diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 6d445fd96..afa864730 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -2506,6 +2506,7 @@ void EvalState::printStats()
             {"elements", nrValuesInEnvs},
             {"bytes", bEnvs},
         };
+        topObj["nrExprs"] = Expr::nrExprs;
         topObj["list"] = {
             {"elements", nrListElems},
             {"bytes", bLists},
diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc
index 4566a1388..22be8e68c 100644
--- a/src/libexpr/nixexpr.cc
+++ b/src/libexpr/nixexpr.cc
@@ -76,12 +76,12 @@ void Expr::show(const SymbolTable & symbols, std::ostream & str) const
 
 void ExprInt::show(const SymbolTable & symbols, std::ostream & str) const
 {
-    str << n;
+    str << v.integer;
 }
 
 void ExprFloat::show(const SymbolTable & symbols, std::ostream & str) const
 {
-    str << nf;
+    str << v.fpoint;
 }
 
 void ExprString::show(const SymbolTable & symbols, std::ostream & str) const
diff --git a/src/libexpr/nixexpr.hh b/src/libexpr/nixexpr.hh
index 944977e50..e766996c8 100644
--- a/src/libexpr/nixexpr.hh
+++ b/src/libexpr/nixexpr.hh
@@ -155,6 +155,10 @@ std::string showAttrPath(const SymbolTable & symbols, const AttrPath & attrPath)
 
 struct Expr
 {
+    static unsigned long nrExprs;
+    Expr() {
+        nrExprs++;
+    }
     virtual ~Expr() { };
     virtual void show(const SymbolTable & symbols, std::ostream & str) const;
     virtual void bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env);
@@ -171,18 +175,16 @@ struct Expr
 
 struct ExprInt : Expr
 {
-    NixInt n;
     Value v;
-    ExprInt(NixInt n) : n(n) { v.mkInt(n); };
+    ExprInt(NixInt n) { v.mkInt(n); };
     Value * maybeThunk(EvalState & state, Env & env) override;
     COMMON_METHODS
 };
 
 struct ExprFloat : Expr
 {
-    NixFloat nf;
     Value v;
-    ExprFloat(NixFloat nf) : nf(nf) { v.mkFloat(nf); };
+    ExprFloat(NixFloat nf) { v.mkFloat(nf); };
     Value * maybeThunk(EvalState & state, Env & env) override;
     COMMON_METHODS
 };
diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y
index 792f51fde..a3d3c7041 100644
--- a/src/libexpr/parser.y
+++ b/src/libexpr/parser.y
@@ -653,6 +653,7 @@ formal
 
 namespace nix {
 
+unsigned long Expr::nrExprs = 0;
 
 Expr * EvalState::parse(
     char * text,