diff --git a/libinterp/corefcn/fcn-info.cc b/libinterp/corefcn/fcn-info.cc
--- a/libinterp/corefcn/fcn-info.cc
+++ b/libinterp/corefcn/fcn-info.cc
@@ -377,6 +377,12 @@ namespace octave
     octave_user_function *current_fcn
       = search_scope ? search_scope.function () : nullptr;
 
+    if (search_scope.is_deleted () && current_fcn)
+      {
+        std::string nm = search_scope.name ();
+        error ("scope '%s' was deleted but current_fcn is valid?", nm.c_str ());
+      }
+
     // Subfunction.  I think it only makes sense to check for
     // subfunctions if we are currently executing a function defined
     // from a .m file.
diff --git a/libinterp/corefcn/symscope.h b/libinterp/corefcn/symscope.h
--- a/libinterp/corefcn/symscope.h
+++ b/libinterp/corefcn/symscope.h
@@ -67,7 +67,7 @@ namespace octave
       : m_name (name), m_symbols (), m_subfunctions (),
         m_persistent_values (), m_fcn (nullptr), m_parent (),
         m_primary_parent (), m_children (), m_nesting_depth (0),
-        m_is_static (false)
+        m_is_static (false), m_deleted (false)
     {
       // All scopes have ans as the first symbol, initially undefined.
 
@@ -102,6 +102,10 @@ namespace octave
 
     void mark_static (void) { m_is_static = true; }
 
+    bool is_deleted (void) const { return m_deleted; }
+
+    void mark_deleted (void) { m_deleted = true; }
+
     std::shared_ptr<symbol_scope_rep> parent_scope_rep (void) const
     {
       return m_parent.lock ();
@@ -131,6 +135,7 @@ namespace octave
       new_sid->m_children = m_children;
       new_sid->m_nesting_depth = m_nesting_depth;
       new_sid->m_is_static = m_is_static;
+      new_sid->m_deleted = m_deleted;
 
       return new_sid;
     }
@@ -244,7 +249,10 @@ namespace octave
 
     void cache_name (const std::string& name) { m_name = name; }
 
-    octave_user_function *function (void) const { return m_fcn; }
+    octave_user_function *function (void) const
+    {
+      return m_deleted ? nullptr : m_fcn;
+    }
 
     void set_function (octave_user_function *fcn) { m_fcn = fcn; }
 
@@ -320,6 +328,11 @@ namespace octave
     //! If true then no variables can be added.
 
     bool m_is_static;
+
+    //! If true then this scope is no longer valid, most likely because
+    //! function containing it was deleted.
+
+    bool m_deleted;
   };
 
   class symbol_scope
@@ -395,6 +408,17 @@ namespace octave
         m_rep->mark_static ();
     }
 
+    bool is_deleted (void) const
+    {
+      return m_rep ? m_rep->is_deleted () : false;
+    }
+
+    void mark_deleted (void)
+    {
+      if (m_rep)
+        m_rep->mark_deleted ();
+    }
+
     std::shared_ptr<symbol_scope_rep> parent_scope (void) const
     {
       return m_rep ? m_rep->parent_scope_rep () : nullptr;
diff --git a/libinterp/octave-value/ov-usr-fcn.cc b/libinterp/octave-value/ov-usr-fcn.cc
--- a/libinterp/octave-value/ov-usr-fcn.cc
+++ b/libinterp/octave-value/ov-usr-fcn.cc
@@ -64,6 +64,8 @@ static bool Voptimize_subsasgn_calls = t
 
 octave_user_code::~octave_user_code (void)
 {
+  m_scope.mark_deleted ();
+
   // FIXME: shouldn't this happen automatically when deleting cmd_list?
   if (cmd_list)
     cmd_list->remove_all_breakpoints (file_name);