diff --git a/lix/libexpr/eval.cc b/lix/libexpr/eval.cc
index 88231e4b4..202273202 100644
--- a/lix/libexpr/eval.cc
+++ b/lix/libexpr/eval.cc
@@ -107,6 +107,8 @@ std::string showType(const Value & v)
             switch (v.auxiliary()->type) {
             case Value::Acb::tExternal:
                 return v.external()->showType();
+            case Value::Acb::tFloat:
+                return std::string(showType(v.type()));
             }
 #pragma GCC diagnostic pop
         case tThunk: return v.isBlackhole() ? "a black hole" : "a thunk";
diff --git a/lix/libexpr/nixexpr.hh b/lix/libexpr/nixexpr.hh
index 54be8ed95..009c5767b 100644
--- a/lix/libexpr/nixexpr.hh
+++ b/lix/libexpr/nixexpr.hh
@@ -177,14 +177,27 @@ protected:
 public:
 
     ExprLiteral(const PosIdx pos, NewValueAs::integer_t, NixInt n) : Expr(pos) { v.mkInt(n); };
-    ExprLiteral(const PosIdx pos, NewValueAs::integer_t, NixInt::Inner n) : Expr(pos) { v.mkInt(n); };
-    ExprLiteral(const PosIdx pos, NewValueAs::floating_t, NixFloat nf) : Expr(pos) { v.mkFloat(nf); };
+    ExprLiteral(const PosIdx pos, NewValueAs::integer_t, NixInt::Inner n) : Expr(pos)
+    {
+        v.mkInt(n);
+    }
     Value * maybeThunk(EvalState & state, Env & env) override;
     JSON toJSON(const SymbolTable & symbols) const override;
     void eval(EvalState & state, Env & env, Value & v) override;
     void accept(ExprVisitor & ev, std::unique_ptr<Expr> & ptr) override { ev.visit(*this, ptr); }
 };
 
+struct ExprFloat : ExprLiteral
+{
+    Value::Float f;
+    ExprFloat(const PosIdx pos, NewValueAs::floating_t, double f)
+        : ExprLiteral(pos)
+        , f{{Value::Acb::tFloat}, f}
+    {
+        v = Value(this->f);
+    }
+};
+
 struct ExprString : ExprLiteral
 {
     std::string s;
diff --git a/lix/libexpr/parser/parser-impl1.inc.cc b/lix/libexpr/parser/parser-impl1.inc.cc
index d698daddb..487b5ff96 100644
--- a/lix/libexpr/parser/parser-impl1.inc.cc
+++ b/lix/libexpr/parser/parser-impl1.inc.cc
@@ -542,7 +542,7 @@ template<> struct BuildAST<grammar::v1::expr::float_> {
                 });
             }
         }();
-        s.emplaceExpr<ExprLiteral>(ps.at(in), NewValueAs::floating, v);
+        s.emplaceExpr<ExprFloat>(ps.at(in), NewValueAs::floating, v);
     }
 };
 
diff --git a/lix/libexpr/value.hh b/lix/libexpr/value.hh
index f4d46973d..7bccb785b 100644
--- a/lix/libexpr/value.hh
+++ b/lix/libexpr/value.hh
@@ -34,7 +34,6 @@ typedef enum {
     tLambda,
     tPrimOp,
     tAuxiliary,
-    tFloat
 } InternalType;
 
 /**
@@ -259,11 +258,13 @@ public:
 
     /// Constructs a nix language value of type "float", with the floating
     /// point value of @ref f.
-    Value(floating_t, NixFloat f)
-        : internalType(tFloat)
-        , _fpoint(f)
-        , _float_pad(0)
-    { }
+    Value(floating_t, NixFloat f) : internalType(tAuxiliary), _aux_pad(0)
+    {
+        auto fp = gcAllocType<Float>();
+        fp->type = Acb::tFloat;
+        fp->value = f;
+        _auxiliary = fp;
+    }
 
     /// Constructs a nix language value of type "bool", with the boolean
     /// value of @ref b.
@@ -638,12 +639,17 @@ public:
     {
         enum {
             tExternal,
+            tFloat,
         } type;
     };
     struct External : Acb
     {
         ExternalValueBase * external;
     };
+    struct Float : Acb
+    {
+        NixFloat value;
+    };
 
     union
     {
@@ -688,10 +694,6 @@ public:
             const Acb * _auxiliary;
             uintptr_t _aux_pad;
         };
-        struct {
-            NixFloat _fpoint;
-            uintptr_t _float_pad;
-        };
     };
 
     /**
@@ -719,8 +721,9 @@ public:
                 switch (_auxiliary->type) {
                 case Acb::tExternal:
                     return nExternal;
+                case Acb::tFloat:
+                    return nFloat;
                 }
-            case tFloat: return nFloat;
             case tThunk:
                 return nThunk;
             case tApp:
@@ -834,9 +837,7 @@ public:
 
     inline void mkFloat(NixFloat n)
     {
-        clearValue();
-        internalType = tFloat;
-        _fpoint = n;
+        *this = {NewValueAs::floating, n};
     }
 
     bool isList() const
@@ -954,7 +955,8 @@ public:
 
     NixFloat fpoint() const
     {
-        return _fpoint;
+        assert(internalType == tAuxiliary && _auxiliary->type == Acb::tFloat);
+        return static_cast<const Float *>(_auxiliary)->value;
     }
 
     const Acb * auxiliary() const