type) {
+				// If not an int, it can be an enum
+				TEST_FAIL_COND(p_context.enum_types.find(idx_arg.type.name) < 0,
+						"Invalid type '" + idx_arg.type.name + "' for index argument of property getter: '" + p_class.name + "." + String(p_prop.name) + "'.");
+			}
+		}
+	}
+
+	if (setter) {
+		if (p_prop.index != -1) {
+			const ArgumentData &idx_arg = setter->arguments.front()->get();
+			if (idx_arg.type.name != p_context.names_cache.int_type) {
+				// Assume the index parameter is an enum
+				// If not an int, it can be an enum
+				TEST_FAIL_COND(p_context.enum_types.find(idx_arg.type.name) < 0,
+						"Invalid type '" + idx_arg.type.name + "' for index argument of property setter: '" + p_class.name + "." + String(p_prop.name) + "'.");
+			}
+		}
+	}
+
+	TEST_END();
+}
+
+TestResult validate_method(const Context &p_context, const ExposedClass &p_class, const MethodData &p_method) {
+	TEST_START();
+
+	const ExposedClass *return_class = p_context.find_exposed_class(p_method.return_type);
+	if (return_class) {
+		TEST_FAIL_COND(return_class->is_singleton,
+				"Method return type is a singleton: '" + p_class.name + "." + p_method.name + "'.");
+	}
+
+	for (const List<ArgumentData>::Element *F = p_method.arguments.front(); F; F = F->next()) {
+		const ArgumentData &arg = F->get();
+
+		const ExposedClass *arg_class = p_context.find_exposed_class(arg.type);
+		if (arg_class) {
+			TEST_FAIL_COND(arg_class->is_singleton,
+					"Argument type is a singleton: '" + arg.name + "' of method '" + p_class.name + "." + p_method.name + "'.");
+		} else {
+			TEST_FAIL_COND(!p_context.has_type(p_context, arg.type),
+					"Argument type '" + arg.type.name + "' not found: '" + arg.name + "' of method" + p_class.name + "." + p_method.name + "'.");
+		}
+
+		if (arg.has_defval) {
+			TEST_FAIL_COND(!arg_default_value_is_assignable_to_type(p_context, arg.defval, arg.type),
+					"Invalid default value for parameter '" + arg.name + "' of method '" + p_class.name + "." + p_method.name + "'.");
+		}
+	}
+
+	TEST_END();
+}
+
+TestResult validate_signal(const Context &p_context, const ExposedClass &p_class, const SignalData &p_signal) {
+	TEST_START();
+
+	for (const List<ArgumentData>::Element *F = p_signal.arguments.front(); F; F = F->next()) {
+		const ArgumentData &arg = F->get();
+
+		const ExposedClass *arg_class = p_context.find_exposed_class(arg.type);
+		if (arg_class) {
+			TEST_FAIL_COND(arg_class->is_singleton,
+					"Argument class is a singleton: '" + arg.name + "' of signal" + p_class.name + "." + p_signal.name + "'.");
+		} else {
+			TEST_FAIL_COND(!p_context.has_type(p_context, arg.type),
+					"Argument type '" + arg.type.name + "' not found: '" + arg.name + "' of signal" + p_class.name + "." + p_signal.name + "'.");
+		}
+	}
+
+	TEST_END();
+}
+
+TestResult validate_class(const Context &p_context, const ExposedClass &p_exposed_class) {
+	TEST_START();
+
+	bool is_derived_type = p_exposed_class.base != StringName();
+
+	if (!is_derived_type) {
+		// Asserts about the base Object class
+		TEST_FAIL_COND_FATAL(p_exposed_class.name != p_context.names_cache.object_class,
+				"Class '" + p_exposed_class.name + "' has no base class.");
+		TEST_FAIL_COND_FATAL(!p_exposed_class.is_instantiable,
+				"Object class is not instantiable.");
+		TEST_FAIL_COND_FATAL(p_exposed_class.api_type != ClassDB::API_CORE,
+				"Object class is API is not API_CORE.");
+		TEST_FAIL_COND_FATAL(p_exposed_class.is_singleton,
+				"Object class is registered as a singleton.");
+	}
+
+	CRASH_COND_MSG(p_exposed_class.is_singleton && p_exposed_class.base != p_context.names_cache.object_class,
+			"Singleton base class '" + String(p_exposed_class.base) + "' is not Object, for class '" + p_exposed_class.name + "'.");
+
+	CRASH_COND_MSG(is_derived_type && !p_context.exposed_classes.has(p_exposed_class.base),
+			"Base type '" + p_exposed_class.base.operator String() + "' does not exist, for class '" + p_exposed_class.name + "'.");
+
+	for (const List<PropertyData>::Element *F = p_exposed_class.properties.front(); F; F = F->next()) {
+		TEST_CHECK(validate_property(p_context, p_exposed_class, F->get()));
+	}
+
+	for (const List<MethodData>::Element *F = p_exposed_class.methods.front(); F; F = F->next()) {
+		TEST_CHECK(validate_method(p_context, p_exposed_class, F->get()));
+	}
+
+	for (const List<SignalData>::Element *F = p_exposed_class.signals_.front(); F; F = F->next()) {
+		TEST_CHECK(validate_signal(p_context, p_exposed_class, F->get()));
+	}
+
+	TEST_END();
+}
+
+TestResult add_exposed_classes(Context &r_context) {
+	TEST_START();
+
+	List<StringName> class_list;
+	ClassDB::get_class_list(&class_list);
+	class_list.sort_custom<StringName::AlphCompare>();
+
+	while (class_list.size()) {
+		StringName class_name = class_list.front()->get();
+
+		ClassDB::APIType api_type = ClassDB::get_api_type(class_name);
+
+		if (api_type == ClassDB::API_NONE) {
+			class_list.pop_front();
+			continue;
+		}
+
+		if (!ClassDB::is_class_exposed(class_name)) {
+			OS::get_singleton()->print("Ignoring class '%s' because it's not exposed\n", String(class_name).utf8().get_data());
+			class_list.pop_front();
+			continue;
+		}
+
+		if (!ClassDB::is_class_enabled(class_name)) {
+			OS::get_singleton()->print("Ignoring class '%s' because it's not enabled\n", String(class_name).utf8().get_data());
+			class_list.pop_front();
+			continue;
+		}
+
+		ClassDB::ClassInfo *class_info = ClassDB::classes.getptr(class_name);
+
+		ExposedClass exposed_class;
+		exposed_class.name = class_name;
+		exposed_class.api_type = api_type;
+		exposed_class.is_singleton = Engine::get_singleton()->has_singleton(class_name);
+		exposed_class.is_instantiable = class_info->creation_func && !exposed_class.is_singleton;
+		exposed_class.is_reference = ClassDB::is_parent_class(class_name, "Reference");
+		exposed_class.base = ClassDB::get_parent_class(class_name);
+
+		// Add properties
+
+		List<PropertyInfo> property_list;
+		ClassDB::get_property_list(class_name, &property_list, true);
+
+		Map<StringName, StringName> accessor_methods;
+
+		for (const List<PropertyInfo>::Element *E = property_list.front(); E; E = E->next()) {
+			const PropertyInfo &property = E->get();
+
+			if (property.usage & PROPERTY_USAGE_GROUP || property.usage & PROPERTY_USAGE_SUBGROUP || property.usage & PROPERTY_USAGE_CATEGORY) {
+				continue;
+			}
+
+			PropertyData prop;
+			prop.name = property.name;
+			prop.setter = ClassDB::get_property_setter(class_name, prop.name);
+			prop.getter = ClassDB::get_property_getter(class_name, prop.name);
+
+			if (prop.setter != StringName()) {
+				accessor_methods[prop.setter] = prop.name;
+			}
+			if (prop.getter != StringName()) {
+				accessor_methods[prop.getter] = prop.name;
+			}
+
+			bool valid = false;
+			prop.index = ClassDB::get_property_index(class_name, prop.name, &valid);
+			TEST_FAIL_COND(!valid, "Invalid property: '" + exposed_class.name + "." + String(prop.name) + "'.");
+
+			exposed_class.properties.push_back(prop);
+		}
+
+		// Add methods
+
+		List<MethodInfo> virtual_method_list;
+		ClassDB::get_virtual_methods(class_name, &virtual_method_list, true);
+
+		List<MethodInfo> method_list;
+		ClassDB::get_method_list(class_name, &method_list, true);
+		method_list.sort();
+
+		for (List<MethodInfo>::Element *E = method_list.front(); E; E = E->next()) {
+			const MethodInfo &method_info = E->get();
+
+			int argc = method_info.arguments.size();
+
+			if (method_info.name.empty()) {
+				continue;
+			}
+
+			MethodData method;
+			method.name = method_info.name;
+
+			if (method_info.flags & METHOD_FLAG_VIRTUAL) {
+				method.is_virtual = true;
+			}
+
+			PropertyInfo return_info = method_info.return_val;
+
+			MethodBind *m = method.is_virtual ? nullptr : ClassDB::get_method(class_name, method_info.name);
+
+			method.is_vararg = m && m->is_vararg();
+
+			if (!m && !method.is_virtual) {
+				TEST_FAIL_COND(!virtual_method_list.find(method_info),
+						"Missing MethodBind for non-virtual method: '" + exposed_class.name + "." + method.name + "'.");
+
+				// A virtual method without the virtual flag. This is a special case.
+
+				// The method Object.free is registered as a virtual method, but without the virtual flag.
+				// This is because this method is not supposed to be overridden, but called.
+				// We assume the return type is void.
+				method.return_type.name = r_context.names_cache.void_type;
+
+				// Actually, more methods like this may be added in the future, which could return
+				// something different. Let's put this check to notify us if that ever happens.
+				if (exposed_class.name != r_context.names_cache.object_class || String(method.name) != "free") {
+					WARN_PRINT("Notification: New unexpected virtual non-overridable method found."
+							   " We only expected Object.free, but found '" +
+							   exposed_class.name + "." + method.name + "'.");
+				}
+			} else if (return_info.type == Variant::INT && return_info.usage & PROPERTY_USAGE_CLASS_IS_ENUM) {
+				method.return_type.name = return_info.class_name;
+				method.return_type.is_enum = true;
+			} else if (return_info.class_name != StringName()) {
+				method.return_type.name = return_info.class_name;
+
+				bool bad_reference_hint = !method.is_virtual && return_info.hint != PROPERTY_HINT_RESOURCE_TYPE &&
+										  ClassDB::is_parent_class(return_info.class_name, r_context.names_cache.reference_class);
+				TEST_FAIL_COND(bad_reference_hint, String() + "Return type is reference but hint is not '" _STR(PROPERTY_HINT_RESOURCE_TYPE) "'." +
+														   " Are you returning a reference type by pointer? Method: '" +
+														   exposed_class.name + "." + method.name + "'.");
+			} else if (return_info.hint == PROPERTY_HINT_RESOURCE_TYPE) {
+				method.return_type.name = return_info.hint_string;
+			} else if (return_info.type == Variant::NIL && return_info.usage & PROPERTY_USAGE_NIL_IS_VARIANT) {
+				method.return_type.name = r_context.names_cache.variant_type;
+			} else if (return_info.type == Variant::NIL) {
+				method.return_type.name = r_context.names_cache.void_type;
+			} else {
+				// NOTE: We don't care about the size and sign of int and float in these tests
+				method.return_type.name = Variant::get_type_name(return_info.type);
+			}
+
+			for (int i = 0; i < argc; i++) {
+				PropertyInfo arg_info = method_info.arguments[i];
+
+				String orig_arg_name = arg_info.name;
+
+				ArgumentData arg;
+				arg.name = orig_arg_name;
+
+				if (arg_info.type == Variant::INT && arg_info.usage & PROPERTY_USAGE_CLASS_IS_ENUM) {
+					arg.type.name = arg_info.class_name;
+					arg.type.is_enum = true;
+				} else if (arg_info.class_name != StringName()) {
+					arg.type.name = arg_info.class_name;
+				} else if (arg_info.hint == PROPERTY_HINT_RESOURCE_TYPE) {
+					arg.type.name = arg_info.hint_string;
+				} else if (arg_info.type == Variant::NIL) {
+					arg.type.name = r_context.names_cache.variant_type;
+				} else {
+					// NOTE: We don't care about the size and sign of int and float in these tests
+					arg.type.name = Variant::get_type_name(arg_info.type);
+				}
+
+				if (m && m->has_default_argument(i)) {
+					arg.has_defval = true;
+					arg.defval = m->get_default_argument(i);
+				}
+
+				method.arguments.push_back(arg);
+			}
+
+			if (method.is_vararg) {
+				ArgumentData vararg;
+				vararg.type.name = r_context.names_cache.vararg_stub_type;
+				vararg.name = "@varargs@";
+				method.arguments.push_back(vararg);
+			}
+
+			TEST_FAIL_COND(exposed_class.find_property_by_name(method.name),
+					"Method name conflicts with property: '" + String(class_name) + "." + String(method.name) + "'.");
+
+			// Classes starting with an underscore are ignored unless they're used as a property setter or getter
+			if (!method.is_virtual && String(method.name)[0] == '_') {
+				for (const List<PropertyData>::Element *F = exposed_class.properties.front(); F; F = F->next()) {
+					const PropertyData &prop = F->get();
+
+					if (prop.setter == method.name || prop.getter == method.name) {
+						exposed_class.methods.push_back(method);
+						break;
+					}
+				}
+			} else {
+				exposed_class.methods.push_back(method);
+			}
+		}
+
+		// Add signals
+
+		const HashMap<StringName, MethodInfo> &signal_map = class_info->signal_map;
+		const StringName *k = nullptr;
+
+		while ((k = signal_map.next(k))) {
+			SignalData signal;
+
+			const MethodInfo &method_info = signal_map.get(*k);
+
+			signal.name = method_info.name;
+
+			int argc = method_info.arguments.size();
+
+			for (int i = 0; i < argc; i++) {
+				PropertyInfo arg_info = method_info.arguments[i];
+
+				String orig_arg_name = arg_info.name;
+
+				ArgumentData arg;
+				arg.name = orig_arg_name;
+
+				if (arg_info.type == Variant::INT && arg_info.usage & PROPERTY_USAGE_CLASS_IS_ENUM) {
+					arg.type.name = arg_info.class_name;
+					arg.type.is_enum = true;
+				} else if (arg_info.class_name != StringName()) {
+					arg.type.name = arg_info.class_name;
+				} else if (arg_info.hint == PROPERTY_HINT_RESOURCE_TYPE) {
+					arg.type.name = arg_info.hint_string;
+				} else if (arg_info.type == Variant::NIL) {
+					arg.type.name = r_context.names_cache.variant_type;
+				} else {
+					// NOTE: We don't care about the size and sign of int and float in these tests
+					arg.type.name = Variant::get_type_name(arg_info.type);
+				}
+
+				signal.arguments.push_back(arg);
+			}
+
+			bool method_conflict = exposed_class.find_property_by_name(signal.name);
+
+			if (method_conflict || exposed_class.find_method_by_name(signal.name)) {
+				// TODO:
+				// ClassDB allows signal names that conflict with method or property names.
+				// However registering a signal with a conflicting name is still considered wrong.
+				// Unfortunately there are some existing cases that are yet to be fixed.
+				// Until those are fixed we will print a warning instead of failing the test.
+				WARN_PRINT("Signal name conflicts with " + String(method_conflict ? "method" : "property") +
+						   ": '" + String(class_name) + "." + String(signal.name) + "'.");
+			}
+
+			exposed_class.signals_.push_back(signal);
+		}
+
+		// Add enums and constants
+
+		List<String> constants;
+		ClassDB::get_integer_constant_list(class_name, &constants, true);
+
+		const HashMap<StringName, List<StringName>> &enum_map = class_info->enum_map;
+		k = nullptr;
+
+		while ((k = enum_map.next(k))) {
+			EnumData enum_;
+			enum_.name = *k;
+
+			const List<StringName> &enum_constants = enum_map.get(*k);
+			for (const List<StringName>::Element *E = enum_constants.front(); E; E = E->next()) {
+				const StringName &constant_name = E->get();
+				int *value = class_info->constant_map.getptr(constant_name);
+				TEST_FAIL_COND(!value, "Missing enum constant value: '" +
+											   String(class_name) + "." + String(enum_.name) + "." + String(constant_name) + "'.");
+				constants.erase(constant_name);
+
+				ConstantData constant;
+				constant.name = constant_name;
+				constant.value = *value;
+
+				enum_.constants.push_back(constant);
+			}
+
+			exposed_class.enums.push_back(enum_);
+
+			r_context.enum_types.push_back(String(class_name) + "." + String(*k));
+		}
+
+		for (const List<String>::Element *E = constants.front(); E; E = E->next()) {
+			const String &constant_name = E->get();
+			int *value = class_info->constant_map.getptr(StringName(E->get()));
+			TEST_FAIL_COND(!value, "Missing enum constant value: '" + String(class_name) + "." + String(constant_name) + "'.");
+
+			ConstantData constant;
+			constant.name = constant_name;
+			constant.value = *value;
+
+			exposed_class.constants.push_back(constant);
+		}
+
+		r_context.exposed_classes.insert(class_name, exposed_class);
+		class_list.pop_front();
+	}
+
+	TEST_END();
+}
+
+void add_builtin_types(Context &r_context) {
+	// NOTE: We don't care about the size and sign of int and float in these tests
+	for (int i = 0; i < Variant::VARIANT_MAX; i++) {
+		r_context.builtin_types.push_back(Variant::get_type_name(Variant::Type(i)));
+	}
+
+	r_context.builtin_types.push_back(_STR(Variant));
+	r_context.builtin_types.push_back(r_context.names_cache.vararg_stub_type);
+	r_context.builtin_types.push_back("void");
+}
+
+void add_global_enums(Context &r_context) {
+	int global_constants_count = GlobalConstants::get_global_constant_count();
+
+	if (global_constants_count > 0) {
+		for (int i = 0; i < global_constants_count; i++) {
+			StringName enum_name = GlobalConstants::get_global_constant_enum(i);
+
+			if (enum_name != StringName()) {
+				ConstantData constant;
+				constant.name = GlobalConstants::get_global_constant_name(i);
+				constant.value = GlobalConstants::get_global_constant_value(i);
+
+				EnumData enum_;
+				enum_.name = enum_name;
+				List<EnumData>::Element *enum_match = r_context.global_enums.find(enum_);
+				if (enum_match) {
+					enum_match->get().constants.push_back(constant);
+				} else {
+					enum_.constants.push_back(constant);
+					r_context.global_enums.push_back(enum_);
+				}
+			}
+		}
+
+		for (List<EnumData>::Element *E = r_context.global_enums.front(); E; E = E->next()) {
+			r_context.enum_types.push_back(E->get().name);
+		}
+	}
+
+	// HARDCODED
+	List<StringName> hardcoded_enums;
+	hardcoded_enums.push_back("Vector2.Axis");
+	hardcoded_enums.push_back("Vector2i.Axis");
+	hardcoded_enums.push_back("Vector3.Axis");
+	hardcoded_enums.push_back("Vector3i.Axis");
+	for (List<StringName>::Element *E = hardcoded_enums.front(); E; E = E->next()) {
+		// These enums are not generated and must be written manually (e.g.: Vector3.Axis)
+		// Here, we assume core types do not begin with underscore
+		r_context.enum_types.push_back(E->get());
+	}
+}
+
+TestResult run_class_db_tests() {
+	TEST_START();
+
+	Context context;
+
+	TEST_CHECK_FATAL(add_exposed_classes(context));
+	add_builtin_types(context);
+	add_global_enums(context);
+
+	const ExposedClass *object_class = context.find_exposed_class(context.names_cache.object_class);
+	TEST_FAIL_COND_FATAL(!object_class, "Object class not found.");
+	TEST_FAIL_COND_FATAL(object_class->base != StringName(),
+			"Object class derives from another class: '" + object_class->base + "'.");
+
+	for (ExposedClasses::Element E = context.exposed_classes.front(); E; E = E.next()) {
+		TEST_CHECK(validate_class(context, E.value()));
+	}
+
+	TEST_END();
+}
+
+MainLoop *test() {
+	TestResult pass = run_class_db_tests();
+
+	OS::get_singleton()->print("ClassDB tests: %s\n", pass == TestResult::PASS ? "PASS" : "FAILED");
+
+	if (pass == TestResult::FAILED) {
+		OS::get_singleton()->set_exit_code(pass == TestResult::PASS ? 0 : 1);
+	}
+
+	return nullptr;
+}
+
+} // namespace TestClassDB

main/tests/test_class_db.h

@@ -0,0 +1,42 @@
+/*************************************************************************/
+/*  test_class_db.h                                                      */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef GODOT_TEST_CLASS_DB_H
+#define GODOT_TEST_CLASS_DB_H
+
+#include "core/os/main_loop.h"
+
+namespace TestClassDB {
+
+MainLoop *test();
+
+}
+
+#endif //GODOT_TEST_CLASS_DB_H

main/tests/test_main.cpp

@@ -35,6 +35,7 @@
 #ifdef DEBUG_ENABLED
 
 #include "test_astar.h"
+#include "test_class_db.h"
 #include "test_gdscript.h"
 #include "test_gui.h"
 #include "test_math.h"
@@ -54,6 +55,7 @@ const char **tests_get_names() {
 		"physics_3d",
 		"render",
 		"oa_hash_map",
+		"class_db",
 		"gui",
 		"shaderlang",
 		"gd_tokenizer",
@@ -93,6 +95,10 @@ MainLoop *test_main(String p_test, const List<String> &p_args) {
 		return TestOAHashMap::test();
 	}
 
+	if (p_test == "class_db") {
+		return TestClassDB::test();
+	}
+
 #ifndef _3D_DISABLED
 	if (p_test == "gui") {
 		return TestGUI::test();

modules/mono/editor/bindings_generator.cpp

@@ -123,9 +123,10 @@ static String snake_to_pascal_case(const String &p_identifier, bool p_input_is_u
 		if (part.length()) {
 			part[0] = _find_upper(part[0]);
 			if (p_input_is_upper) {
-				for (int j = 1; j < part.length(); j++)
+				for (int j = 1; j < part.length(); j++) {
 					part[j] = _find_lower(part[j]);
 				}
+			}
 			ret += part;
 		} else {
 			if (i == 0 || i == (parts.size() - 1)) {
@@ -157,9 +158,10 @@ static String snake_to_camel_case(const String &p_identifier, bool p_input_is_up
 				part[0] = _find_upper(part[0]);
 			}
 			if (p_input_is_upper) {
-				for (int j = i != 0 ? 1 : 0; j < part.length(); j++)
+				for (int j = i != 0 ? 1 : 0; j < part.length(); j++) {
 					part[j] = _find_lower(part[j]);
 				}
+			}
 			ret += part;
 		} else {
 			if (i == 0 || i == (parts.size() - 1)) {
@@ -182,8 +184,9 @@ static String snake_to_camel_case(const String &p_identifier, bool p_input_is_up
 String BindingsGenerator::bbcode_to_xml(const String &p_bbcode, const TypeInterface *p_itype) {
 	// Based on the version in EditorHelp
 
-	if (p_bbcode.empty())
+	if (p_bbcode.empty()) {
 		return String();
+	}
 
 	DocData *doc = EditorHelp::get_doc_data();
 
@@ -200,8 +203,9 @@ String BindingsGenerator::bbcode_to_xml(const String &p_bbcode, const TypeInterf
 	while (pos < bbcode.length()) {
 		int brk_pos = bbcode.find("[", pos);
 
-		if (brk_pos < 0)
+		if (brk_pos < 0) {
 			brk_pos = bbcode.length();
+		}
 
 		if (brk_pos > pos) {
 			String text = bbcode.substr(pos, brk_pos - pos);
@@ -210,19 +214,22 @@ String BindingsGenerator::bbcode_to_xml(const String &p_bbcode, const TypeInterf
 			} else {
 				Vector<String> lines = text.split("\n");
 				for (int i = 0; i < lines.size(); i++) {
-					if (i != 0)
+					if (i != 0) {
 						xml_output.append("<para>");
+					}
 
 					xml_output.append(lines[i].xml_escape());
 
-					if (i != lines.size() - 1)
+					if (i != lines.size() - 1) {
 						xml_output.append("</para>\n");
 					}
 				}
 			}
+		}
 
-		if (brk_pos == bbcode.length())
+		if (brk_pos == bbcode.length()) {
 			break; // nothing else to add
+		}
 
 		int brk_end = bbcode.find("]", brk_pos + 1);
 
@@ -233,15 +240,17 @@ String BindingsGenerator::bbcode_to_xml(const String &p_bbcode, const TypeInterf
 			} else {
 				Vector<String> lines = text.split("\n");
 				for (int i = 0; i < lines.size(); i++) {
-					if (i != 0)
+					if (i != 0) {
 						xml_output.append("<para>");
+					}
 
 					xml_output.append(lines[i].xml_escape());
 
-					if (i != lines.size() - 1)
+					if (i != lines.size() - 1) {
 						xml_output.append("</para>\n");
 					}
 				}
+			}
 
 			break;
 		}
@@ -412,9 +421,10 @@ String BindingsGenerator::bbcode_to_xml(const String &p_bbcode, const TypeInterf
 						for (const List<EnumInterface>::Element *E = global_enums.front(); E; E = E->next()) {
 							target_ienum = &E->get();
 							target_iconst = find_constant_by_name(target_name, target_ienum->constants);
-							if (target_iconst)
+							if (target_iconst) {
 								break;
 							}
+						}
 
 						if (target_iconst) {
 							xml_output.append("<see cref=\"" BINDINGS_NAMESPACE ".");
@@ -450,9 +460,10 @@ String BindingsGenerator::bbcode_to_xml(const String &p_bbcode, const TypeInterf
 						for (const List<EnumInterface>::Element *E = target_itype->enums.front(); E; E = E->next()) {
 							target_ienum = &E->get();
 							target_iconst = find_constant_by_name(target_name, target_ienum->constants);
-							if (target_iconst)
+							if (target_iconst) {
 								break;
 							}
+						}
 
 						if (target_iconst) {
 							xml_output.append("<see cref=\"" BINDINGS_NAMESPACE ".");
@@ -583,8 +594,9 @@ String BindingsGenerator::bbcode_to_xml(const String &p_bbcode, const TypeInterf
 			tag_stack.push_front(tag);
 		} else if (tag == "url") {
 			int end = bbcode.find("[", brk_end);
-			if (end == -1)
+			if (end == -1) {
 				end = bbcode.length();
+			}
 			String url = bbcode.substr(brk_end + 1, end - brk_end - 1);
 			xml_output.append("<a href=\"");
 			xml_output.append(url);
@@ -603,8 +615,9 @@ String BindingsGenerator::bbcode_to_xml(const String &p_bbcode, const TypeInterf
 			tag_stack.push_front("url");
 		} else if (tag == "img") {
 			int end = bbcode.find("[", brk_end);
-			if (end == -1)
+			if (end == -1) {
 				end = bbcode.length();
+			}
 			String image = bbcode.substr(brk_end + 1, end - brk_end - 1);
 
 			// Not supported. Just append the bbcode.
@@ -640,8 +653,9 @@ int BindingsGenerator::_determine_enum_prefix(const EnumInterface &p_ienum) {
 	Vector<String> front_parts = front_iconstant.name.split("_", /* p_allow_empty: */ true);
 	int candidate_len = front_parts.size() - 1;
 
-	if (candidate_len == 0)
+	if (candidate_len == 0) {
 		return 0;
+	}
 
 	for (const List<ConstantInterface>::Element *E = p_ienum.constants.front()->next(); E; E = E->next()) {
 		const ConstantInterface &iconstant = E->get();
@@ -653,15 +667,17 @@ int BindingsGenerator::_determine_enum_prefix(const EnumInterface &p_ienum) {
 			if (front_parts[i] != parts[i]) {
 				// HARDCODED: Some Flag enums have the prefix 'FLAG_' for everything except 'FLAGS_DEFAULT' (same for 'METHOD_FLAG_' and'METHOD_FLAGS_DEFAULT').
 				bool hardcoded_exc = (i == candidate_len - 1 && ((front_parts[i] == "FLAGS" && parts[i] == "FLAG") || (front_parts[i] == "FLAG" && parts[i] == "FLAGS")));
-				if (!hardcoded_exc)
+				if (!hardcoded_exc) {
 					break;
 				}
 			}
+		}
 		candidate_len = i;
 
-		if (candidate_len == 0)
+		if (candidate_len == 0) {
 			return 0;
 		}
+	}
 
 	return candidate_len;
 }
@@ -677,22 +693,25 @@ void BindingsGenerator::_apply_prefix_to_enum_constants(BindingsGenerator::EnumI
 
 			Vector<String> parts = constant_name.split("_", /* p_allow_empty: */ true);
 
-			if (parts.size() <= curr_prefix_length)
+			if (parts.size() <= curr_prefix_length) {
 				continue;
+			}
 
 			if (parts[curr_prefix_length][0] >= '0' && parts[curr_prefix_length][0] <= '9') {
 				// The name of enum constants may begin with a numeric digit when strip from the enum prefix,
 				// so we make the prefix for this constant one word shorter in those cases.
 				for (curr_prefix_length = curr_prefix_length - 1; curr_prefix_length > 0; curr_prefix_length--) {
-					if (parts[curr_prefix_length][0] < '0' || parts[curr_prefix_length][0] > '9')
+					if (parts[curr_prefix_length][0] < '0' || parts[curr_prefix_length][0] > '9') {
 						break;
 					}
 				}
+			}
 
 			constant_name = "";
 			for (int i = curr_prefix_length; i < parts.size(); i++) {
-				if (i > curr_prefix_length)
+				if (i > curr_prefix_length) {
 					constant_name += "_";
+				}
 				constant_name += parts[i];
 			}
 
@@ -705,8 +724,9 @@ void BindingsGenerator::_generate_method_icalls(const TypeInterface &p_itype) {
 	for (const List<MethodInterface>::Element *E = p_itype.methods.front(); E; E = E->next()) {
 		const MethodInterface &imethod = E->get();
 
-		if (imethod.is_virtual)
+		if (imethod.is_virtual) {
 			continue;
+		}
 
 		const TypeInterface *return_type = _get_type_or_placeholder(imethod.return_type);
 
@@ -755,8 +775,9 @@ void BindingsGenerator::_generate_method_icalls(const TypeInterface &p_itype) {
 		List<InternalCall>::Element *match = method_icalls.find(im_icall);
 
 		if (match) {
-			if (p_itype.api_type != ClassDB::API_EDITOR)
+			if (p_itype.api_type != ClassDB::API_EDITOR) {
 				match->get().editor_only = false;
+			}
 			method_icalls_map.insert(&E->get(), &match->get());
 		} else {
 			List<InternalCall>::Element *added = method_icalls.push_back(im_icall);
@@ -801,8 +822,9 @@ void BindingsGenerator::_generate_global_constants(StringBuilder &p_output) {
 		p_output.append(";");
 	}
 
-	if (!global_constants.empty())
+	if (!global_constants.empty()) {
 		p_output.append("\n");
+	}
 
 	p_output.append(INDENT1 CLOSE_BLOCK); // end of GD class
 
@@ -864,9 +886,10 @@ void BindingsGenerator::_generate_global_constants(StringBuilder &p_output) {
 
 		p_output.append(INDENT1 CLOSE_BLOCK);
 
-		if (enum_in_static_class)
+		if (enum_in_static_class) {
 			p_output.append(INDENT1 CLOSE_BLOCK);
 		}
+	}
 
 	p_output.append(CLOSE_BLOCK); // end of namespace
 
@@ -899,8 +922,9 @@ Error BindingsGenerator::generate_cs_core_project(const String &p_proj_dir) {
 		_generate_global_constants(constants_source);
 		String output_file = path::join(base_gen_dir, BINDINGS_GLOBAL_SCOPE_CLASS "_constants.cs");
 		Error save_err = _save_file(output_file, constants_source);
-		if (save_err != OK)
+		if (save_err != OK) {
 			return save_err;
+		}
 
 		compile_items.push_back(output_file);
 	}
@@ -908,17 +932,20 @@ Error BindingsGenerator::generate_cs_core_project(const String &p_proj_dir) {
 	for (OrderedHashMap<StringName, TypeInterface>::Element E = obj_types.front(); E; E = E.next()) {
 		const TypeInterface &itype = E.get();
 
-		if (itype.api_type == ClassDB::API_EDITOR)
+		if (itype.api_type == ClassDB::API_EDITOR) {
 			continue;
+		}
 
 		String output_file = path::join(godot_objects_gen_dir, itype.proxy_name + ".cs");
 		Error err = _generate_cs_type(itype, output_file);
 
-		if (err == ERR_SKIP)
+		if (err == ERR_SKIP) {
 			continue;
+		}
 
-		if (err != OK)
+		if (err != OK) {
 			return err;
+		}
 
 		compile_items.push_back(output_file);
 	}
@@ -949,10 +976,12 @@ Error BindingsGenerator::generate_cs_core_project(const String &p_proj_dir) {
 		cs_icalls_content.append(m_icall.im_sig + ");\n");                                       \
 	}
 
-	for (const List<InternalCall>::Element *E = core_custom_icalls.front(); E; E = E->next())
+	for (const List<InternalCall>::Element *E = core_custom_icalls.front(); E; E = E->next()) {
 		ADD_INTERNAL_CALL(E->get());
-	for (const List<InternalCall>::Element *E = method_icalls.front(); E; E = E->next())
+	}
+	for (const List<InternalCall>::Element *E = method_icalls.front(); E; E = E->next()) {
 		ADD_INTERNAL_CALL(E->get());
+	}
 
 #undef ADD_INTERNAL_CALL
 
@@ -961,8 +990,9 @@ Error BindingsGenerator::generate_cs_core_project(const String &p_proj_dir) {
 	String internal_methods_file = path::join(base_gen_dir, BINDINGS_CLASS_NATIVECALLS ".cs");
 
 	Error err = _save_file(internal_methods_file, cs_icalls_content);
-	if (err != OK)
+	if (err != OK) {
 		return err;
+	}
 
 	compile_items.push_back(internal_methods_file);
 
@@ -981,8 +1011,9 @@ Error BindingsGenerator::generate_cs_core_project(const String &p_proj_dir) {
 	String includes_props_file = path::join(base_gen_dir, "GeneratedIncludes.props");
 
 	err = _save_file(includes_props_file, includes_props_content);
-	if (err != OK)
+	if (err != OK) {
 		return err;
+	}
 
 	return OK;
 }
@@ -1010,17 +1041,20 @@ Error BindingsGenerator::generate_cs_editor_project(const String &p_proj_dir) {
 	for (OrderedHashMap<StringName, TypeInterface>::Element E = obj_types.front(); E; E = E.next()) {
 		const TypeInterface &itype = E.get();
 
-		if (itype.api_type != ClassDB::API_EDITOR)
+		if (itype.api_type != ClassDB::API_EDITOR) {
 			continue;
+		}
 
 		String output_file = path::join(godot_objects_gen_dir, itype.proxy_name + ".cs");
 		Error err = _generate_cs_type(itype, output_file);
 
-		if (err == ERR_SKIP)
+		if (err == ERR_SKIP) {
 			continue;
+		}
 
-		if (err != OK)
+		if (err != OK) {
 			return err;
+		}
 
 		compile_items.push_back(output_file);
 	}
@@ -1050,10 +1084,12 @@ Error BindingsGenerator::generate_cs_editor_project(const String &p_proj_dir) {
 		cs_icalls_content.append(m_icall.im_sig + ");\n");                                  \
 	}
 
-	for (const List<InternalCall>::Element *E = editor_custom_icalls.front(); E; E = E->next())
+	for (const List<InternalCall>::Element *E = editor_custom_icalls.front(); E; E = E->next()) {
 		ADD_INTERNAL_CALL(E->get());
-	for (const List<InternalCall>::Element *E = method_icalls.front(); E; E = E->next())
+	}
+	for (const List<InternalCall>::Element *E = method_icalls.front(); E; E = E->next()) {
 		ADD_INTERNAL_CALL(E->get());
+	}
 
 #undef ADD_INTERNAL_CALL
 
@@ -1062,8 +1098,9 @@ Error BindingsGenerator::generate_cs_editor_project(const String &p_proj_dir) {
 	String internal_methods_file = path::join(base_gen_dir, BINDINGS_CLASS_NATIVECALLS_EDITOR ".cs");
 
 	Error err = _save_file(internal_methods_file, cs_icalls_content);
-	if (err != OK)
+	if (err != OK) {
 		return err;
+	}
 
 	compile_items.push_back(internal_methods_file);
 
@@ -1082,8 +1119,9 @@ Error BindingsGenerator::generate_cs_editor_project(const String &p_proj_dir) {
 	String includes_props_file = path::join(base_gen_dir, "GeneratedIncludes.props");
 
 	err = _save_file(includes_props_file, includes_props_content);
-	if (err != OK)
+	if (err != OK) {
 		return err;
+	}
 
 	return OK;
 }
@@ -1210,7 +1248,6 @@ Error BindingsGenerator::_generate_cs_type(const TypeInterface &itype, const Str
 
 	output.append(INDENT1 "{");
 
-	if (class_doc) {
 	// Add constants
 
 	for (const List<ConstantInterface>::Element *E = itype.constants.front(); E; E = E->next()) {
@@ -1240,8 +1277,9 @@ Error BindingsGenerator::_generate_cs_type(const TypeInterface &itype, const Str
 		output.append(";");
 	}
 
-		if (itype.constants.size())
+	if (itype.constants.size()) {
 		output.append("\n");
+	}
 
 	// Add enums
 
@@ -1293,9 +1331,6 @@ Error BindingsGenerator::_generate_cs_type(const TypeInterface &itype, const Str
 				"Failed to generate property '" + iprop.cname.operator String() +
 						"' for class '" + itype.name + "'.");
 	}
-	}
-
-	// TODO: BINDINGS_NATIVE_NAME_FIELD should be StringName, once we support it in C#
 
 	if (itype.is_singleton) {
 		// Add the type name and the singleton pointer as static fields
@@ -1368,16 +1403,18 @@ Error BindingsGenerator::_generate_cs_type(const TypeInterface &itype, const Str
 	if (itype.is_singleton) {
 		InternalCall singleton_icall = InternalCall(itype.api_type, ICALL_PREFIX + itype.name + SINGLETON_ICALL_SUFFIX, "IntPtr");
 
-		if (!find_icall_by_name(singleton_icall.name, custom_icalls))
+		if (!find_icall_by_name(singleton_icall.name, custom_icalls)) {
 			custom_icalls.push_back(singleton_icall);
 		}
+	}
 
 	if (is_derived_type && itype.is_instantiable) {
 		InternalCall ctor_icall = InternalCall(itype.api_type, ctor_method, "IntPtr", itype.proxy_name + " obj");
 
-		if (!find_icall_by_name(ctor_icall.name, custom_icalls))
+		if (!find_icall_by_name(ctor_icall.name, custom_icalls)) {
 			custom_icalls.push_back(ctor_icall);
 		}
+	}
 
 	output.append(INDENT1 CLOSE_BLOCK /* class */
 					CLOSE_BLOCK /* namespace */);
@@ -1442,6 +1479,9 @@ Error BindingsGenerator::_generate_cs_property(const BindingsGenerator::TypeInte
 	const TypeInterface *prop_itype = _get_type_or_null(proptype_name);
 	ERR_FAIL_NULL_V(prop_itype, ERR_BUG); // Property type not found
 
+	ERR_FAIL_COND_V_MSG(prop_itype->is_singleton, ERR_BUG,
+			"Property type is a singleton: '" + p_itype.name + "." + String(p_iprop.cname) + "'.");
+
 	if (p_iprop.prop_doc && p_iprop.prop_doc->description.size()) {
 		String xml_summary = bbcode_to_xml(fix_doc_description(p_iprop.prop_doc->description), &p_itype);
 		Vector<String> summary_lines = xml_summary.length() ? xml_summary.split("\n") : Vector<String>();
@@ -1461,8 +1501,9 @@ Error BindingsGenerator::_generate_cs_property(const BindingsGenerator::TypeInte
 
 	p_output.append(MEMBER_BEGIN "public ");
 
-	if (p_itype.is_singleton)
+	if (p_itype.is_singleton) {
 		p_output.append("static ");
+	}
 
 	p_output.append(prop_itype->cs_type);
 	p_output.append(" ");
@@ -1534,6 +1575,9 @@ Error BindingsGenerator::_generate_cs_property(const BindingsGenerator::TypeInte
 Error BindingsGenerator::_generate_cs_method(const BindingsGenerator::TypeInterface &p_itype, const BindingsGenerator::MethodInterface &p_imethod, int &p_method_bind_count, StringBuilder &p_output) {
 	const TypeInterface *return_type = _get_type_or_placeholder(p_imethod.return_type);
 
+	ERR_FAIL_COND_V_MSG(return_type->is_singleton, ERR_BUG,
+			"Method return type is a singleton: '" + p_itype.name + "." + p_imethod.name + "'.");
+
 	String method_bind_field = "__method_bind_" + itos(p_method_bind_count);
 
 	String arguments_sig;
@@ -1549,31 +1593,43 @@ Error BindingsGenerator::_generate_cs_method(const BindingsGenerator::TypeInterf
 		const ArgumentInterface &iarg = F->get();
 		const TypeInterface *arg_type = _get_type_or_placeholder(iarg.type);
 
+		ERR_FAIL_COND_V_MSG(arg_type->is_singleton, ERR_BUG,
+				"Argument type is a singleton: '" + iarg.name + "' of method '" + p_itype.name + "." + p_imethod.name + "'.");
+
+		if (iarg.default_argument.size()) {
+			CRASH_COND_MSG(!_arg_default_value_is_assignable_to_type(iarg.def_param_value, *arg_type),
+					"Invalid default value for parameter '" + iarg.name + "' of method '" + p_itype.name + "." + p_imethod.name + "'.");
+		}
+
 		// Add the current arguments to the signature
 		// If the argument has a default value which is not a constant, we will make it Nullable
 		{
-			if (F != p_imethod.arguments.front())
+			if (F != p_imethod.arguments.front()) {
 				arguments_sig += ", ";
+			}
 
-			if (iarg.def_param_mode == ArgumentInterface::NULLABLE_VAL)
+			if (iarg.def_param_mode == ArgumentInterface::NULLABLE_VAL) {
 				arguments_sig += "Nullable<";
+			}
 
 			arguments_sig += arg_type->cs_type;
 
-			if (iarg.def_param_mode == ArgumentInterface::NULLABLE_VAL)
+			if (iarg.def_param_mode == ArgumentInterface::NULLABLE_VAL) {
 				arguments_sig += "> ";
-			else
+			} else {
 				arguments_sig += " ";
+			}
 
 			arguments_sig += iarg.name;
 
 			if (iarg.default_argument.size()) {
-				if (iarg.def_param_mode != ArgumentInterface::CONSTANT)
+				if (iarg.def_param_mode != ArgumentInterface::CONSTANT) {
 					arguments_sig += " = null";
-				else
+				} else {
 					arguments_sig += " = " + sformat(iarg.default_argument, arg_type->cs_type);
 				}
 			}
+		}
 
 		icall_params += ", ";
 
@@ -1589,17 +1645,19 @@ Error BindingsGenerator::_generate_cs_method(const BindingsGenerator::TypeInterf
 			cs_in_statements += " = ";
 			cs_in_statements += iarg.name;
 
-			if (iarg.def_param_mode == ArgumentInterface::NULLABLE_VAL)
+			if (iarg.def_param_mode == ArgumentInterface::NULLABLE_VAL) {
 				cs_in_statements += ".HasValue ? ";
-			else
+			} else {
 				cs_in_statements += " != null ? ";
+			}
 
 			cs_in_statements += iarg.name;
 
-			if (iarg.def_param_mode == ArgumentInterface::NULLABLE_VAL)
+			if (iarg.def_param_mode == ArgumentInterface::NULLABLE_VAL) {
 				cs_in_statements += ".Value : ";
-			else
+			} else {
 				cs_in_statements += " : ";
+			}
 
 			String def_arg = sformat(iarg.default_argument, arg_type->cs_type);
 
@@ -1659,8 +1717,9 @@ Error BindingsGenerator::_generate_cs_method(const BindingsGenerator::TypeInterf
 		}
 
 		if (p_imethod.is_deprecated) {
-			if (p_imethod.deprecation_message.empty())
+			if (p_imethod.deprecation_message.empty()) {
 				WARN_PRINT("An empty deprecation message is discouraged. Method: '" + p_imethod.proxy_name + "'.");
+			}
 
 			p_output.append(MEMBER_BEGIN "[Obsolete(\"");
 			p_output.append(p_imethod.deprecation_message);
@@ -1720,8 +1779,9 @@ Error BindingsGenerator::_generate_cs_method(const BindingsGenerator::TypeInterf
 		im_call += ".";
 		im_call += im_icall->name;
 
-		if (p_imethod.arguments.size())
+		if (p_imethod.arguments.size()) {
 			p_output.append(cs_in_statements);
+		}
 
 		if (return_type->cname == name_cache.type_void) {
 			p_output.append(im_call + "(" + icall_params + ");\n");
@@ -1748,10 +1808,14 @@ Error BindingsGenerator::_generate_cs_signal(const BindingsGenerator::TypeInterf
 		const ArgumentInterface &iarg = F->get();
 		const TypeInterface *arg_type = _get_type_or_placeholder(iarg.type);
 
+		ERR_FAIL_COND_V_MSG(arg_type->is_singleton, ERR_BUG,
+				"Argument type is a singleton: '" + iarg.name + "' of signal" + p_itype.name + "." + p_isignal.name + "'.");
+
 		// Add the current arguments to the signature
 
-		if (F != p_isignal.arguments.front())
+		if (F != p_isignal.arguments.front()) {
 			arguments_sig += ", ";
+		}
 
 		arguments_sig += arg_type->cs_type;
 		arguments_sig += " ";
@@ -1778,8 +1842,9 @@ Error BindingsGenerator::_generate_cs_signal(const BindingsGenerator::TypeInterf
 		}
 
 		if (p_isignal.is_deprecated) {
-			if (p_isignal.deprecation_message.empty())
+			if (p_isignal.deprecation_message.empty()) {
 				WARN_PRINT("An empty deprecation message is discouraged. Signal: '" + p_isignal.proxy_name + "'.");
+			}
 
 			p_output.append(MEMBER_BEGIN "[Obsolete(\"");
 			p_output.append(p_isignal.deprecation_message);
@@ -1810,8 +1875,9 @@ Error BindingsGenerator::_generate_cs_signal(const BindingsGenerator::TypeInterf
 		// Generate event
 		p_output.append(MEMBER_BEGIN "[Signal]" MEMBER_BEGIN "public ");
 
-		if (p_itype.is_singleton)
+		if (p_itype.is_singleton) {
 			p_output.append("static ");
+		}
 
 		p_output.append("event ");
 		p_output.append(delegate_name);
@@ -1819,18 +1885,20 @@ Error BindingsGenerator::_generate_cs_signal(const BindingsGenerator::TypeInterf
 		p_output.append(p_isignal.proxy_name);
 		p_output.append("\n" OPEN_BLOCK_L2);
 
-		if (p_itype.is_singleton)
+		if (p_itype.is_singleton) {
 			p_output.append("add => Singleton.Connect(__signal_name_");
-		else
+		} else {
 			p_output.append("add => Connect(__signal_name_");
+		}
 
 		p_output.append(p_isignal.name);
 		p_output.append(", new Callable(value));\n");
 
-		if (p_itype.is_singleton)
+		if (p_itype.is_singleton) {
 			p_output.append(INDENT3 "remove => Singleton.Disconnect(__signal_name_");
-		else
+		} else {
 			p_output.append(INDENT3 "remove => Disconnect(__signal_name_");
+		}
 
 		p_output.append(p_isignal.name);
 		p_output.append(", new Callable(value));\n");
@@ -1864,7 +1932,6 @@ Error BindingsGenerator::generate_glue(const String &p_output_dir) {
 			CRASH_COND(itype.cname != name_cache.type_Object);
 			CRASH_COND(!itype.is_instantiable);
 			CRASH_COND(itype.api_type != ClassDB::API_CORE);
-			CRASH_COND(itype.is_reference);
 			CRASH_COND(itype.is_singleton);
 		}
 
@@ -1885,8 +1952,9 @@ Error BindingsGenerator::generate_glue(const String &p_output_dir) {
 			String singleton_icall_name = ICALL_PREFIX + itype.name + SINGLETON_ICALL_SUFFIX;
 			InternalCall singleton_icall = InternalCall(itype.api_type, singleton_icall_name, "IntPtr");
 
-			if (!find_icall_by_name(singleton_icall.name, custom_icalls))
+			if (!find_icall_by_name(singleton_icall.name, custom_icalls)) {
 				custom_icalls.push_back(singleton_icall);
+			}
 
 			output.append("Object* ");
 			output.append(singleton_icall_name);
@@ -1898,8 +1966,9 @@ Error BindingsGenerator::generate_glue(const String &p_output_dir) {
 		if (is_derived_type && itype.is_instantiable) {
 			InternalCall ctor_icall = InternalCall(itype.api_type, ctor_method, "IntPtr", itype.proxy_name + " obj");
 
-			if (!find_icall_by_name(ctor_icall.name, custom_icalls))
+			if (!find_icall_by_name(ctor_icall.name, custom_icalls)) {
 				custom_icalls.push_back(ctor_icall);
+			}
 
 			output.append("Object* ");
 			output.append(ctor_method);
@@ -1998,8 +2067,9 @@ Error BindingsGenerator::generate_glue(const String &p_output_dir) {
 	output.append("\n#endif // MONO_GLUE_ENABLED\n");
 
 	Error save_err = _save_file(path::join(p_output_dir, "mono_glue.gen.cpp"), output);
-	if (save_err != OK)
+	if (save_err != OK) {
 		return save_err;
+	}
 
 	OS::get_singleton()->print("Mono glue generated successfully\n");
 
@@ -2022,8 +2092,9 @@ Error BindingsGenerator::_save_file(const String &p_path, const StringBuilder &p
 }
 
 Error BindingsGenerator::_generate_glue_method(const BindingsGenerator::TypeInterface &p_itype, const BindingsGenerator::MethodInterface &p_imethod, StringBuilder &p_output) {
-	if (p_imethod.is_virtual)
+	if (p_imethod.is_virtual) {
 		return OK; // Ignore
+	}
 
 	bool ret_void = p_imethod.return_type.cname == name_cache.type_void;
 
@@ -2051,10 +2122,12 @@ Error BindingsGenerator::_generate_glue_method(const BindingsGenerator::TypeInte
 				c_in_statements += sformat(", &%s_in);\n", c_param_name);
 			}
 		} else {
-			if (i > 0)
+			if (i > 0) {
 				c_args_var_content += ", ";
-			if (arg_type->c_in.size())
+			}
+			if (arg_type->c_in.size()) {
 				c_in_statements += sformat(arg_type->c_in, arg_type->c_type, c_param_name);
+			}
 			c_args_var_content += sformat(arg_type->c_arg_in, c_param_name);
 		}
 
@@ -2084,8 +2157,9 @@ Error BindingsGenerator::_generate_glue_method(const BindingsGenerator::TypeInte
 	if (!generated_icall_funcs.find(im_icall)) {
 		generated_icall_funcs.push_back(im_icall);
 
-		if (im_icall->editor_only)
+		if (im_icall->editor_only) {
 			p_output.append("#ifdef TOOLS_ENABLED\n");
+		}
 
 		// Generate icall function
 
@@ -2203,9 +2277,10 @@ Error BindingsGenerator::_generate_glue_method(const BindingsGenerator::TypeInte
 
 		p_output.append(CLOSE_BLOCK "\n");
 
-		if (im_icall->editor_only)
+		if (im_icall->editor_only) {
 			p_output.append("#endif // TOOLS_ENABLED\n");
 		}
+	}
 
 	return OK;
 }
@@ -2213,19 +2288,22 @@ Error BindingsGenerator::_generate_glue_method(const BindingsGenerator::TypeInte
 const BindingsGenerator::TypeInterface *BindingsGenerator::_get_type_or_null(const TypeReference &p_typeref) {
 	const Map<StringName, TypeInterface>::Element *builtin_type_match = builtin_types.find(p_typeref.cname);
 
-	if (builtin_type_match)
+	if (builtin_type_match) {
 		return &builtin_type_match->get();
+	}
 
 	const OrderedHashMap<StringName, TypeInterface>::Element obj_type_match = obj_types.find(p_typeref.cname);
 
-	if (obj_type_match)
+	if (obj_type_match) {
 		return &obj_type_match.get();
+	}
 
 	if (p_typeref.is_enum) {
 		const Map<StringName, TypeInterface>::Element *enum_match = enum_types.find(p_typeref.cname);
 
-		if (enum_match)
+		if (enum_match) {
 			return &enum_match->get();
+		}
 
 		// Enum not found. Most likely because none of its constants were bound, so it's empty. That's fine. Use int instead.
 		const Map<StringName, TypeInterface>::Element *int_match = builtin_types.find(name_cache.type_int);
@@ -2239,15 +2317,17 @@ const BindingsGenerator::TypeInterface *BindingsGenerator::_get_type_or_null(con
 const BindingsGenerator::TypeInterface *BindingsGenerator::_get_type_or_placeholder(const TypeReference &p_typeref) {
 	const TypeInterface *found = _get_type_or_null(p_typeref);
 
-	if (found)
+	if (found) {
 		return found;
+	}
 
 	ERR_PRINT(String() + "Type not found. Creating placeholder: '" + p_typeref.cname.operator String() + "'.");
 
 	const Map<StringName, TypeInterface>::Element *match = placeholder_types.find(p_typeref.cname);
 
-	if (match)
+	if (match) {
 		return &match->get();
+	}
 
 	TypeInterface placeholder;
 	TypeInterface::create_placeholder_type(placeholder, p_typeref.cname);
@@ -2305,6 +2385,84 @@ StringName BindingsGenerator::_get_float_type_name_from_meta(GodotTypeInfo::Meta
 	}
 }
 
+bool BindingsGenerator::_arg_default_value_is_assignable_to_type(const Variant &p_val, const TypeInterface &p_arg_type) {
+	if (p_arg_type.name == name_cache.type_Variant) {
+		// Variant can take anything
+		return true;
+	}
+
+	switch (p_val.get_type()) {
+		case Variant::NIL:
+			return p_arg_type.is_object_type ||
+				   name_cache.is_nullable_type(p_arg_type.name);
+		case Variant::BOOL:
+			return p_arg_type.name == name_cache.type_bool;
+		case Variant::INT:
+			return p_arg_type.name == name_cache.type_sbyte ||
+				   p_arg_type.name == name_cache.type_short ||
+				   p_arg_type.name == name_cache.type_int ||
+				   p_arg_type.name == name_cache.type_byte ||
+				   p_arg_type.name == name_cache.type_ushort ||
+				   p_arg_type.name == name_cache.type_uint ||
+				   p_arg_type.name == name_cache.type_long ||
+				   p_arg_type.name == name_cache.type_ulong ||
+				   p_arg_type.name == name_cache.type_float ||
+				   p_arg_type.name == name_cache.type_double ||
+				   p_arg_type.is_enum;
+		case Variant::FLOAT:
+			return p_arg_type.name == name_cache.type_float ||
+				   p_arg_type.name == name_cache.type_double;
+		case Variant::STRING:
+		case Variant::STRING_NAME:
+			return p_arg_type.name == name_cache.type_String ||
+				   p_arg_type.name == name_cache.type_StringName ||
+				   p_arg_type.name == name_cache.type_NodePath;
+		case Variant::NODE_PATH:
+			return p_arg_type.name == name_cache.type_NodePath;
+		case Variant::TRANSFORM:
+		case Variant::TRANSFORM2D:
+		case Variant::BASIS:
+		case Variant::QUAT:
+		case Variant::PLANE:
+		case Variant::AABB:
+		case Variant::COLOR:
+		case Variant::VECTOR2:
+		case Variant::RECT2:
+		case Variant::VECTOR3:
+		case Variant::_RID:
+		case Variant::ARRAY:
+		case Variant::DICTIONARY:
+		case Variant::PACKED_BYTE_ARRAY:
+		case Variant::PACKED_INT32_ARRAY:
+		case Variant::PACKED_INT64_ARRAY:
+		case Variant::PACKED_FLOAT32_ARRAY:
+		case Variant::PACKED_FLOAT64_ARRAY:
+		case Variant::PACKED_STRING_ARRAY:
+		case Variant::PACKED_VECTOR2_ARRAY:
+		case Variant::PACKED_VECTOR3_ARRAY:
+		case Variant::PACKED_COLOR_ARRAY:
+		case Variant::CALLABLE:
+		case Variant::SIGNAL:
+			return p_arg_type.name == Variant::get_type_name(p_val.get_type());
+		case Variant::OBJECT:
+			return p_arg_type.is_object_type;
+		case Variant::VECTOR2I:
+			return p_arg_type.name == name_cache.type_Vector2 ||
+				   p_arg_type.name == Variant::get_type_name(p_val.get_type());
+		case Variant::RECT2I:
+			return p_arg_type.name == name_cache.type_Rect2 ||
+				   p_arg_type.name == Variant::get_type_name(p_val.get_type());
+		case Variant::VECTOR3I:
+			return p_arg_type.name == name_cache.type_Vector3 ||
+				   p_arg_type.name == Variant::get_type_name(p_val.get_type());
+		default:
+			CRASH_NOW_MSG("Unexpected Variant type: " + itos(p_val.get_type()));
+			break;
+	}
+
+	return false;
+}
+
 bool BindingsGenerator::_populate_object_type_interfaces() {
 	obj_types.clear();
 
@@ -2367,8 +2525,9 @@ bool BindingsGenerator::_populate_object_type_interfaces() {
 		for (const List<PropertyInfo>::Element *E = property_list.front(); E; E = E->next()) {
 			const PropertyInfo &property = E->get();
 
-			if (property.usage & PROPERTY_USAGE_GROUP || property.usage & PROPERTY_USAGE_SUBGROUP || property.usage & PROPERTY_USAGE_CATEGORY)
+			if (property.usage & PROPERTY_USAGE_GROUP || property.usage & PROPERTY_USAGE_SUBGROUP || property.usage & PROPERTY_USAGE_CATEGORY) {
 				continue;
+			}
 
 			if (property.name.find("/") >= 0) {
 				// Ignore properties with '/' (slash) in the name. These are only meant for use in the inspector.
@@ -2380,10 +2539,12 @@ bool BindingsGenerator::_populate_object_type_interfaces() {
 			iprop.setter = ClassDB::get_property_setter(type_cname, iprop.cname);
 			iprop.getter = ClassDB::get_property_getter(type_cname, iprop.cname);
 
-			if (iprop.setter != StringName())
+			if (iprop.setter != StringName()) {
 				accessor_methods[iprop.setter] = iprop.cname;
-			if (iprop.getter != StringName())
+			}
+			if (iprop.getter != StringName()) {
 				accessor_methods[iprop.getter] = iprop.cname;
+			}
 
 			bool valid = false;
 			iprop.index = ClassDB::get_property_index(type_cname, iprop.cname, &valid);
@@ -2427,20 +2588,23 @@ bool BindingsGenerator::_populate_object_type_interfaces() {
 
 			int argc = method_info.arguments.size();
 
-			if (method_info.name.empty())
+			if (method_info.name.empty()) {
 				continue;
+			}
 
 			String cname = method_info.name;
 
-			if (blacklisted_methods.find(itype.cname) && blacklisted_methods[itype.cname].find(cname))
+			if (blacklisted_methods.find(itype.cname) && blacklisted_methods[itype.cname].find(cname)) {
 				continue;
+			}
 
 			MethodInterface imethod;
 			imethod.name = method_info.name;
 			imethod.cname = cname;
 
-			if (method_info.flags & METHOD_FLAG_VIRTUAL)
+			if (method_info.flags & METHOD_FLAG_VIRTUAL) {
 				imethod.is_virtual = true;
+			}
 
 			PropertyInfo return_info = method_info.return_val;
 
@@ -2462,9 +2626,8 @@ bool BindingsGenerator::_populate_object_type_interfaces() {
 				// We assume the return type is void.
 				imethod.return_type.cname = name_cache.type_void;
 
-				// Actually, more methods like this may be added in the future,
+				// Actually, more methods like this may be added in the future, which could return
-				// which could actually will return something different.
+				// something different. Let's put this check to notify us if that ever happens.
-				// Let's put this to notify us if that ever happens.
 				if (itype.cname != name_cache.type_Object || imethod.name != "free") {
 					WARN_PRINT("Notification: New unexpected virtual non-overridable method found."
 							   " We only expected Object.free, but found '" +
@@ -2475,13 +2638,12 @@ bool BindingsGenerator::_populate_object_type_interfaces() {
 				imethod.return_type.is_enum = true;
 			} else if (return_info.class_name != StringName()) {
 				imethod.return_type.cname = return_info.class_name;
-				if (!imethod.is_virtual && ClassDB::is_parent_class(return_info.class_name, name_cache.type_Reference) && return_info.hint != PROPERTY_HINT_RESOURCE_TYPE) {
+
-					/* clang-format off */
+				bool bad_reference_hint = !imethod.is_virtual && return_info.hint != PROPERTY_HINT_RESOURCE_TYPE &&
-					ERR_PRINT("Return type is reference but hint is not '" _STR(PROPERTY_HINT_RESOURCE_TYPE) "'."
+										  ClassDB::is_parent_class(return_info.class_name, name_cache.type_Reference);
+				ERR_FAIL_COND_V_MSG(bad_reference_hint, false,
+						String() + "Return type is reference but hint is not '" _STR(PROPERTY_HINT_RESOURCE_TYPE) "'." +
 								" Are you returning a reference type by pointer? Method: '" + itype.name + "." + imethod.name + "'.");
-					/* clang-format on */
-					ERR_FAIL_V(false);
-				}
 			} else if (return_info.hint == PROPERTY_HINT_RESOURCE_TYPE) {
 				imethod.return_type.cname = return_info.hint_string;
 			} else if (return_info.type == Variant::NIL && return_info.usage & PROPERTY_USAGE_NIL_IS_VARIANT) {
@@ -2572,6 +2734,10 @@ bool BindingsGenerator::_populate_object_type_interfaces() {
 				}
 			}
 
+			ERR_FAIL_COND_V_MSG(itype.find_property_by_name(imethod.cname), false,
+					"Method name conflicts with property: '" + itype.name + "." + imethod.name + "'.");
+
+			// Classes starting with an underscore are ignored unless they're used as a property setter or getter
 			if (!imethod.is_virtual && imethod.name[0] == '_') {
 				for (const List<PropertyInterface>::Element *F = itype.properties.front(); F; F = F->next()) {
 					const PropertyInterface &iprop = F->get();
@@ -2751,7 +2917,8 @@ bool BindingsGenerator::_populate_object_type_interfaces() {
 }
 
 bool BindingsGenerator::_arg_default_value_from_variant(const Variant &p_val, ArgumentInterface &r_iarg) {
-	r_iarg.default_argument = p_val;
+	r_iarg.def_param_value = p_val;
+	r_iarg.default_argument = p_val.operator String();
 
 	switch (p_val.get_type()) {
 		case Variant::NIL:
@@ -2784,8 +2951,9 @@ bool BindingsGenerator::_arg_default_value_from_variant(const Variant &p_val, Ar
 			}
 			break;
 		case Variant::TRANSFORM:
-			if (p_val.operator Transform() == Transform())
+			if (p_val.operator Transform() == Transform()) {
 				r_iarg.default_argument.clear();
+			}
 			r_iarg.default_argument = "new %s(" + r_iarg.default_argument + ")";
 			r_iarg.def_param_mode = ArgumentInterface::NULLABLE_VAL;
 			break;
@@ -2851,8 +3019,9 @@ bool BindingsGenerator::_arg_default_value_from_variant(const Variant &p_val, Ar
 			break;
 	}
 
-	if (r_iarg.def_param_mode == ArgumentInterface::CONSTANT && r_iarg.type.cname == name_cache.type_Variant && r_iarg.default_argument != "null")
+	if (r_iarg.def_param_mode == ArgumentInterface::CONSTANT && r_iarg.type.cname == name_cache.type_Variant && r_iarg.default_argument != "null") {
 		r_iarg.def_param_mode = ArgumentInterface::NULLABLE_REF;
+	}
 
 	return true;
 }
@@ -3357,8 +3526,9 @@ void BindingsGenerator::_initialize() {
 	core_custom_icalls.clear();
 	editor_custom_icalls.clear();
 
-	for (OrderedHashMap<StringName, TypeInterface>::Element E = obj_types.front(); E; E = E.next())
+	for (OrderedHashMap<StringName, TypeInterface>::Element E = obj_types.front(); E; E = E.next()) {
 		_generate_method_icalls(E.get());
+	}
 
 	initialized = true;
 }
@@ -3426,22 +3596,26 @@ void BindingsGenerator::handle_cmdline_args(const List<String> &p_cmdline_args)
 		}
 
 		if (glue_dir_path.length()) {
-			if (bindings_generator.generate_glue(glue_dir_path) != OK)
+			if (bindings_generator.generate_glue(glue_dir_path) != OK) {
 				ERR_PRINT(generate_all_glue_option + ": Failed to generate the C++ glue.");
+			}
 
-			if (bindings_generator.generate_cs_api(glue_dir_path.plus_file(API_SOLUTION_NAME)) != OK)
+			if (bindings_generator.generate_cs_api(glue_dir_path.plus_file(API_SOLUTION_NAME)) != OK) {
 				ERR_PRINT(generate_all_glue_option + ": Failed to generate the C# API.");
 			}
+		}
 
 		if (cs_dir_path.length()) {
-			if (bindings_generator.generate_cs_api(cs_dir_path) != OK)
+			if (bindings_generator.generate_cs_api(cs_dir_path) != OK) {
 				ERR_PRINT(generate_cs_glue_option + ": Failed to generate the C# API.");
 			}
+		}
 
 		if (cpp_dir_path.length()) {
-			if (bindings_generator.generate_glue(cpp_dir_path) != OK)
+			if (bindings_generator.generate_glue(cpp_dir_path) != OK) {
 				ERR_PRINT(generate_cpp_glue_option + ": Failed to generate the C++ glue.");
 			}
+		}
 
 		// Exit once done
 		::exit(0);

modules/mono/editor/bindings_generator.h

@@ -102,6 +102,8 @@ class BindingsGenerator {
 		TypeReference type;
 
 		String name;
+
+		Variant def_param_value;
 		DefaultParamMode def_param_mode = CONSTANT;
 
 		/**
@@ -355,36 +357,40 @@ class BindingsGenerator {
 
 		const MethodInterface *find_method_by_name(const StringName &p_cname) const {
 			for (const List<MethodInterface>::Element *E = methods.front(); E; E = E->next()) {
-				if (E->get().cname == p_cname)
+				if (E->get().cname == p_cname) {
 					return &E->get();
 				}
+			}
 
 			return nullptr;
 		}
 
 		const PropertyInterface *find_property_by_name(const StringName &p_cname) const {
 			for (const List<PropertyInterface>::Element *E = properties.front(); E; E = E->next()) {
-				if (E->get().cname == p_cname)
+				if (E->get().cname == p_cname) {
 					return &E->get();
 				}
+			}
 
 			return nullptr;
 		}
 
 		const PropertyInterface *find_property_by_proxy_name(const String &p_proxy_name) const {
 			for (const List<PropertyInterface>::Element *E = properties.front(); E; E = E->next()) {
-				if (E->get().proxy_name == p_proxy_name)
+				if (E->get().proxy_name == p_proxy_name) {
 					return &E->get();
 				}
+			}
 
 			return nullptr;
 		}
 
 		const MethodInterface *find_method_by_proxy_name(const String &p_proxy_name) const {
 			for (const List<MethodInterface>::Element *E = methods.front(); E; E = E->next()) {
-				if (E->get().proxy_name == p_proxy_name)
+				if (E->get().proxy_name == p_proxy_name) {
 					return &E->get();
 				}
+			}
 
 			return nullptr;
 		}
@@ -523,57 +529,69 @@ class BindingsGenerator {
 	void _initialize_blacklisted_methods();
 
 	struct NameCache {
-		StringName type_void;
+		StringName type_void = StaticCString::create("void");
-		StringName type_Array;
+		StringName type_Variant = StaticCString::create("Variant");
-		StringName type_Dictionary;
+		StringName type_VarArg = StaticCString::create("VarArg");
-		StringName type_Variant;
+		StringName type_Object = StaticCString::create("Object");
-		StringName type_VarArg;
+		StringName type_Reference = StaticCString::create("Reference");
-		StringName type_Object;
+		StringName type_RID = StaticCString::create("RID");
-		StringName type_Reference;
+		StringName type_String = StaticCString::create("String");
-		StringName type_RID;
+		StringName type_StringName = StaticCString::create("StringName");
-		StringName type_String;
+		StringName type_NodePath = StaticCString::create("NodePath");
-		StringName type_StringName;
+		StringName type_at_GlobalScope = StaticCString::create("@GlobalScope");
-		StringName type_NodePath;
+		StringName enum_Error = StaticCString::create("Error");
-		StringName type_at_GlobalScope;
-		StringName enum_Error;
 
-		StringName type_sbyte;
+		StringName type_sbyte = StaticCString::create("sbyte");
-		StringName type_short;
+		StringName type_short = StaticCString::create("short");
-		StringName type_int;
+		StringName type_int = StaticCString::create("int");
-		StringName type_long;
+		StringName type_byte = StaticCString::create("byte");
-		StringName type_byte;
+		StringName type_ushort = StaticCString::create("ushort");
-		StringName type_ushort;
+		StringName type_uint = StaticCString::create("uint");
-		StringName type_uint;
+		StringName type_long = StaticCString::create("long");
-		StringName type_ulong;
+		StringName type_ulong = StaticCString::create("ulong");
-		StringName type_float;
-		StringName type_double;
 
-		NameCache() {
+		StringName type_bool = StaticCString::create("bool");
-			type_void = StaticCString::create("void");
+		StringName type_float = StaticCString::create("float");
-			type_Array = StaticCString::create("Array");
+		StringName type_double = StaticCString::create("double");
-			type_Dictionary = StaticCString::create("Dictionary");
-			type_Variant = StaticCString::create("Variant");
-			type_VarArg = StaticCString::create("VarArg");
-			type_Object = StaticCString::create("Object");
-			type_Reference = StaticCString::create("Reference");
-			type_RID = StaticCString::create("RID");
-			type_String = StaticCString::create("String");
-			type_StringName = StaticCString::create("StringName");
-			type_NodePath = StaticCString::create("NodePath");
-			type_at_GlobalScope = StaticCString::create("@GlobalScope");
-			enum_Error = StaticCString::create("Error");
 
-			type_sbyte = StaticCString::create("sbyte");
+		StringName type_Vector2 = StaticCString::create("Vector2");
-			type_short = StaticCString::create("short");
+		StringName type_Rect2 = StaticCString::create("Rect2");
-			type_int = StaticCString::create("int");
+		StringName type_Vector3 = StaticCString::create("Vector3");
-			type_long = StaticCString::create("long");
+
-			type_byte = StaticCString::create("byte");
+		// Object not included as it must be checked for all derived classes
-			type_ushort = StaticCString::create("ushort");
+		static constexpr int nullable_types_count = 17;
-			type_uint = StaticCString::create("uint");
+		StringName nullable_types[nullable_types_count] = {
-			type_ulong = StaticCString::create("ulong");
+			type_String,
-			type_float = StaticCString::create("float");
+			type_StringName,
-			type_double = StaticCString::create("double");
+			type_NodePath,
+
+			StaticCString::create(_STR(Array)),
+			StaticCString::create(_STR(Dictionary)),
+			StaticCString::create(_STR(Callable)),
+			StaticCString::create(_STR(Signal)),
+
+			StaticCString::create(_STR(PackedByteArray)),
+			StaticCString::create(_STR(PackedInt32Array)),
+			StaticCString::create(_STR(PackedInt64rray)),
+			StaticCString::create(_STR(PackedFloat32Array)),
+			StaticCString::create(_STR(PackedFloat64Array)),
+			StaticCString::create(_STR(PackedStringArray)),
+			StaticCString::create(_STR(PackedVector2Array)),
+			StaticCString::create(_STR(PackedVector3Array)),
+			StaticCString::create(_STR(PackedColorArray)),
+		};
+
+		bool is_nullable_type(const StringName &p_type) const {
+			for (int i = 0; i < nullable_types_count; i++) {
+				if (p_type == nullable_types[i]) {
+					return true;
 				}
+			}
+
+			return false;
+		}
+
+		NameCache() {}
 
 	private:
 		NameCache(const NameCache &);
@@ -585,8 +603,9 @@ class BindingsGenerator {
 	const List<InternalCall>::Element *find_icall_by_name(const String &p_name, const List<InternalCall> &p_list) {
 		const List<InternalCall>::Element *it = p_list.front();
 		while (it) {
-			if (it->get().name == p_name)
+			if (it->get().name == p_name) {
 				return it;
+			}
 			it = it->next();
 		}
 		return nullptr;
@@ -594,20 +613,22 @@ class BindingsGenerator {
 
 	const ConstantInterface *find_constant_by_name(const String &p_name, const List<ConstantInterface> &p_constants) const {
 		for (const List<ConstantInterface>::Element *E = p_constants.front(); E; E = E->next()) {
-			if (E->get().name == p_name)
+			if (E->get().name == p_name) {
 				return &E->get();
 			}
+		}
 
 		return nullptr;
 	}
 
 	inline String get_unique_sig(const TypeInterface &p_type) {
-		if (p_type.is_reference)
+		if (p_type.is_reference) {
 			return "Ref";
-		else if (p_type.is_object_type)
+		} else if (p_type.is_object_type) {
 			return "Obj";
-		else if (p_type.is_enum)
+		} else if (p_type.is_enum) {
 			return "int";
+		}
 
 		return p_type.name;
 	}
@@ -626,6 +647,7 @@ class BindingsGenerator {
 	StringName _get_float_type_name_from_meta(GodotTypeInfo::Metadata p_meta);
 
 	bool _arg_default_value_from_variant(const Variant &p_val, ArgumentInterface &r_iarg);
+	bool _arg_default_value_is_assignable_to_type(const Variant &p_val, const TypeInterface &p_arg_type);
 
 	bool _populate_object_type_interfaces();
 	void _populate_builtin_type_interfaces();