diff --git a/src/libcmd/installables.cc b/src/libcmd/installables.cc
index 3f6dfd592..635ce19b6 100644
--- a/src/libcmd/installables.cc
+++ b/src/libcmd/installables.cc
@@ -609,7 +609,7 @@ InstallableFlake::InstallableFlake(
         throw UsageError("'--arg' and '--argstr' are incompatible with flakes");
 }
 
-std::tuple<std::string, FlakeRef, InstallableValue::DerivationInfo, std::optional<NixInt>> InstallableFlake::toDerivation()
+std::tuple<std::string, FlakeRef, InstallableValue::DerivationInfo> InstallableFlake::toDerivation()
 {
     auto attr = getCursor(*state);
 
@@ -650,7 +650,7 @@ std::tuple<std::string, FlakeRef, InstallableValue::DerivationInfo, std::optiona
         .priority = priority,
     };
 
-    return {attrPath, getLockedFlake()->flake.lockedRef, std::move(drvInfo), priority};
+    return {attrPath, getLockedFlake()->flake.lockedRef, std::move(drvInfo)};
 }
 
 std::vector<InstallableValue::DerivationInfo> InstallableFlake::toDerivations()
diff --git a/src/libcmd/installables.hh b/src/libcmd/installables.hh
index d7b61f1b8..5d715210e 100644
--- a/src/libcmd/installables.hh
+++ b/src/libcmd/installables.hh
@@ -177,7 +177,7 @@ struct InstallableFlake : InstallableValue
 
     Value * getFlakeOutputs(EvalState & state, const flake::LockedFlake & lockedFlake);
 
-    std::tuple<std::string, FlakeRef, DerivationInfo, std::optional<NixInt>> toDerivation();
+    std::tuple<std::string, FlakeRef, DerivationInfo> toDerivation();
 
     std::vector<DerivationInfo> toDerivations() override;
 
diff --git a/src/libexpr/eval-cache.cc b/src/libexpr/eval-cache.cc
index bf811c8ed..6b3c27fd5 100644
--- a/src/libexpr/eval-cache.cc
+++ b/src/libexpr/eval-cache.cc
@@ -306,7 +306,7 @@ struct AttrDb
             case AttrType::Bool:
                 return {{rowId, queryAttribute.getInt(2) != 0}};
             case AttrType::Int:
-                return {{rowId, queryAttribute.getInt(2)}};
+                return {{rowId, (int_t) queryAttribute.getInt(2)}};
             case AttrType::ListOfStrings:
                 return {{rowId, tokenizeString<std::vector<std::string>>(queryAttribute.getStr(2), "\t")}};
             case AttrType::Missing:
@@ -649,9 +649,9 @@ NixInt AttrCursor::getInt()
         if (!cachedValue)
             cachedValue = root->db->getAttr(getKey());
         if (cachedValue && !std::get_if<placeholder_t>(&cachedValue->second)) {
-            if (auto i = std::get_if<NixInt>(&cachedValue->second)) {
+            if (auto i = std::get_if<int_t>(&cachedValue->second)) {
                 debug("using cached Integer attribute '%s'", getAttrPathStr());
-                return *i;
+                return (*i).x;
             } else
                 throw TypeError("'%s' is not an Integer", getAttrPathStr());
         }
diff --git a/src/libexpr/eval-cache.hh b/src/libexpr/eval-cache.hh
index ec255c60d..68b5952eb 100644
--- a/src/libexpr/eval-cache.hh
+++ b/src/libexpr/eval-cache.hh
@@ -52,6 +52,7 @@ struct placeholder_t {};
 struct missing_t {};
 struct misc_t {};
 struct failed_t {};
+struct int_t { NixInt x; int_t(NixInt x) : x(x) {}; };
 typedef uint64_t AttrId;
 typedef std::pair<AttrId, Symbol> AttrKey;
 typedef std::pair<std::string, NixStringContext> string_t;
@@ -64,7 +65,7 @@ typedef std::variant<
     misc_t,
     failed_t,
     bool,
-    NixInt,
+    int_t,
     std::vector<std::string>
     > AttrValue;
 
diff --git a/src/nix/profile.cc b/src/nix/profile.cc
index ca5041873..1aae347df 100644
--- a/src/nix/profile.cc
+++ b/src/nix/profile.cc
@@ -300,7 +300,7 @@ struct CmdProfileInstall : InstallablesCommand, MixDefaultProfile
 
             if (auto installable2 = std::dynamic_pointer_cast<InstallableFlake>(installable)) {
                 // FIXME: make build() return this?
-                auto [attrPath, resolvedRef, drv, priority] = installable2->toDerivation();
+                auto [attrPath, resolvedRef, drv] = installable2->toDerivation();
                 element.source = ProfileElementSource {
                     installable2->flakeRef,
                     resolvedRef,
@@ -475,7 +475,7 @@ struct CmdProfileUpgrade : virtual SourceExprCommand, MixDefaultProfile, MixProf
                     Strings{},
                     lockFlags);
 
-                auto [attrPath, resolvedRef, drv, priority] = installable->toDerivation();
+                auto [attrPath, resolvedRef, drv] = installable->toDerivation();
 
                 if (element.source->resolvedRef == resolvedRef) continue;