Don't try and set empty aggregates (todo: see if they are still needed with the type-aware upgrade-based parse mode)

src/ifcparse/parse.cpp

@@ -2616,6 +2616,8 @@ express::Base file::add_entity(const express::Base& entity, int id) {
             if constexpr (std::is_same_v<U, express::Base>) {
             } else if constexpr (std::is_same_v<U, std::vector<express::Base>>) {
             } else if constexpr (std::is_same_v<U, std::vector<std::vector<express::Base>>>) {
+            } else if constexpr (std::is_same_v<U, empty_aggregate_t>) {
+            } else if constexpr (std::is_same_v<U, empty_aggregate_of_aggregate_t>) {
             } else {
                 new_entity.set_attribute_value(i, v);
             }

src/ifcparse/spf_header.cpp

@@ -108,6 +108,8 @@ void ifcopenshell::spf_header::assign(const spf_header& other) {
                     if constexpr (std::is_same_v<U, express::Base>) {
                     } else if constexpr (std::is_same_v<U, std::vector<express::Base>>) {
                     } else if constexpr (std::is_same_v<U, std::vector<std::vector<express::Base>>>) {
+                    } else if constexpr (std::is_same_v<U, empty_aggregate_t>) {
+                    } else if constexpr (std::is_same_v<U, empty_aggregate_of_aggregate_t>) {
                     } else {
                         new_entity.set_attribute_value(i, v);
                     }