diff --git a/src/libexpr/flake/flake.cc b/src/libexpr/flake/flake.cc
index 212eceeac..cb50bd013 100644
--- a/src/libexpr/flake/flake.cc
+++ b/src/libexpr/flake/flake.cc
@@ -254,10 +254,10 @@ static Flake getFlake(
 
     if (auto outputs = vInfo.attrs->get(sOutputs)) {
         expectType(state, tLambda, *outputs->value, *outputs->pos);
-        flake.vOutputs = outputs->value;
+        flake.vOutputs = allocRootValue(outputs->value);
 
-        if (flake.vOutputs->lambda.fun->matchAttrs) {
-            for (auto & formal : flake.vOutputs->lambda.fun->formals->formals) {
+        if ((*flake.vOutputs)->lambda.fun->matchAttrs) {
+            for (auto & formal : (*flake.vOutputs)->lambda.fun->formals->formals) {
                 if (formal.name != state.sSelf)
                     flake.inputs.emplace(formal.name, FlakeInput {
                         .ref = parseFlakeRef(formal.name)
@@ -613,16 +613,16 @@ void callFlake(EvalState & state,
 
     mkString(*vRootSubdir, lockedFlake.flake.lockedRef.subdir);
 
-    static Value * vCallFlake = nullptr;
+    static RootValue vCallFlake = nullptr;
 
     if (!vCallFlake) {
-        vCallFlake = state.allocValue();
+        vCallFlake = allocRootValue(state.allocValue());
         state.eval(state.parseExprFromString(
             #include "call-flake.nix.gen.hh"
-            , "/"), *vCallFlake);
+            , "/"), **vCallFlake);
     }
 
-    state.callFunction(*vCallFlake, *vLocks, *vTmp1, noPos);
+    state.callFunction(**vCallFlake, *vLocks, *vTmp1, noPos);
     state.callFunction(*vTmp1, *vRootSrc, *vTmp2, noPos);
     state.callFunction(*vTmp2, *vRootSubdir, vRes, noPos);
 }
diff --git a/src/libexpr/flake/flake.hh b/src/libexpr/flake/flake.hh
index 107498c1b..59a1adb3b 100644
--- a/src/libexpr/flake/flake.hh
+++ b/src/libexpr/flake/flake.hh
@@ -3,10 +3,10 @@
 #include "types.hh"
 #include "flakeref.hh"
 #include "lockfile.hh"
+#include "value.hh"
 
 namespace nix {
 
-struct Value;
 class EvalState;
 
 namespace fetchers { struct Tree; }
@@ -33,7 +33,7 @@ struct Flake
     std::optional<std::string> description;
     std::shared_ptr<const fetchers::Tree> sourceInfo;
     FlakeInputs inputs;
-    Value * vOutputs; // FIXME: gc
+    RootValue vOutputs;
     ~Flake();
 };
 
diff --git a/src/nix/installables.cc b/src/nix/installables.cc
index 99bbe9769..b8c75aaaf 100644
--- a/src/nix/installables.cc
+++ b/src/nix/installables.cc
@@ -239,18 +239,18 @@ struct InstallableExpr : InstallableValue
 
 struct InstallableAttrPath : InstallableValue
 {
-    Value * v;
+    RootValue v;
     std::string attrPath;
 
     InstallableAttrPath(SourceExprCommand & cmd, Value * v, const std::string & attrPath)
-        : InstallableValue(cmd), v(v), attrPath(attrPath)
+        : InstallableValue(cmd), v(allocRootValue(v)), attrPath(attrPath)
     { }
 
     std::string what() override { return attrPath; }
 
     std::pair<Value *, Pos> toValue(EvalState & state) override
     {
-        auto [vRes, pos] = findAlongAttrPath(state, attrPath, *cmd.getAutoArgs(state), *v);
+        auto [vRes, pos] = findAlongAttrPath(state, attrPath, *cmd.getAutoArgs(state), **v);
         state.forceValue(*vRes);
         return {vRes, pos};
     }