diff --git a/parse.y b/parse.y
index 4546195af..382f64cf2 100644
--- a/parse.y
+++ b/parse.y
@@ -2377,8 +2377,7 @@ module_item
 
   | K_task automatic_opt IDENTIFIER error K_endtask
       {
-	pform_pop_scope();
-	current_task = 0;
+	assert(current_task == 0);
 	delete[]$3;
       }
 
@@ -2418,8 +2417,7 @@ module_item
       }
   | K_function automatic_opt function_range_or_type_opt IDENTIFIER error K_endfunction
       {
-	pform_pop_scope();
-	current_task = 0;
+	assert(current_function == 0);
 	delete[]$4;
       }
 
diff --git a/pform.cc b/pform.cc
index 753626b0e..973f52c70 100644
--- a/pform.cc
+++ b/pform.cc
@@ -262,6 +262,7 @@ static LexicalScope* lexical_scope = 0;
 
 void pform_pop_scope()
 {
+      assert(lexical_scope);
       lexical_scope = lexical_scope->parent_scope();
 }