diff --git a/modules/gdscript/gdscript_analyzer.cpp b/modules/gdscript/gdscript_analyzer.cpp
index 6f76ca05dc4c..a0cf41d5a32d 100644
--- a/modules/gdscript/gdscript_analyzer.cpp
+++ b/modules/gdscript/gdscript_analyzer.cpp
@@ -132,6 +132,76 @@ static GDScriptParser::DataType make_builtin_meta_type(Variant::Type p_type) {
 	return type;
 }
 
+bool GDScriptAnalyzer::has_member_name_conflict_in_script_class(const StringName &p_member_name, const GDScriptParser::ClassNode *p_class) {
+	if (p_class->members_indices.has(p_member_name)) {
+		int index = p_class->members_indices[p_member_name];
+		const GDScriptParser::ClassNode::Member *member = &p_class->members[index];
+
+		if (member->type == GDScriptParser::ClassNode::Member::VARIABLE ||
+				member->type == GDScriptParser::ClassNode::Member::CONSTANT ||
+				member->type == GDScriptParser::ClassNode::Member::ENUM ||
+				member->type == GDScriptParser::ClassNode::Member::ENUM_VALUE ||
+				member->type == GDScriptParser::ClassNode::Member::CLASS ||
+				member->type == GDScriptParser::ClassNode::Member::SIGNAL) {
+			return true;
+		}
+	}
+
+	return false;
+}
+
+bool GDScriptAnalyzer::has_member_name_conflict_in_native_type(const StringName &p_member_name, const StringName &p_native_type_string) {
+	if (ClassDB::has_signal(p_native_type_string, p_member_name)) {
+		return true;
+	}
+	if (ClassDB::has_property(p_native_type_string, p_member_name)) {
+		return true;
+	}
+	if (ClassDB::has_integer_constant(p_native_type_string, p_member_name)) {
+		return true;
+	}
+
+	return false;
+}
+
+Error GDScriptAnalyzer::check_native_member_name_conflict(const StringName &p_member_name, const GDScriptParser::Node *p_member_node, const StringName &p_native_type_string) {
+	if (has_member_name_conflict_in_native_type(p_member_name, p_native_type_string)) {
+		push_error(vformat(R"(Member "%s" redefined (original in native class '%s'))", p_member_name, p_native_type_string), p_member_node);
+		return ERR_PARSE_ERROR;
+	}
+
+	if (class_exists(p_member_name)) {
+		push_error(vformat(R"(The class "%s" shadows a native class.)", p_member_name), p_member_node);
+		return ERR_PARSE_ERROR;
+	}
+
+	return OK;
+}
+
+Error GDScriptAnalyzer::check_class_member_name_conflict(const GDScriptParser::ClassNode *p_class_node, const StringName &p_member_name, const GDScriptParser::Node *p_member_node) {
+	const GDScriptParser::DataType *current_data_type = &p_class_node->base_type;
+	while (current_data_type && current_data_type->kind == GDScriptParser::DataType::Kind::CLASS) {
+		GDScriptParser::ClassNode *current_class_node = current_data_type->class_type;
+		if (has_member_name_conflict_in_script_class(p_member_name, current_class_node)) {
+			push_error(vformat(R"(The member "%s" already exists in a parent class.)", p_member_name),
+					p_member_node);
+			return ERR_PARSE_ERROR;
+		}
+		current_data_type = &current_class_node->base_type;
+	}
+
+	if (current_data_type && current_data_type->kind == GDScriptParser::DataType::Kind::NATIVE) {
+		if (current_data_type->native_type != StringName("")) {
+			return check_native_member_name_conflict(
+					p_member_name,
+					p_member_node,
+					current_data_type->native_type);
+		}
+	}
+
+	return OK;
+}
+
 Error GDScriptAnalyzer::resolve_inheritance(GDScriptParser::ClassNode *p_class, bool p_recursive) {
 	if (p_class->base_type.is_set()) {
 		// Already resolved
@@ -525,6 +595,8 @@ void GDScriptAnalyzer::resolve_class_interface(GDScriptParser::ClassNode *p_clas
 
 		switch (member.type) {
 			case GDScriptParser::ClassNode::Member::VARIABLE: {
+				check_class_member_name_conflict(p_class, member.variable->identifier->name, member.variable);
+
 				GDScriptParser::DataType datatype;
 				datatype.kind = GDScriptParser::DataType::VARIANT;
 				datatype.type_source = GDScriptParser::DataType::UNDETECTED;
@@ -598,6 +670,8 @@ void GDScriptAnalyzer::resolve_class_interface(GDScriptParser::ClassNode *p_clas
 				}
 			} break;
 			case GDScriptParser::ClassNode::Member::CONSTANT: {
+				check_class_member_name_conflict(p_class, member.constant->identifier->name, member.constant);
+
 				reduce_expression(member.constant->initializer);
 
 				GDScriptParser::DataType specified_type;
@@ -647,6 +721,8 @@ void GDScriptAnalyzer::resolve_class_interface(GDScriptParser::ClassNode *p_clas
 				}
 			} break;
 			case GDScriptParser::ClassNode::Member::SIGNAL: {
+				check_class_member_name_conflict(p_class, member.signal->identifier->name, member.signal);
+
 				for (int j = 0; j < member.signal->parameters.size(); j++) {
 					GDScriptParser::DataType signal_type = resolve_datatype(member.signal->parameters[j]->datatype_specifier);
 					signal_type.is_meta_type = false;
@@ -666,6 +742,8 @@ void GDScriptAnalyzer::resolve_class_interface(GDScriptParser::ClassNode *p_clas
 				}
 			} break;
 			case GDScriptParser::ClassNode::Member::ENUM: {
+				check_class_member_name_conflict(p_class, member.m_enum->identifier->name, member.m_enum);
+
 				GDScriptParser::DataType enum_type;
 				enum_type.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT;
 				enum_type.kind = GDScriptParser::DataType::ENUM;
@@ -717,6 +795,8 @@ void GDScriptAnalyzer::resolve_class_interface(GDScriptParser::ClassNode *p_clas
 				break;
 			case GDScriptParser::ClassNode::Member::ENUM_VALUE: {
 				if (member.enum_value.custom_value) {
+					check_class_member_name_conflict(p_class, member.enum_value.identifier->name, member.enum_value.custom_value);
+
 					current_enum = member.enum_value.parent_enum;
 					reduce_expression(member.enum_value.custom_value);
 					current_enum = nullptr;
@@ -730,6 +810,8 @@ void GDScriptAnalyzer::resolve_class_interface(GDScriptParser::ClassNode *p_clas
 						member.enum_value.resolved = true;
 					}
 				} else {
+					check_class_member_name_conflict(p_class, member.enum_value.identifier->name, member.enum_value.parent_enum);
+
 					if (member.enum_value.index > 0) {
 						member.enum_value.value = member.enum_value.parent_enum->values[member.enum_value.index - 1].value + 1;
 					} else {
@@ -742,7 +824,8 @@ void GDScriptAnalyzer::resolve_class_interface(GDScriptParser::ClassNode *p_clas
 				p_class->members.write[i].enum_value = member.enum_value;
 			} break;
 			case GDScriptParser::ClassNode::Member::CLASS:
-				break; // Done later.
+				check_class_member_name_conflict(p_class, member.m_class->identifier->name, member.m_class);
+				break;
 			case GDScriptParser::ClassNode::Member::UNDEFINED:
 				ERR_PRINT("Trying to resolve undefined member.");
 				break;
diff --git a/modules/gdscript/gdscript_analyzer.h b/modules/gdscript/gdscript_analyzer.h
index 32bf049fa129..2e17e15452bd 100644
--- a/modules/gdscript/gdscript_analyzer.h
+++ b/modules/gdscript/gdscript_analyzer.h
@@ -44,6 +44,12 @@ class GDScriptAnalyzer {
 	const GDScriptParser::EnumNode *current_enum = nullptr;
 	List<const GDScriptParser::LambdaNode *> lambda_stack;
 
+	// Tests for detecting invalid overloading of script members
+	static _FORCE_INLINE_ bool has_member_name_conflict_in_script_class(const StringName &p_name, const GDScriptParser::ClassNode *p_current_class_node);
+	static _FORCE_INLINE_ bool has_member_name_conflict_in_native_type(const StringName &p_name, const StringName &p_native_type_string);
+	Error check_native_member_name_conflict(const StringName &p_member_name, const GDScriptParser::Node *p_member_node, const StringName &p_native_type_string);
+	Error check_class_member_name_conflict(const GDScriptParser::ClassNode *p_class_node, const StringName &p_member_name, const GDScriptParser::Node *p_member_node);
+
 	Error resolve_inheritance(GDScriptParser::ClassNode *p_class, bool p_recursive = true);
 	GDScriptParser::DataType resolve_datatype(GDScriptParser::TypeNode *p_type);
 
diff --git a/modules/gdscript/gdscript_compiler.cpp b/modules/gdscript/gdscript_compiler.cpp
index ddf4f281b4d9..e5cbcc545f07 100644
--- a/modules/gdscript/gdscript_compiler.cpp
+++ b/modules/gdscript/gdscript_compiler.cpp
@@ -2186,6 +2186,13 @@ Error GDScriptCompiler::_parse_class_level(GDScript *p_script, const GDScriptPar
 	p_script->tool = parser->is_tool();
 	p_script->name = p_class->identifier ? p_class->identifier->name : "";
 
+	if (p_script->name != "") {
+		if (ClassDB::class_exists(p_script->name) && ClassDB::is_class_exposed(p_script->name)) {
+			_set_error("The class '" + p_script->name + "' shadows a native class", p_class);
+			return ERR_ALREADY_EXISTS;
+		}
+	}
+
 	Ref<GDScriptNativeClass> native;
 
 	GDScriptDataType base_type = _gdtype_from_datatype(p_class->base_type);
@@ -2337,28 +2344,6 @@ Error GDScriptCompiler::_parse_class_level(GDScript *p_script, const GDScriptPar
 				const GDScriptParser::SignalNode *signal = member.signal;
 				StringName name = signal->identifier->name;
 
-				GDScript *c = p_script;
-
-				while (c) {
-					if (c->_signals.has(name)) {
-						_set_error("Signal '" + name + "' redefined (in current or parent class)", p_class);
-						return ERR_ALREADY_EXISTS;
-					}
-
-					if (c->base.is_valid()) {
-						c = c->base.ptr();
-					} else {
-						c = nullptr;
-					}
-				}
-
-				if (native.is_valid()) {
-					if (ClassDB::has_signal(native->get_name(), name)) {
-						_set_error("Signal '" + name + "' redefined (original in native class '" + String(native->get_name()) + "')", p_class);
-						return ERR_ALREADY_EXISTS;
-					}
-				}
-
 				Vector<StringName> parameters_names;
 				parameters_names.resize(signal->parameters.size());
 				for (int j = 0; j < signal->parameters.size(); j++) {