diff --git a/src/frontends/lean/builtin_cmds.cpp b/src/frontends/lean/builtin_cmds.cpp
index 0495719931..636011617c 100644
--- a/src/frontends/lean/builtin_cmds.cpp
+++ b/src/frontends/lean/builtin_cmds.cpp
@@ -336,10 +336,20 @@ struct stream_buffer_delete {
     }
 };
 
-flet<object *> lean_redirect_stdout(object * new_stdout);
+obj_res lean_redirect_stdout(obj_arg new_stdout);
 lean_object *  lean_io_wrap_handle(FILE *hfile);
 lean_object *& get_handle_current_stdout();
 
+struct redirect_helper {
+    object_ref m_old_fp;
+    redirect_helper(object_ref const & new_fp):
+        m_old_fp(lean_redirect_stdout(new_fp.to_obj_arg())) {
+    }
+    ~redirect_helper() {
+        lean_dec(lean_redirect_stdout(m_old_fp.to_obj_arg()));
+    }
+};
+
 static environment eval_cmd(parser & p) {
     transient_cmd_scope cmd_scope(p);
     auto pos = p.pos();
@@ -399,8 +409,8 @@ static environment eval_cmd(parser & p) {
     object_ref r;
 
     try {
-        object_ref newFP(lean_io_wrap_handle(fp));
-        flet<object *> oldFP(lean_redirect_stdout(newFP.raw()));
+        object_ref new_fp(lean_io_wrap_handle(fp));
+        redirect_helper helper(new_fp);
         if (p.profiling()) {
             timeit timer(out.get_text_stream().get_stream(), "eval time");
             r = object_ref(ir::run_boxed(new_env, fn_name, args.size(), &args[0]));
diff --git a/src/runtime/io.cpp b/src/runtime/io.cpp
index 3e41f16c0a..0fb292ec47 100644
--- a/src/runtime/io.cpp
+++ b/src/runtime/io.cpp
@@ -22,7 +22,6 @@ Author: Leonardo de Moura
 #include <cctype>
 #include <sys/stat.h>
 #include "util/io.h"
-#include "runtime/flet.h"
 #include "runtime/utf8.h"
 #include "runtime/object.h"
 #include "runtime/thread.h"
@@ -145,8 +144,10 @@ MK_THREAD_LOCAL_GET(object *, get_handle_current_stdout, g_handle_stdout);
 MK_THREAD_LOCAL_GET(object *, get_handle_current_stderr, g_handle_stderr);
 MK_THREAD_LOCAL_GET(object *, get_handle_current_stdin,  g_handle_stdin);
 
-flet<object *> lean_redirect_stdout(object * new_stdout) {
-    return flet<object *>(get_handle_current_stdout(), new_stdout);
+obj_res lean_redirect_stdout(obj_arg new_stdout) {
+    obj_res r = get_handle_current_stdout();
+    get_handle_current_stdout() = new_stdout;
+    return r;
 }
 
 /* getStdout : IO FS.Handle */