diff --git a/src/libutil/fs-sink.cc b/src/libutil/fs-sink.cc
index 597272ec9..194e86fdd 100644
--- a/src/libutil/fs-sink.cc
+++ b/src/libutil/fs-sink.cc
@@ -82,13 +82,17 @@ struct RestoreRegularFile : CreateRegularFileSink {
     void preallocateContents(uint64_t size) override;
 };
 
+static std::filesystem::path append(const std::filesystem::path & src, const CanonPath & path)
+{
+    auto dst = src;
+    if (!path.rel().empty())
+        dst /= path.rel();
+    return dst;
+}
+
 void RestoreSink::createRegularFile(const CanonPath & path, std::function<void(CreateRegularFileSink &)> func)
 {
-    auto p = dstPath;
-
-    if (!path.rel().empty()) {
-        p = p / path.rel();
-    }
+    auto p = append(dstPath, path);
 
     RestoreRegularFile crf;
     crf.fd =
@@ -140,9 +144,7 @@ void RestoreRegularFile::operator () (std::string_view data)
 
 void RestoreSink::createSymlink(const CanonPath & path, const std::string & target)
 {
-    auto p = dstPath;
-    if (!path.rel().empty())
-        p = dstPath / path.rel();
+    auto p = append(dstPath, path);
     nix::createSymlink(target, p);
 }