diff --git a/include/loki/domain/pddl/type.hpp b/include/loki/domain/pddl/type.hpp
index b4eda99b..3da5e7bd 100644
--- a/include/loki/domain/pddl/type.hpp
+++ b/include/loki/domain/pddl/type.hpp
@@ -37,7 +37,7 @@ class TypeImpl : public Base<TypeImpl> {
     std::string m_name;
     TypeList m_bases;
 
-    TypeImpl(int identifier, std::string name, TypeList bases = {});
+    TypeImpl(int identifier, std::string name, TypeList bases);
 
     // Give access to the constructor.
     template<typename HolderType, ElementsPerSegment N>
diff --git a/src/domain/parser.cpp b/src/domain/parser.cpp
index 4dc5baa1..f95c761d 100644
--- a/src/domain/parser.cpp
+++ b/src/domain/parser.cpp
@@ -59,8 +59,8 @@ DomainParser::DomainParser(const fs::path& file_path)
     context.scopes.open_scope();
 
     // Create base types.
-    const auto base_type_object = context.factories.types.get_or_create<pddl::TypeImpl>("object");
-    const auto base_type_number = context.factories.types.get_or_create<pddl::TypeImpl>("number");
+    const auto base_type_object = context.factories.types.get_or_create<pddl::TypeImpl>("object", pddl::TypeList());
+    const auto base_type_number = context.factories.types.get_or_create<pddl::TypeImpl>("number", pddl::TypeList());
     context.scopes.insert("object", base_type_object, {});
     context.scopes.insert("number", base_type_number, {});
 
diff --git a/src/domain/pddl/parser/parameters.cpp b/src/domain/pddl/parser/parameters.cpp
index 16913203..3a2ee9c9 100644
--- a/src/domain/pddl/parser/parameters.cpp
+++ b/src/domain/pddl/parser/parameters.cpp
@@ -72,7 +72,7 @@ ParameterListVisitor::ParameterListVisitor(Context& context_)
 
 pddl::ParameterList ParameterListVisitor::operator()(const std::vector<ast::Variable>& nodes) {
     // std::vector<ast::Variable> has single base type "object"
-    const auto type = context.factories.types.get_or_create<pddl::TypeImpl>("object");
+    const auto type = context.factories.types.get_or_create<pddl::TypeImpl>("object", pddl::TypeList());
     auto parameter_list = parse_parameter_definitions(nodes, pddl::TypeList{type}, context);
     return parameter_list;
 }
diff --git a/src/domain/pddl/parser/types.cpp b/src/domain/pddl/parser/types.cpp
index 70f07c27..8f8ac0ba 100644
--- a/src/domain/pddl/parser/types.cpp
+++ b/src/domain/pddl/parser/types.cpp
@@ -32,20 +32,20 @@ TypeDeclarationTypeVisitor::TypeDeclarationTypeVisitor(Context& context_)
     : context(context_) { }
 
 pddl::TypeList TypeDeclarationTypeVisitor::operator()(const ast::TypeObject& node) {
-    const auto type = context.factories.types.get_or_create<pddl::TypeImpl>("object");
+    const auto type = context.factories.types.get_or_create<pddl::TypeImpl>("object", pddl::TypeList());
     context.positions.push_back(type, node);
     return { type };
 }
 
 pddl::TypeList TypeDeclarationTypeVisitor::operator()(const ast::TypeNumber& node) {
-    const auto type = context.factories.types.get_or_create<pddl::TypeImpl>("number");
+    const auto type = context.factories.types.get_or_create<pddl::TypeImpl>("number", pddl::TypeList());
     context.positions.push_back(type, node);
     return { type };
 }
 
 pddl::TypeList TypeDeclarationTypeVisitor::operator()(const domain::ast::Name& node) {
     auto name = parse(node);
-    const auto type = context.factories.types.get_or_create<pddl::TypeImpl>(name);
+    const auto type = context.factories.types.get_or_create<pddl::TypeImpl>(name, pddl::TypeList());
     context.positions.push_back(type, node);
     return { type };
 }