diff --git a/src/libexpr/paths.cc b/src/libexpr/paths.cc
index 56b740830..61c4d4100 100644
--- a/src/libexpr/paths.cc
+++ b/src/libexpr/paths.cc
@@ -21,7 +21,7 @@ std::string EvalState::encodePath(const SourcePath & path)
        to /nix/store/virtual000...<N>) and we should deprecate it
        eventually. So print a warning about use of an encoded path in
        decodePath(). */
-    return path.accessor == rootFS
+    return path.accessor == ref<InputAccessor>(rootFS)
         ? path.path.abs()
         : fmt("%s%08x-source%s", virtualPathMarker, path.accessor->number, path.path.absOrEmpty());
 }
diff --git a/src/libfetchers/fetchers.hh b/src/libfetchers/fetchers.hh
index 1b06e34b1..3e32607f9 100644
--- a/src/libfetchers/fetchers.hh
+++ b/src/libfetchers/fetchers.hh
@@ -8,7 +8,7 @@
 
 #include <memory>
 
-namespace nix { class Store; class StorePath; class InputAccessor; }
+namespace nix { class Store; class StorePath; struct InputAccessor; }
 
 namespace nix::fetchers {
 
diff --git a/src/libfetchers/mercurial.cc b/src/libfetchers/mercurial.cc
index cb7122eeb..b35c7580f 100644
--- a/src/libfetchers/mercurial.cc
+++ b/src/libfetchers/mercurial.cc
@@ -113,7 +113,7 @@ struct MercurialInputScheme : InputScheme
         const Input & input,
         const CanonPath & path,
         std::string_view contents,
-        std::optional<std::string> commitMsg) const
+        std::optional<std::string> commitMsg) const override
     {
         auto [isLocal, repoPath] = getActualUrl(input);
         if (!isLocal)
diff --git a/src/libfetchers/path.cc b/src/libfetchers/path.cc
index 96e34af79..e25be69f2 100644
--- a/src/libfetchers/path.cc
+++ b/src/libfetchers/path.cc
@@ -96,7 +96,7 @@ struct PathInputScheme : InputScheme
         const Input & input,
         const CanonPath & path,
         std::string_view contents,
-        std::optional<std::string> commitMsg) const
+        std::optional<std::string> commitMsg) const override
     {
         auto absPath = CanonPath(getAbsPath(input)) + path;