diff --git a/src/libexpr/eval-cache.cc b/src/libexpr/eval-cache.cc
index 54fa9b741..73b10ea2e 100644
--- a/src/libexpr/eval-cache.cc
+++ b/src/libexpr/eval-cache.cc
@@ -396,8 +396,11 @@ Value & AttrCursor::forceValue()
         if (v.type() == nString)
             cachedValue = {root->db->setString(getKey(), v.string.s, v.string.context),
                            string_t{v.string.s, {}}};
-        else if (v.type() == nPath)
-            cachedValue = {root->db->setString(getKey(), v.path), string_t{v.path, {}}};
+        else if (v.type() == nPath) {
+            // FIXME: take accessor into account?
+            auto path = v.path().path;
+            cachedValue = {root->db->setString(getKey(), path), string_t{path, {}}};
+        }
         else if (v.type() == nBool)
             cachedValue = {root->db->setBool(getKey(), v.boolean), v.boolean};
         else if (v.type() == nAttrs)
@@ -537,7 +540,7 @@ std::string AttrCursor::getString()
     if (v.type() != nString && v.type() != nPath)
         throw TypeError("'%s' is not a string but %s", getAttrPathStr(), showType(v.type()));
 
-    return v.type() == nString ? v.string.s : v.path;
+    return v.type() == nString ? v.string.s : v.path().to_string();
 }
 
 string_t AttrCursor::getStringWithContext()
@@ -568,7 +571,7 @@ string_t AttrCursor::getStringWithContext()
     if (v.type() == nString)
         return {v.string.s, v.getContext(*root->state.store)};
     else if (v.type() == nPath)
-        return {v.path, {}};
+        return {v.path().to_string(), {}};
     else
         throw TypeError("'%s' is not a string but %s", getAttrPathStr(), showType(v.type()));
 }
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 93a4b99bb..88c411bd1 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -119,7 +119,7 @@ void Value::print(std::ostream & str, std::set<const void *> * seen) const
         str << "\"";
         break;
     case tPath:
-        str << path; // !!! escaping?
+        str << path().to_string(); // !!! escaping?
         break;
     case tNull:
         str << "null";
@@ -721,11 +721,6 @@ std::optional<EvalState::Doc> EvalState::getDoc(Value & v)
    evaluator.  So here are some helper functions for throwing
    exceptions. */
 
-LocalNoInlineNoReturn(void throwEvalError(const char * s, const std::string & s2))
-{
-    throw EvalError(s, s2);
-}
-
 LocalNoInlineNoReturn(void throwEvalError(const Pos & pos, const Suggestions & suggestions, const char * s, const std::string & s2))
 {
     throw EvalError(ErrorInfo {
@@ -862,9 +857,12 @@ void Value::mkStringMove(const char * s, const PathSet & context)
 }
 
 
-void Value::mkPath(std::string_view s)
+void Value::mkPath(const SourcePath & path)
 {
-    mkPath(makeImmutableString(s));
+    clearValue();
+    internalType = tPath;
+    _path.accessor = &path.accessor;
+    _path.path = makeImmutableString(path.path);
 }
 
 
@@ -978,24 +976,19 @@ Value * ExprPath::maybeThunk(EvalState & state, Env & env)
 }
 
 
-void EvalState::evalFile(const SourcePath & path_, Value & v, bool mustBeTrivial)
+void EvalState::evalFile(const SourcePath & path, Value & v, bool mustBeTrivial)
 {
-    #if 0
-    auto path = checkSourcePath(path_);
-    #endif
-
-    auto path = packPath(path_);
-
     // FIXME: use SourcePath as cache key
+    auto pathKey = path.to_string();
     FileEvalCache::iterator i;
-    if ((i = fileEvalCache.find(path)) != fileEvalCache.end()) {
+    if ((i = fileEvalCache.find(pathKey)) != fileEvalCache.end()) {
         v = i->second;
         return;
     }
 
-    auto resolvedPath_ = resolveExprPath(path_);
-    auto resolvedPath = packPath(resolvedPath_);
-    if ((i = fileEvalCache.find(resolvedPath)) != fileEvalCache.end()) {
+    auto resolvedPath = resolveExprPath(path);
+    auto resolvedPathKey = resolvedPath.to_string();
+    if ((i = fileEvalCache.find(resolvedPathKey)) != fileEvalCache.end()) {
         v = i->second;
         return;
     }
@@ -1003,17 +996,17 @@ void EvalState::evalFile(const SourcePath & path_, Value & v, bool mustBeTrivial
     printTalkative("evaluating file '%1%'", resolvedPath);
     Expr * e = nullptr;
 
-    auto j = fileParseCache.find(resolvedPath);
+    auto j = fileParseCache.find(resolvedPathKey);
     if (j != fileParseCache.end())
         e = j->second;
 
     if (!e)
-        e = parseExprFromFile(resolvedPath_);
+        e = parseExprFromFile(resolvedPath);
         #if 0
         e = parseExprFromFile(checkSourcePath(resolvedPath));
         #endif
 
-    cacheFile(path, resolvedPath, e, v, mustBeTrivial);
+    cacheFile(pathKey, resolvedPathKey, e, v, mustBeTrivial);
 }
 
 
@@ -1790,9 +1783,9 @@ void ExprConcatStrings::eval(EvalState & state, Env & env, Value & v)
                 throwEvalError(i_pos, "cannot add %1% to a float", showType(vTmp));
         } else {
             if (s.empty()) s.reserve(es->size());
-            /* skip canonization of first path, which would only be not
-            canonized in the first place if it's coming from a ./${foo} type
-            path */
+            /* Skip canonization of first path, which would only be
+               non-canonical in the first place if it's coming from a
+               ./${foo} type path. */
             auto part = state.coerceToString(i_pos, vTmp, context, false, firstType == nString, !first);
             sSize += part->size();
             s.emplace_back(std::move(part));
@@ -1808,7 +1801,7 @@ void ExprConcatStrings::eval(EvalState & state, Env & env, Value & v)
     else if (firstType == nPath) {
         if (!context.empty())
             throwEvalError(pos, "a string that refers to a store path cannot be appended to a path");
-        v.mkPath(canonPath(str()));
+        v.mkPath({.accessor = *values[0]._path.accessor, .path = canonPath(str())});
     } else
         v.mkStringMove(c_str(), context);
 }
@@ -2005,11 +1998,12 @@ BackedStringView EvalState::coerceToString(const Pos & pos, Value & v, PathSet &
     }
 
     if (v.type() == nPath) {
-        BackedStringView path(PathView(v.path));
+        auto path = v.path().to_string();
         if (canonicalizePath)
-            path = canonPath(*path);
+            // FIXME: unnecessary?
+            path = canonPath(path);
         if (copyToStore)
-            path = copyPathToStore(context, std::move(path).toOwned());
+            path = copyPathToStore(context, path);
         return path;
     }
 
@@ -2054,6 +2048,7 @@ BackedStringView EvalState::coerceToString(const Pos & pos, Value & v, PathSet &
 
 std::string EvalState::copyPathToStore(PathSet & context, const Path & path)
 {
+    #if 0
     if (nix::isDerivation(path))
         throwEvalError("file names are not allowed to end in '%1%'", drvExtension);
 
@@ -2070,7 +2065,7 @@ std::string EvalState::copyPathToStore(PathSet & context, const Path & path)
             : store->addToStore(path2.baseName(), canonPath(path), FileIngestionMethod::Recursive, htSHA256, defaultPathFilter, repair);
         #endif
         auto source = sinkToSource([&](Sink & sink) {
-            path2.accessor->dumpPath(path2.path, sink);
+            path2.dumpPath(sink);
         });
         // FIXME: readOnlyMode
         auto p = store->addToStoreFromDump(*source, path2.baseName(), FileIngestionMethod::Recursive, htSHA256, repair);
@@ -2082,15 +2077,18 @@ std::string EvalState::copyPathToStore(PathSet & context, const Path & path)
 
     context.insert(dstPath);
     return dstPath;
+    #endif
+    abort();
 }
 
 
-Path EvalState::coerceToPath(const Pos & pos, Value & v, PathSet & context)
+SourcePath EvalState::coerceToPath(const Pos & pos, Value & v, PathSet & context)
 {
     auto path = coerceToString(pos, v, context, false, false).toOwned();
     if (path == "" || path[0] != '/')
         throwEvalError(pos, "string '%1%' doesn't represent an absolute path", path);
-    return path;
+    // FIXME
+    return rootPath(path);
 }
 
 
@@ -2137,7 +2135,9 @@ bool EvalState::eqValues(Value & v1, Value & v2)
             return strcmp(v1.string.s, v2.string.s) == 0;
 
         case nPath:
-            return strcmp(v1.path, v2.path) == 0;
+            return
+                v1._path.accessor == v2._path.accessor
+                && strcmp(v1._path.path, v2._path.path) == 0;
 
         case nNull:
             return true;
diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 17fdb71dd..2de91ec9e 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -96,7 +96,7 @@ public:
     ref<FSInputAccessor> rootFS;
     ref<MemoryInputAccessor> corepkgsFS;
 
-    std::unordered_map<size_t, ref<InputAccessor>> inputAccessors;
+    std::unordered_map<InputAccessor *, ref<InputAccessor>> inputAccessors;
 
     /* Store used to materialise .drv files. */
     const ref<Store> store;
@@ -156,11 +156,9 @@ public:
 
     SearchPath getSearchPath() { return searchPath; }
 
-    Path packPath(const SourcePath & path);
+    SourcePath rootPath(Path path);
 
-    SourcePath unpackPath(const Path & path);
-
-    SourcePath rootPath(const Path & path);
+    InputAccessor & registerAccessor(ref<InputAccessor> accessor);
 
     /* Allow access to a path. */
     void allowPath(const Path & path);
@@ -274,8 +272,7 @@ public:
     /* Path coercion.  Converts strings, paths and derivations to a
        path.  The result is guaranteed to be a canonicalised, absolute
        path.  Nothing is copied to the store. */
-    // FIXME: return SourcePath
-    Path coerceToPath(const Pos & pos, Value & v, PathSet & context);
+    SourcePath coerceToPath(const Pos & pos, Value & v, PathSet & context);
 
     /* Like coerceToPath, but the result must be a store path. */
     StorePath coerceToStorePath(const Pos & pos, Value & v, PathSet & context);
diff --git a/src/libexpr/flake/flake.cc b/src/libexpr/flake/flake.cc
index 95548104d..f7a6bdaac 100644
--- a/src/libexpr/flake/flake.cc
+++ b/src/libexpr/flake/flake.cc
@@ -201,7 +201,7 @@ static std::map<FlakeId, FlakeInput> parseFlakeInputs(
 static Flake readFlake(
     EvalState & state,
     const FlakeRef & lockedRef,
-    nix::ref<InputAccessor> accessor,
+    InputAccessor & accessor,
     const InputPath & lockRootPath)
 {
     auto flakeDir = canonPath("/" + lockedRef.subdir);
@@ -213,14 +213,14 @@ static Flake readFlake(
     Value vInfo;
     state.evalFile(flakePath, vInfo, true);
 
-    expectType(state, nAttrs, vInfo, Pos(foFile, state.symbols.create(state.packPath(flakePath)), 0, 0));
+    expectType(state, nAttrs, vInfo, Pos(foFile, state.symbols.create(flakePath.to_string()), 0, 0));
 
     Flake flake {
         // FIXME
         .originalRef = lockedRef,
         .resolvedRef = lockedRef,
         .lockedRef = lockedRef,
-        .accessor = accessor,
+        .accessor = ptr(&accessor),
         .flakePath = dirOf(flakePath.path),
     };
 
@@ -308,7 +308,7 @@ static Flake getFlake(
     // FIXME: resolve
     auto [accessor, input] = originalRef.input.lazyFetch(state.store);
 
-    return readFlake(state, originalRef, accessor, lockRootPath);
+    return readFlake(state, originalRef, state.registerAccessor(accessor), lockRootPath);
 }
 
 Flake getFlake(EvalState & state, const FlakeRef & originalRef, bool allowLookup, FlakeCache & flakeCache)
@@ -324,7 +324,7 @@ Flake getFlake(EvalState & state, const FlakeRef & originalRef, bool allowLookup
 
 static LockFile readLockFile(const Flake & flake)
 {
-    SourcePath lockFilePath{flake.accessor, canonPath(flake.flakePath + "/flake.lock")};
+    SourcePath lockFilePath{*flake.accessor, canonPath(flake.flakePath + "/flake.lock")};
     return lockFilePath.pathExists()
         ? LockFile(lockFilePath.readFile(), fmt("%s", lockFilePath))
         : LockFile();
@@ -703,7 +703,7 @@ void callFlake(EvalState & state,
 
     emitTreeAttrs(
         state,
-        {lockedFlake.flake.accessor, lockedFlake.flake.flakePath},
+        {*lockedFlake.flake.accessor, lockedFlake.flake.flakePath},
         lockedFlake.flake.lockedRef.input,
         *vRootSrc,
         false,
diff --git a/src/libexpr/flake/flake.hh b/src/libexpr/flake/flake.hh
index 04a0099f5..96616b40b 100644
--- a/src/libexpr/flake/flake.hh
+++ b/src/libexpr/flake/flake.hh
@@ -61,7 +61,7 @@ struct Flake
     FlakeRef originalRef; // the original flake specification (by the user)
     FlakeRef resolvedRef; // registry references and caching resolved to the specific underlying flake
     FlakeRef lockedRef; // the specific local store result of invoking the fetcher
-    ref<InputAccessor> accessor;
+    ptr<InputAccessor> accessor;
     Path flakePath;
     bool forceDirty = false; // pretend that 'lockedRef' is dirty
     std::optional<std::string> description;
diff --git a/src/libexpr/nixexpr.hh b/src/libexpr/nixexpr.hh
index 4dbe31510..ebfeb1f74 100644
--- a/src/libexpr/nixexpr.hh
+++ b/src/libexpr/nixexpr.hh
@@ -121,9 +121,13 @@ struct ExprString : Expr
 
 struct ExprPath : Expr
 {
-    std::string s;
+    std::string s; // FIXME: remove
     Value v;
-    ExprPath(std::string s) : s(std::move(s)) { v.mkPath(this->s.c_str()); };
+    ExprPath(InputAccessor & accessor, std::string s)
+        : s(std::move(s))
+    {
+        v.mkPath({accessor, this->s});
+    }
     COMMON_METHODS
     Value * maybeThunk(EvalState & state, Env & env);
 };
diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y
index 3258327a0..ee08b1f3e 100644
--- a/src/libexpr/parser.y
+++ b/src/libexpr/parser.y
@@ -517,11 +517,11 @@ path_start
     /* add back in the trailing '/' to the first segment */
     if ($1.p[$1.l-1] == '/' && $1.l > 1)
       path += "/";
-    $$ = new ExprPath(path);
+    $$ = new ExprPath(*data->state.rootFS, path);
   }
   | HPATH {
     Path path(getHome() + std::string($1.p + 1, $1.l - 1));
-    $$ = new ExprPath(path);
+    $$ = new ExprPath(*data->state.rootFS, path);
   }
   ;
 
@@ -700,7 +700,7 @@ SourcePath resolveExprPath(const SourcePath & path)
 
     // FIXME
     auto path2 = path.path + "/default.nix";
-    if (path.accessor->pathExists(path2))
+    if (path.pathExists())
         return {path.accessor, path2};
 
     return path;
@@ -715,11 +715,11 @@ Expr * EvalState::parseExprFromFile(const SourcePath & path)
 
 Expr * EvalState::parseExprFromFile(const SourcePath & path, StaticEnv & staticEnv)
 {
-    auto packed = packPath(path);
     auto buffer = path.readFile();
     // readFile hopefully have left some extra space for terminators
     buffer.append("\0\0", 2);
-    return parse(buffer.data(), buffer.size(), foFile, packed, dirOf(packed), staticEnv);
+    // FIXME: pass SourcePaths
+    return parse(buffer.data(), buffer.size(), foFile, path.path, dirOf(path.path), staticEnv);
 }
 
 
@@ -788,7 +788,8 @@ Path EvalState::findFile(SearchPath & searchPath, const std::string_view path, c
     }
 
     if (hasPrefix(path, "nix/"))
-        return packPath(SourcePath {corepkgsFS, (std::string) path.substr(3)});
+        abort();
+        //return packPath(SourcePath {corepkgsFS, (std::string) path.substr(3)});
 
     throw ThrownError({
         .msg = hintfmt(evalSettings.pureEval
diff --git a/src/libexpr/paths.cc b/src/libexpr/paths.cc
index 16f747586..950c2b41b 100644
--- a/src/libexpr/paths.cc
+++ b/src/libexpr/paths.cc
@@ -3,34 +3,15 @@
 
 namespace nix {
 
-static constexpr std::string_view marker = "/__virtual/";
-
-Path EvalState::packPath(const SourcePath & path)
+SourcePath EvalState::rootPath(Path path)
 {
-    // FIXME: canonPath(path) ?
-    assert(hasPrefix(path.path, "/"));
-    inputAccessors.emplace(path.accessor->number, path.accessor);
-    return std::string(marker) + std::to_string(path.accessor->number) + path.path;
+    return {*rootFS, std::move(path)};
 }
 
-SourcePath EvalState::unpackPath(const Path & path)
+InputAccessor & EvalState::registerAccessor(ref<InputAccessor> accessor)
 {
-    if (hasPrefix(path, marker)) {
-        auto s = path.substr(marker.size());
-        auto slash = s.find('/');
-        auto n = std::stoi(s.substr(0, slash));
-        auto i = inputAccessors.find(n);
-        assert(i != inputAccessors.end());
-        return {i->second, slash != std::string::npos ? s.substr(slash) : "/"};
-    } else {
-        printError("FIXME: %s", path);
-        return rootPath(path);
-    }
-}
-
-SourcePath EvalState::rootPath(const Path & path)
-{
-    return {rootFS, path};
+    inputAccessors.emplace(&*accessor, accessor);
+    return *accessor;
 }
 
 }
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index f50c2dca3..26a4a4dcd 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -104,7 +104,7 @@ static SourcePath realisePath(EvalState & state, const Pos & pos, Value & v, con
     auto path = [&]()
     {
         try {
-            return state.unpackPath(state.coerceToPath(pos, v, context));
+            return state.coerceToPath(pos, v, context);
         } catch (Error & e) {
             e.addTrace(pos, "while realising the context of a path");
             throw;
@@ -557,7 +557,8 @@ struct CompareValues
             case nString:
                 return strcmp(v1->string.s, v2->string.s) < 0;
             case nPath:
-                return strcmp(v1->path, v2->path) < 0;
+                // FIXME: handle accessor?
+                return strcmp(v1->_path.path, v2->_path.path) < 0;
             case nList:
                 // Lexicographic comparison
                 for (size_t i = 0;; i++) {
@@ -1315,8 +1316,8 @@ static RegisterPrimOp primop_placeholder({
 static void prim_toPath(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
     PathSet context;
-    Path path = state.coerceToPath(pos, *args[0], context);
-    v.mkString(canonPath(path), context);
+    auto path = state.coerceToPath(pos, *args[0], context);
+    v.mkString(canonPath(path.path), context);
 }
 
 static RegisterPrimOp primop_toPath({
@@ -1347,7 +1348,7 @@ static void prim_storePath(EvalState & state, const Pos & pos, Value * * args, V
 
     PathSet context;
     // FIXME: check rootPath
-    Path path = state.coerceToPath(pos, *args[0], context);
+    auto path = state.coerceToPath(pos, *args[0], context).path;
     /* Resolve symlinks in ‘path’, unless ‘path’ itself is a symlink
        directly in the store.  The latter condition is necessary so
        e.g. nix-push does the right thing. */
@@ -1439,7 +1440,10 @@ static void prim_dirOf(EvalState & state, const Pos & pos, Value * * args, Value
     PathSet context;
     auto path = state.coerceToString(pos, *args[0], context, false, false);
     auto dir = dirOf(*path);
+    abort();
+    #if 0
     if (args[0]->type() == nPath) v.mkPath(dir); else v.mkString(dir, context);
+    #endif
 }
 
 static RegisterPrimOp primop_dirOf({
@@ -1520,8 +1524,11 @@ static void prim_findFile(EvalState & state, const Pos & pos, Value * * args, Va
 
     auto path = state.forceStringNoCtx(*args[1], pos);
 
+    #if 0
     // FIXME: checkSourcePath?
     v.mkPath(state.findFile(searchPath, path, pos));
+    #endif
+    abort();
 }
 
 static RegisterPrimOp primop_findFile(RegisterPrimOp::Info {
@@ -1563,7 +1570,7 @@ static void prim_readDir(EvalState & state, const Pos & pos, Value * * args, Val
 {
     auto path = realisePath(state, pos, *args[0]);
 
-    auto entries = path.accessor->readDirectory(path.path);
+    auto entries = path.readDirectory();
     auto attrs = state.buildBindings(entries.size());
 
     for (auto & [name, type] : entries) {
@@ -1881,7 +1888,7 @@ static RegisterPrimOp primop_toFile({
 static void addPath(
     EvalState & state,
     const Pos & pos,
-    const std::string & name,
+    std::string_view name,
     Path path,
     Value * filterFun,
     FileIngestionMethod method,
@@ -1959,7 +1966,7 @@ static void addPath(
 static void prim_filterSource(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
     PathSet context;
-    Path path = state.coerceToPath(pos, *args[1], context);
+    auto path = state.coerceToPath(pos, *args[1], context);
 
     state.forceValue(*args[0], pos);
     if (args[0]->type() != nFunction)
@@ -1970,7 +1977,8 @@ static void prim_filterSource(EvalState & state, const Pos & pos, Value * * args
             .errPos = pos
         });
 
-    addPath(state, pos, std::string(baseNameOf(path)), path, args[0], FileIngestionMethod::Recursive, std::nullopt, v, context);
+    // FIXME: use SourcePath
+    addPath(state, pos, path.baseName(), path.path, args[0], FileIngestionMethod::Recursive, std::nullopt, v, context);
 }
 
 static RegisterPrimOp primop_filterSource({
@@ -2031,7 +2039,7 @@ static RegisterPrimOp primop_filterSource({
 static void prim_path(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
     state.forceAttrs(*args[0], pos);
-    Path path;
+    std::optional<SourcePath> path;
     std::string name;
     Value * filterFun = nullptr;
     auto method = FileIngestionMethod::Recursive;
@@ -2041,7 +2049,7 @@ static void prim_path(EvalState & state, const Pos & pos, Value * * args, Value
     for (auto & attr : *args[0]->attrs) {
         auto & n(attr.name);
         if (n == "path")
-            path = state.coerceToPath(*attr.pos, *attr.value, context);
+            path.emplace(state.coerceToPath(*attr.pos, *attr.value, context));
         else if (attr.name == state.sName)
             name = state.forceStringNoCtx(*attr.value, *attr.pos);
         else if (n == "filter") {
@@ -2057,15 +2065,16 @@ static void prim_path(EvalState & state, const Pos & pos, Value * * args, Value
                 .errPos = *attr.pos
             });
     }
-    if (path.empty())
+    if (!path)
         throw EvalError({
             .msg = hintfmt("'path' required"),
             .errPos = pos
         });
     if (name.empty())
-        name = baseNameOf(path);
+        name = path->baseName();
 
-    addPath(state, pos, name, path, filterFun, method, expectedHash, v, context);
+    // FIXME: use SourcePath
+    addPath(state, pos, name, path->path, filterFun, method, expectedHash, v, context);
 }
 
 static RegisterPrimOp primop_path({
diff --git a/src/libexpr/primops/fetchTree.cc b/src/libexpr/primops/fetchTree.cc
index b9eabea3e..cc06f6495 100644
--- a/src/libexpr/primops/fetchTree.cc
+++ b/src/libexpr/primops/fetchTree.cc
@@ -30,7 +30,7 @@ void emitTreeAttrs(
     attrs.alloc(state.sOutPath).mkString(storePath, {storePath});
     #endif
 
-    attrs.alloc(state.sOutPath).mkPath(state.packPath(path));
+    attrs.alloc(state.sOutPath).mkPath(path);
 
     // FIXME: support arbitrary input attributes.
 
@@ -138,8 +138,8 @@ static void fetchTree(
                 for (auto elem : attr.value->listItems()) {
                     // FIXME: use realisePath
                     PathSet context;
-                    auto patchFile = state.unpackPath(state.coerceToPath(pos, *elem, context));
-                    patches.push_back(patchFile.accessor->readFile(patchFile.path));
+                    auto patchFile = state.coerceToPath(pos, *elem, context);
+                    patches.push_back(patchFile.readFile());
                 }
 
                 continue;
@@ -201,7 +201,7 @@ static void fetchTree(
 
     emitTreeAttrs(
         state,
-        {accessor, "/"},
+        {state.registerAccessor(accessor), "/"},
         input2,
         v,
         params.emptyRevFallback,
diff --git a/src/libexpr/value-to-json.cc b/src/libexpr/value-to-json.cc
index 517da4c01..ea5ee2a0d 100644
--- a/src/libexpr/value-to-json.cc
+++ b/src/libexpr/value-to-json.cc
@@ -32,7 +32,8 @@ void printValueAsJSON(EvalState & state, bool strict,
             break;
 
         case nPath:
-            out.write(state.copyPathToStore(context, v.path));
+            // FIXME: handle accessors
+            out.write(state.copyPathToStore(context, v.path().path));
             break;
 
         case nNull:
diff --git a/src/libexpr/value-to-xml.cc b/src/libexpr/value-to-xml.cc
index afeaf5694..20de52233 100644
--- a/src/libexpr/value-to-xml.cc
+++ b/src/libexpr/value-to-xml.cc
@@ -77,7 +77,7 @@ static void printValueAsXML(EvalState & state, bool strict, bool location,
             break;
 
         case nPath:
-            doc.writeEmptyElement("path", singletonAttrs("value", v.path));
+            doc.writeEmptyElement("path", singletonAttrs("value", v.path().to_string()));
             break;
 
         case nNull:
diff --git a/src/libexpr/value.hh b/src/libexpr/value.hh
index 3d07c3198..9de0ece68 100644
--- a/src/libexpr/value.hh
+++ b/src/libexpr/value.hh
@@ -3,6 +3,7 @@
 #include <cassert>
 
 #include "symbol-table.hh"
+#include "input-accessor.hh"
 
 #if HAVE_BOEHMGC
 #include <gc/gc_allocator.h>
@@ -170,7 +171,11 @@ public:
             const char * * context; // must be in sorted order
         } string;
 
-        const char * path;
+        struct {
+            InputAccessor * accessor;
+            const char * path;
+        } _path;
+
         Bindings * attrs;
         struct {
             size_t size;
@@ -255,14 +260,7 @@ public:
         mkString(((const std::string &) s).c_str());
     }
 
-    inline void mkPath(const char * s)
-    {
-        clearValue();
-        internalType = tPath;
-        path = s;
-    }
-
-    void mkPath(std::string_view s);
+    void mkPath(const SourcePath & path);
 
     inline void mkNull()
     {
@@ -404,6 +402,12 @@ public:
         auto begin = listElems();
         return ConstListIterable { begin, begin + listSize() };
     }
+
+    SourcePath path() const
+    {
+        assert(internalType == tPath);
+        return SourcePath { .accessor = *_path.accessor, .path = _path.path };
+    }
 };
 
 
diff --git a/src/libfetchers/input-accessor.cc b/src/libfetchers/input-accessor.cc
index cf631be10..10a275857 100644
--- a/src/libfetchers/input-accessor.cc
+++ b/src/libfetchers/input-accessor.cc
@@ -216,9 +216,14 @@ ref<FSInputAccessor> makeFSInputAccessor(
     return make_ref<FSInputAccessorImpl>(root, std::move(allowedPaths));
 }
 
+std::string SourcePath::to_string() const
+{
+    return path; // FIXME
+}
+
 std::ostream & operator << (std::ostream & str, const SourcePath & path)
 {
-    str << path.path; // FIXME
+    str << path.to_string();
     return str;
 }
 
diff --git a/src/libfetchers/input-accessor.hh b/src/libfetchers/input-accessor.hh
index f14312026..129c1f345 100644
--- a/src/libfetchers/input-accessor.hh
+++ b/src/libfetchers/input-accessor.hh
@@ -72,16 +72,26 @@ ref<InputAccessor> makePatchingInputAccessor(
 
 struct SourcePath
 {
-    ref<InputAccessor> accessor;
+    InputAccessor & accessor;
     Path path;
 
     std::string_view baseName() const;
 
     std::string readFile() const
-    { return accessor->readFile(path); }
+    { return accessor.readFile(path); }
 
     bool pathExists() const
-    { return accessor->pathExists(path); }
+    { return accessor.pathExists(path); }
+
+    InputAccessor::DirEntries readDirectory() const
+    {  return accessor.readDirectory(path); }
+
+    void dumpPath(
+        Sink & sink,
+        PathFilter & filter = defaultPathFilter) const
+    { return accessor.dumpPath(path, sink, filter); }
+
+    std::string to_string() const;
 };
 
 std::ostream & operator << (std::ostream & str, const SourcePath & path);
diff --git a/src/nix/flake.cc b/src/nix/flake.cc
index 66e8295ad..f6ce12b4e 100644
--- a/src/nix/flake.cc
+++ b/src/nix/flake.cc
@@ -452,9 +452,7 @@ struct CmdFlakeCheck : FlakeCommand
                 if (auto attr = v.attrs->get(state->symbols.create("path"))) {
                     if (attr->name == state->symbols.create("path")) {
                         PathSet context;
-                        auto path = state->coerceToPath(*attr->pos, *attr->value, context);
-                        if (!store->isInStore(path))
-                            throw Error("template '%s' has a bad 'path' attribute");
+                        state->coerceToStorePath(*attr->pos, *attr->value, context);
                         // TODO: recursively check the flake in 'path'.
                     }
                 } else
diff --git a/src/nix/main.cc b/src/nix/main.cc
index 6198681e7..9db3e3494 100644
--- a/src/nix/main.cc
+++ b/src/nix/main.cc
@@ -178,6 +178,7 @@ static void showHelp(std::vector<std::string> subcommand, MultiCommand & topleve
         #include "generate-manpage.nix.gen.hh"
         , "/"), *vGenerateManpage);
 
+    // FIXME: use MemoryAccessor
     auto vUtils = state.allocValue();
     state.cacheFile(
         "/utils.nix", "/utils.nix",
diff --git a/src/nix/repl.cc b/src/nix/repl.cc
index 5ad85691b..17bfe2dde 100644
--- a/src/nix/repl.cc
+++ b/src/nix/repl.cc
@@ -772,7 +772,7 @@ std::ostream & NixRepl::printValue(std::ostream & str, Value & v, unsigned int m
         break;
 
     case nPath:
-        str << ANSI_GREEN << v.path << ANSI_NORMAL; // !!! escaping?
+        str << ANSI_GREEN << v.path().path << ANSI_NORMAL; // !!! escaping?
         break;
 
     case nNull: