diff --git a/src/env.cpp b/src/env.cpp
index cc27ad23d..6e7ad6f32 100644
--- a/src/env.cpp
+++ b/src/env.cpp
@@ -1054,8 +1054,7 @@ void env_stack_impl_t::set_in_node(const env_node_ref_t &node, const wcstring &k
 
     var = var.setting_vals(std::move(val))
               .setting_exports(res_exports)
-              .setting_pathvar(res_pathvar)
-              .setting_read_only(is_read_only(key));
+              .setting_pathvar(res_pathvar);
 
     // Perhaps mark that this node contains an exported variable, or shadows an exported variable.
     // If so regenerate the export list.
diff --git a/src/env.h b/src/env.h
index ecb528b57..bf24cbe9c 100644
--- a/src/env.h
+++ b/src/env.h
@@ -128,7 +128,6 @@ class env_var_t {
     env_var_t(const wchar_t *name, wcstring val) : env_var_t(std::move(val), flags_for(name)) {}
 
     bool empty() const { return vals_->empty() || (vals_->size() == 1 && vals_->front().empty()); }
-    bool read_only() const { return flags_ & flag_read_only; }
     bool exports() const { return flags_ & flag_export; }
     bool is_pathvar() const { return flags_ & flag_pathvar; }
     env_var_flags_t get_flags() const { return flags_; }
@@ -165,16 +164,6 @@ class env_var_t {
         return env_var_t{vals_, flags};
     }
 
-    env_var_t setting_read_only(bool read_only) const {
-        env_var_flags_t flags = flags_;
-        if (read_only) {
-            flags |= flag_read_only;
-        } else {
-            flags &= ~flag_read_only;
-        }
-        return env_var_t{vals_, flags};
-    }
-
     static env_var_flags_t flags_for(const wchar_t *name);
     static std::shared_ptr<const wcstring_list_t> empty_list();