diff --git a/include/silo/config/util/abstract_config_source.h b/include/silo/config/util/abstract_config_source.h
index e13b1b53a..b627eeddb 100644
--- a/include/silo/config/util/abstract_config_source.h
+++ b/include/silo/config/util/abstract_config_source.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cstdint>
 #include <optional>
 #include <string>
 #include <string_view>
diff --git a/src/silo/database.cpp b/src/silo/database.cpp
index 77938ec4b..3678120b4 100644
--- a/src/silo/database.cpp
+++ b/src/silo/database.cpp
@@ -240,6 +240,8 @@ BitmapSizePerSymbol Database::calculateBitmapSizePerSymbol(
    return global_bitmap_size_per_symbol;
 }
 
+namespace {
+
 void addStatisticToBitmapContainerSize(
    const RoaringStatistics& statistic,
    BitmapContainerSizeStatistic& size_statistic
@@ -259,6 +261,8 @@ void addStatisticToBitmapContainerSize(
       statistic.n_values_bitset_containers;
 }
 
+}
+
 template <typename SymbolType>
 BitmapContainerSize Database::calculateBitmapContainerSizePerGenomeSection(
    const SequenceStore<SymbolType>& seq_store,
@@ -474,6 +478,7 @@ void Database::saveDatabaseState(const std::filesystem::path& save_directory) {
    data_version_.saveToFile(data_version_file);
 }
 
+namespace {
 DataVersion loadDataVersion(const std::filesystem::path& filename) {
    if (!std::filesystem::is_regular_file(filename)) {
       auto error = fmt::format("Input file {} could not be opened.", filename.string());
@@ -489,6 +494,7 @@ DataVersion loadDataVersion(const std::filesystem::path& filename) {
    }
    return data_version.value();
 }
+}
 
 Database Database::loadDatabaseState(const std::filesystem::path& save_directory) {
    Database database;
diff --git a/src/silo/storage/position.test.cpp b/src/silo/storage/position.test.cpp
index 97a45de82..3fb620981 100644
--- a/src/silo/storage/position.test.cpp
+++ b/src/silo/storage/position.test.cpp
@@ -14,6 +14,7 @@
 using silo::Nucleotide;
 using silo::Position;
 
+namespace {
 void serializeToFile(const std::string& filename, const Position<Nucleotide>& position) {
    std::ofstream output_file(filename.c_str(), std::ios::binary);
    ::boost::archive::binary_oarchive output_archive(output_file);
@@ -27,6 +28,7 @@ void deserializeFromFile(const std::string& filename, Position<Nucleotide>& posi
    input_archive >> position;
    input_file.close();
 }
+}
 
 TEST(Position, flipsMostNumerousCorrectlyFromInitiallyUnoptimized) {
    Position<Nucleotide> under_test;