diff --git a/src/libcmd/command.cc b/src/libcmd/command.cc
index ee5102a6a..9cf2ff5e3 100644
--- a/src/libcmd/command.cc
+++ b/src/libcmd/command.cc
@@ -137,9 +137,10 @@ ref<EvalState> EvalCommand::getEvalState()
                 if (error)
                     printError("%s\n\n" ANSI_BOLD "Starting REPL to allow you to inspect the current state of the evaluator.\n" ANSI_NORMAL, error->what());
 
-                if (expr.staticEnv) {
-                    auto vm = mapStaticEnvBindings(evalState.symbols, *expr.staticEnv.get(), env);
-                    runRepl(*const_cast<EvalState*>(&evalState), *vm);
+                auto se = evalState->getStaticEnv(expr);
+                if (se) {
+                    auto vm = mapStaticEnvBindings(evalState->symbols, *se.get(), env);
+                    runRepl(evalState, *vm);
                 }
             };
     }
diff --git a/src/libcmd/repl.cc b/src/libcmd/repl.cc
index cb5d5bb34..5b17f2fb2 100644
--- a/src/libcmd/repl.cc
+++ b/src/libcmd/repl.cc
@@ -441,8 +441,9 @@ void NixRepl::loadDebugTraceEnv(DebugTrace & dt)
 {
     initEnv();
 
-    if (dt.expr.staticEnv) {
-        auto vm = mapStaticEnvBindings(state->symbols, *dt.expr.staticEnv.get(), dt.env);
+    auto se = state->getStaticEnv(dt.expr);
+    if (se) {
+        auto vm = mapStaticEnvBindings(state->symbols, *se.get(), dt.env);
 
         // add staticenv vars.
         for (auto & [name, value] : *(vm.get()))
@@ -516,7 +517,7 @@ bool NixRepl::processLine(std::string line)
     else if (debuggerHook && (command == ":env")) {
         for (const auto & [idx, i] : enumerate(state->debugTraces)) {
             if (idx == debugTraceIndex) {
-                printEnvBindings(state->symbols, i.expr, i.env);
+                printEnvBindings(*state, i.expr, i.env);
                 break;
             }
         }
@@ -533,7 +534,7 @@ bool NixRepl::processLine(std::string line)
                  std::cout << "\n" << ANSI_BLUE << idx << ANSI_NORMAL << ": ";
                  showDebugTrace(std::cout, state->positions, i);
                  std::cout << std::endl;
-                 printEnvBindings(state->symbols, i.expr, i.env);
+                 printEnvBindings(*state, i.expr, i.env);
                  loadDebugTraceEnv(i);
                  break;
              }
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 3c998f7b6..bd1cbaab5 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -772,12 +772,12 @@ void printEnvBindings(const SymbolTable & st, const StaticEnv & se, const Env &
     }
 }
 
-// TODO: add accompanying env for With stuff.
-void printEnvBindings(const SymbolTable & st, const Expr & expr, const Env & env)
+void printEnvBindings(const EvalState &es, const Expr & expr, const Env & env)
 {
     // just print the names for now
-    if (expr.staticEnv)
-        printEnvBindings(st, *expr.staticEnv.get(), env, 0);
+    auto se = es.getStaticEnv(expr);
+    if (se)
+        printEnvBindings(es.symbols, *se, env, 0);
 }
 
 void mapStaticEnvBindings(const SymbolTable & st, const StaticEnv & se, const Env & env, ValMap & vm)
diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 26717a6f8..5227c7ce1 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -25,7 +25,7 @@ enum RepairFlag : bool;
 
 typedef void (* PrimOpFun) (EvalState & state, const PosIdx pos, Value * * args, Value & v);
 
-void printEnvBindings(const SymbolTable & st, const Expr & expr, const Env & env);
+void printEnvBindings(const EvalState &es, const Expr & expr, const Env & env);
 void printEnvBindings(const SymbolTable & st, const StaticEnv & se, const Env & env, int lvl = 0);
 
 struct PrimOp
@@ -130,6 +130,16 @@ public:
     bool debugStop;
     bool debugQuit;
     std::list<DebugTrace> debugTraces;
+    std::map<const Expr*, const std::shared_ptr<const StaticEnv> > exprEnvs;
+    const std::shared_ptr<const StaticEnv>  getStaticEnv(const Expr &expr) const
+    {
+        auto i = exprEnvs.find(&expr);
+        if (i != exprEnvs.end()) 
+            return i->second;
+        else
+            return std::shared_ptr<const StaticEnv>();;
+    }
+
 
     template<class E>
     [[gnu::noinline, gnu::noreturn]]
diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc
index a7b7b8aad..cb5e1c3f2 100644
--- a/src/libexpr/nixexpr.cc
+++ b/src/libexpr/nixexpr.cc
@@ -296,38 +296,39 @@ std::string showAttrPath(const SymbolTable & symbols, const AttrPath & attrPath)
 
 /* Computing levels/displacements for variables. */
 
-void Expr::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void Expr::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     abort();
 }
 
-void ExprInt::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprInt::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;}
-
-void ExprFloat::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
-{
-    if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 }
 
-void ExprString::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprFloat::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 }
 
-void ExprPath::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprString::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 }
 
-void ExprVar::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprPath::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
+}
+
+void ExprVar::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+{
+    if (debuggerHook)
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     /* Check whether the variable appears in the environment.  If so,
        set its level and displacement. */
@@ -360,10 +361,10 @@ void ExprVar::bindVars(const EvalState & es, const std::shared_ptr<const StaticE
     this->level = withLevel;
 }
 
-void ExprSelect::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprSelect::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     e->bindVars(es, env);
     if (def) def->bindVars(es, env);
@@ -372,10 +373,10 @@ void ExprSelect::bindVars(const EvalState & es, const std::shared_ptr<const Stat
             i.expr->bindVars(es, env);
 }
 
-void ExprOpHasAttr::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprOpHasAttr::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     e->bindVars(es, env);
     for (auto & i : attrPath)
@@ -383,10 +384,10 @@ void ExprOpHasAttr::bindVars(const EvalState & es, const std::shared_ptr<const S
             i.expr->bindVars(es, env);
 }
 
-void ExprAttrs::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprAttrs::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     if (recursive) {
         auto newEnv = std::make_shared<StaticEnv>(false, env.get(), recursive ? attrs.size() : 0);
@@ -416,19 +417,19 @@ void ExprAttrs::bindVars(const EvalState & es, const std::shared_ptr<const Stati
     }
 }
 
-void ExprList::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprList::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     for (auto & i : elems)
         i->bindVars(es, env);
 }
 
-void ExprLambda::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprLambda::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     auto newEnv = std::make_shared<StaticEnv>(
         false, env.get(),
@@ -452,20 +453,20 @@ void ExprLambda::bindVars(const EvalState & es, const std::shared_ptr<const Stat
     body->bindVars(es, newEnv);
 }
 
-void ExprCall::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprCall::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     fun->bindVars(es, env);
     for (auto e : args)
         e->bindVars(es, env);
 }
 
-void ExprLet::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprLet::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     auto newEnv = std::make_shared<StaticEnv>(false, env.get(), attrs->attrs.size());
 
@@ -481,10 +482,10 @@ void ExprLet::bindVars(const EvalState & es, const std::shared_ptr<const StaticE
     body->bindVars(es, newEnv);
 }
 
-void ExprWith::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprWith::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     /* Does this `with' have an enclosing `with'?  If so, record its
        level so that `lookupVar' can look up variables in the previous
@@ -499,53 +500,53 @@ void ExprWith::bindVars(const EvalState & es, const std::shared_ptr<const Static
         }
 
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     attrs->bindVars(es, env);
     auto newEnv = std::make_shared<StaticEnv>(true, env.get());
     body->bindVars(es, newEnv);
 }
 
-void ExprIf::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprIf::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     cond->bindVars(es, env);
     then->bindVars(es, env);
     else_->bindVars(es, env);
 }
 
-void ExprAssert::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprAssert::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     cond->bindVars(es, env);
     body->bindVars(es, env);
 }
 
-void ExprOpNot::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprOpNot::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     e->bindVars(es, env);
 }
 
-void ExprConcatStrings::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprConcatStrings::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 
     for (auto & i : *this->es)
         i.second->bindVars(es, env);
 }
 
-void ExprPos::bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)
+void ExprPos::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
     if (debuggerHook)
-        staticEnv = env;
+        es.exprEnvs.insert(std::make_pair(this, env));
 }
 
 
diff --git a/src/libexpr/nixexpr.hh b/src/libexpr/nixexpr.hh
index 856676033..80b6afa3e 100644
--- a/src/libexpr/nixexpr.hh
+++ b/src/libexpr/nixexpr.hh
@@ -144,18 +144,17 @@ struct Expr
 {
     virtual ~Expr() { };
     virtual void show(const SymbolTable & symbols, std::ostream & str) const;
-    virtual void bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env);
+    virtual void bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env);
     virtual void eval(EvalState & state, Env & env, Value & v);
     virtual Value * maybeThunk(EvalState & state, Env & env);
     virtual void setName(Symbol name);
-    std::shared_ptr<const StaticEnv> staticEnv;
     virtual PosIdx getPos() const { return noPos; }
 };
 
 #define COMMON_METHODS \
     void show(const SymbolTable & symbols, std::ostream & str) const;    \
     void eval(EvalState & state, Env & env, Value & v); \
-    void bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env);
+    void bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env);
 
 struct ExprInt : Expr
 {
@@ -402,7 +401,7 @@ struct ExprOpNot : Expr
         { \
             str << "("; e1->show(symbols, str); str << " " s " "; e2->show(symbols, str); str << ")"; \
         } \
-        void bindVars(const EvalState & es, const std::shared_ptr<const StaticEnv> & env)    \
+        void bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)    \
         { \
             e1->bindVars(es, env); e2->bindVars(es, env);    \
         } \