diff --git a/src/ifcparse/IfcGlobalId.cpp b/src/ifcparse/IfcGlobalId.cpp
index 4be2746874..d095c2b66b 100644
--- a/src/ifcparse/IfcGlobalId.cpp
+++ b/src/ifcparse/IfcGlobalId.cpp
@@ -20,6 +20,7 @@
 #include "IfcGlobalId.h"
 
 #include "IfcException.h"
+#include "IfcLogger.h"
 
 #include <algorithm>
 #include <boost/lexical_cast.hpp>
@@ -102,10 +103,10 @@ IfcParse::IfcGlobalId::IfcGlobalId() {
 
 #ifndef NDEBUG
     std::vector<unsigned char> test_vector;
-    expand(string_data, test_vector);
+    expand(string_data_, test_vector);
     boost::uuids::uuid test_uuid;
     std::copy(test_vector.begin(), test_vector.end(), test_uuid.begin());
-    if (uuid_data != test_uuid) {
+    if (uuid_data_ != test_uuid) {
         Logger::Message(Logger::LOG_ERROR, "Internal error generating GlobalId");
     }
 #endif
diff --git a/src/ifcparse/IfcLogger.cpp b/src/ifcparse/IfcLogger.cpp
index 527f871d53..0dbc359d1a 100644
--- a/src/ifcparse/IfcLogger.cpp
+++ b/src/ifcparse/IfcLogger.cpp
@@ -61,7 +61,7 @@ template <>
 const std::array<std::basic_string<wchar_t>, 5> severity_strings<wchar_t>::value = {L"Performance", L"Debug", L"Notice", L"Warning", L"Error"};
 
 template <typename T>
-void plain_text_message(T& out, const boost::optional<IfcUtil::IfcBaseClass*>& current_product, Logger::Severity type, const std::string& message, const IfcUtil::IfcBaseInterface* instance) {
+void plain_text_message(T& out, const boost::optional<const IfcUtil::IfcBaseClass*>& current_product, Logger::Severity type, const std::string& message, const IfcUtil::IfcBaseInterface* instance) {
     out << "[" << severity_strings<typename T::char_type>::value[type] << "] ";
     out << "[" << get_time(type <= Logger::LOG_PERF).c_str() << "] ";
     if (current_product) {
@@ -86,7 +86,7 @@ std::basic_string<T> string_as(const std::string& string) {
 }
 
 template <typename T>
-void json_message(T& out, const boost::optional<IfcUtil::IfcBaseClass*>& current_product, Logger::Severity type, const std::string& message, const IfcUtil::IfcBaseInterface* instance) {
+void json_message(T& out, const boost::optional<const IfcUtil::IfcBaseClass*>& current_product, Logger::Severity type, const std::string& message, const IfcUtil::IfcBaseInterface* instance) {
     boost::property_tree::basic_ptree<std::basic_string<typename T::char_type>, std::basic_string<typename T::char_type>> property_tree;
 
     // @todo this is crazy
@@ -245,7 +245,7 @@ std::stringstream Logger::log_stream_;
 Logger::Severity Logger::verbosity_ = Logger::LOG_NOTICE;
 Logger::Severity Logger::max_severity_ = Logger::LOG_NOTICE;
 Logger::Format Logger::format_ = Logger::FMT_PLAIN;
-boost::optional<IfcUtil::IfcBaseClass*> Logger::current_product_;
+boost::optional<const IfcUtil::IfcBaseClass*> Logger::current_product_;
 boost::optional<long long> Logger::first_timepoint_;
 std::map<std::string, double> Logger::performance_statistics_;
 std::map<std::string, double> Logger::performance_signal_start_;
diff --git a/src/ifcparse/IfcLogger.h b/src/ifcparse/IfcLogger.h
index b6a0b95a81..f05e88edde 100644
--- a/src/ifcparse/IfcLogger.h
+++ b/src/ifcparse/IfcLogger.h
@@ -57,7 +57,7 @@ class IFC_PARSE_API Logger {
 
     static Severity verbosity_;
     static Format format_;
-    static boost::optional<IfcUtil::IfcBaseClass*> current_product_;
+    static boost::optional<const IfcUtil::IfcBaseClass*> current_product_;
     static Severity max_severity_;
 
     static boost::optional<long long> first_timepoint_;