diff --git a/include/mbgl/storage/default/default_file_source.hpp b/include/mbgl/storage/default/default_file_source.hpp
index 189ff7b9e..21048e99e 100644
--- a/include/mbgl/storage/default/default_file_source.hpp
+++ b/include/mbgl/storage/default/default_file_source.hpp
@@ -47,7 +47,7 @@ private:
 
     SharedRequestBase *find(const Resource &resource);
 
-    std::unordered_map<Resource, SharedRequestBase *> pending;
+    std::unordered_map<Resource, SharedRequestBase *, Resource::Hash> pending;
 
     uv_loop_t *loop = nullptr;
     FileCache *cache = nullptr;
diff --git a/include/mbgl/storage/resource.hpp b/include/mbgl/storage/resource.hpp
index e499f84a2..cfd52caa7 100644
--- a/include/mbgl/storage/resource.hpp
+++ b/include/mbgl/storage/resource.hpp
@@ -21,17 +21,13 @@ struct Resource {
     inline bool operator==(const Resource &res) const {
         return kind == res.kind && url == res.url;
     }
-};
 
-}
+    struct Hash {
+        std::size_t operator()(Resource const& r) const {
+            return std::hash<std::string>()(r.url) ^ (std::hash<uint8_t>()(r.kind) << 1);
+        }
+    };
 
-// Specialize std::hash for use in std::unordered_map
-namespace std {
-
-template<> struct hash<mbgl::Resource> {
-    std::size_t operator()(mbgl::Resource const& r) const {
-        return std::hash<std::string>()(r.url) ^ (std::hash<uint8_t>()(r.kind) << 1);
-    }
 };
 
 }