diff --git a/src/libstore/include/nix/store/legacy-ssh-store.hh b/src/libstore/include/nix/store/legacy-ssh-store.hh
index 994918f90f0..8b18176b10e 100644
--- a/src/libstore/include/nix/store/legacy-ssh-store.hh
+++ b/src/libstore/include/nix/store/legacy-ssh-store.hh
@@ -214,6 +214,12 @@ public:
     {
         unsupported("queryRealisation");
     }
+
+    StorePathSet querySubstitutablePaths(const StorePathSet & paths) override
+    {
+        // not supported
+        return {};
+    }
 };
 
 } // namespace nix
diff --git a/src/libstore/include/nix/store/local-store.hh b/src/libstore/include/nix/store/local-store.hh
index b5de22095b8..adbf2b26efe 100644
--- a/src/libstore/include/nix/store/local-store.hh
+++ b/src/libstore/include/nix/store/local-store.hh
@@ -232,8 +232,6 @@ public:
 
     std::optional<StorePath> queryPathFromHashPart(const std::string & hashPart) override;
 
-    StorePathSet querySubstitutablePaths(const StorePathSet & paths) override;
-
     bool pathInfoIsUntrusted(const ValidPathInfo &) override;
     bool realisationIsUntrusted(const Realisation &) override;
 
diff --git a/src/libstore/include/nix/store/store-api.hh b/src/libstore/include/nix/store/store-api.hh
index 3261a553e21..c4c9bc93051 100644
--- a/src/libstore/include/nix/store/store-api.hh
+++ b/src/libstore/include/nix/store/store-api.hh
@@ -497,10 +497,7 @@ public:
     /**
      * Query which of the given paths have substitutes.
      */
-    virtual StorePathSet querySubstitutablePaths(const StorePathSet & paths)
-    {
-        return {};
-    };
+    virtual StorePathSet querySubstitutablePaths(const StorePathSet & paths);
 
     /**
      * Query substitute info (i.e. references, derivers and download
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 70ce6b4f28b..4b92d752291 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -867,40 +867,6 @@ std::optional<StorePath> LocalStore::queryPathFromHashPart(const std::string & h
     });
 }
 
-StorePathSet LocalStore::querySubstitutablePaths(const StorePathSet & paths)
-{
-    if (!settings.useSubstitutes)
-        return StorePathSet();
-
-    StorePathSet remaining;
-    for (auto & i : paths)
-        remaining.insert(i);
-
-    StorePathSet res;
-
-    for (auto & sub : getDefaultSubstituters()) {
-        if (remaining.empty())
-            break;
-        if (sub->storeDir != storeDir)
-            continue;
-        if (!sub->config.wantMassQuery)
-            continue;
-
-        auto valid = sub->queryValidPaths(remaining);
-
-        StorePathSet remaining2;
-        for (auto & path : remaining)
-            if (valid.count(path))
-                res.insert(path);
-            else
-                remaining2.insert(path);
-
-        std::swap(remaining, remaining2);
-    }
-
-    return res;
-}
-
 void LocalStore::registerValidPath(const ValidPathInfo & info)
 {
     registerValidPaths({{info.path, info}});
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index fc05667157e..647787df224 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -471,6 +471,40 @@ void Store::querySubstitutablePathInfos(const StorePathCAMap & paths, Substituta
     }
 }
 
+StorePathSet Store::querySubstitutablePaths(const StorePathSet & paths)
+{
+    if (!settings.useSubstitutes)
+        return StorePathSet();
+
+    StorePathSet remaining;
+    for (auto & i : paths)
+        remaining.insert(i);
+
+    StorePathSet res;
+
+    for (auto & sub : getDefaultSubstituters()) {
+        if (remaining.empty())
+            break;
+        if (sub->storeDir != storeDir)
+            continue;
+        if (!sub->config.wantMassQuery)
+            continue;
+
+        auto valid = sub->queryValidPaths(remaining);
+
+        StorePathSet remaining2;
+        for (auto & path : remaining)
+            if (valid.count(path))
+                res.insert(path);
+            else
+                remaining2.insert(path);
+
+        std::swap(remaining, remaining2);
+    }
+
+    return res;
+}
+
 bool Store::isValidPath(const StorePath & storePath)
 {
     auto res = pathInfoCache->lock()->get(storePath);