diff --git a/iguana/pb_writer.hpp b/iguana/pb_writer.hpp
index fadc6c3e..4c39305a 100644
--- a/iguana/pb_writer.hpp
+++ b/iguana/pb_writer.hpp
@@ -206,6 +206,8 @@ IGUANA_INLINE void to_pb_impl(Type&& t, It&& it, uint32_t*& sz_ptr) {
   }
 }
 
+#if defined(__clang__) || defined(_MSC_VER) || \
+    (defined(__GNUC__) && __GNUC__ > 8)
 template <typename T>
 IGUANA_INLINE constexpr std::string_view get_type_string() {
   if constexpr (std::is_integral_v<T>) {
@@ -443,7 +445,7 @@ IGUANA_INLINE void build_sub_proto(Map& map, std::string_view str_type,
     map.emplace(str_type, std::move(sub_str));
   }
 }
-
+#endif
 }  // namespace detail
 
 template <typename T, typename Stream>
@@ -455,6 +457,8 @@ IGUANA_INLINE void to_pb(T& t, Stream& out) {
   detail::to_pb_impl<0>(t, &out[0], sz_ptr);
 }
 
+#if defined(__clang__) || defined(_MSC_VER) || \
+    (defined(__GNUC__) && __GNUC__ > 8)
 template <typename T, bool gen_header = true, typename Stream>
 IGUANA_INLINE void to_proto(Stream& out, std::string_view ns = "") {
   if (gen_header) {
@@ -484,6 +488,7 @@ IGUANA_INLINE void to_proto_file(Stream& stream, std::string_view ns = "") {
   to_proto<T, gen_header>(out, ns);
   stream.write(out.data(), out.size());
 }
+#endif
 
 template <typename T, typename Stream>
 IGUANA_INLINE void to_pb_adl(iguana_adl_t* p, T& t, Stream& out) {
diff --git a/test/test_pb.cpp b/test/test_pb.cpp
index daf312ab..85e27988 100644
--- a/test/test_pb.cpp
+++ b/test/test_pb.cpp
@@ -275,6 +275,8 @@ struct vector_t {
 };
 REFLECTION(vector_t, id, color, variant, ids, pairs, strs, map, name, op_val);
 
+#if defined(__clang__) || defined(_MSC_VER) || \
+    (defined(__GNUC__) && __GNUC__ > 8)
 TEST_CASE("struct to proto") {
   {
     std::string str;
@@ -333,6 +335,7 @@ TEST_CASE("struct to proto") {
     CHECK(str.find("int32 age = 3;") != std::string::npos);
   }
 }
+#endif
 
 TEST_CASE("test reflection") {
   {
diff --git a/test/test_proto3.cpp b/test/test_proto3.cpp
index 2a50d0aa..2612b16e 100644
--- a/test/test_proto3.cpp
+++ b/test/test_proto3.cpp
@@ -297,6 +297,8 @@ TEST_CASE("test RepeatIguanaTypeMsg") {
 }
 
 TEST_CASE("test NestedMsg") {
+#if defined(__clang__) || defined(_MSC_VER) || \
+    (defined(__GNUC__) && __GNUC__ > 8)
   {
     std::string str;
     iguana::to_proto<stpb::NestedMsg>(str, "test");
@@ -305,6 +307,7 @@ TEST_CASE("test NestedMsg") {
     std::ofstream out("NestedMsg.proto", std::ios::binary);
     iguana::to_proto_file<stpb::NestedMsg>(out, "test");
   }
+#endif
   {
     stpb::NestedMsg se_st{
         /* base_msg */ stpb::BaseTypeMsg{100, 200, 300, 400, 31.4f, 62.8, false,