2 files changed, 10 insertions, 9 deletions
diff --git a/src/buildtool/storage/target_cache.hpp b/src/buildtool/storage/target_cache.hpp
index cfd8534e..a45d3999 100644
--- a/src/buildtool/storage/target_cache.hpp
+++ b/src/buildtool/storage/target_cache.hpp
@@ -162,13 +162,4 @@ using ActiveTargetCache = TargetCache<true>;
 // NOLINTNEXTLINE(misc-header-include-cycle)
 #include "src/buildtool/storage/target_cache.tpp"
 
-namespace std {
-template <>
-struct hash<TargetCacheKey> {
-    [[nodiscard]] auto operator()(TargetCacheKey const& k) const {
-        return std::hash<Artifact::ObjectInfo>{}(k.Id());
-    }
-};
-}  // namespace std
-
 #endif  // INCLUDED_SRC_BUILDTOOL_STORAGE_TARGET_CACHE_HPP
diff --git a/src/buildtool/storage/target_cache_key.hpp b/src/buildtool/storage/target_cache_key.hpp
index e5d3ee1b..f4dc0586 100644
--- a/src/buildtool/storage/target_cache_key.hpp
+++ b/src/buildtool/storage/target_cache_key.hpp
@@ -38,4 +38,14 @@ class TargetCacheKey {
     Artifact::ObjectInfo id_;
 };
 
+namespace std {
+template <>
+struct hash<TargetCacheKey> {
+    [[nodiscard]] auto operator()(TargetCacheKey const& key) const noexcept
+        -> std::size_t {
+        return std::hash<Artifact::ObjectInfo>{}(key.Id());
+    }
+};
+}  // namespace std
+
 #endif  // INCLUDED_SRC_BUILDTOOL_STORAGE_TARGET_CACHE_KEY_HPP