diff --git a/src/libstore/dummy-store.cc b/src/libstore/dummy-store.cc
index f52a309d1..e4f13b8f4 100644
--- a/src/libstore/dummy-store.cc
+++ b/src/libstore/dummy-store.cc
@@ -58,6 +58,15 @@ struct DummyStore : public virtual DummyStoreConfig, public virtual Store
         RepairFlag repair, CheckSigsFlag checkSigs) override
     { unsupported("addToStore"); }
 
+    virtual StorePath addToStoreFromDump(
+        Source & dump,
+        std::string_view name,
+        ContentAddressMethod method = FileIngestionMethod::Recursive,
+        HashAlgorithm hashAlgo = HashAlgorithm::SHA256,
+        const StorePathSet & references = StorePathSet(),
+        RepairFlag repair = NoRepair) override
+    { unsupported("addToStore"); }
+
     void narFromPath(const StorePath & path, Sink & sink) override
     { unsupported("narFromPath"); }
 
diff --git a/src/libstore/legacy-ssh-store.hh b/src/libstore/legacy-ssh-store.hh
index c5a3ce677..7cee31d66 100644
--- a/src/libstore/legacy-ssh-store.hh
+++ b/src/libstore/legacy-ssh-store.hh
@@ -69,6 +69,15 @@ struct LegacySSHStore : public virtual LegacySSHStoreConfig, public virtual Stor
         RepairFlag repair) override
     { unsupported("addToStore"); }
 
+    virtual StorePath addToStoreFromDump(
+        Source & dump,
+        std::string_view name,
+        ContentAddressMethod method = FileIngestionMethod::Recursive,
+        HashAlgorithm hashAlgo = HashAlgorithm::SHA256,
+        const StorePathSet & references = StorePathSet(),
+        RepairFlag repair = NoRepair) override
+    { unsupported("addToStore"); }
+
 private:
 
     void putBuildSettings(Connection & conn);
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 9667b5e9e..b3c935db1 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -466,8 +466,7 @@ public:
         ContentAddressMethod method = FileIngestionMethod::Recursive,
         HashAlgorithm hashAlgo = HashAlgorithm::SHA256,
         const StorePathSet & references = StorePathSet(),
-        RepairFlag repair = NoRepair)
-    { unsupported("addToStoreFromDump"); }
+        RepairFlag repair = NoRepair) = 0;
 
     /**
      * Add a mapping indicating that `deriver!outputName` maps to the output path