diff --git a/NEWS b/NEWS
index 9880d609..3695b81d 100644
--- a/NEWS
+++ b/NEWS
@@ -4,7 +4,7 @@ GNU Bison NEWS
 
 ** Bug fixes
 
-  Bison 3.3 failed to generate parsers for grammars with unused non terminal
+  Bison 3.3 failed to generate parsers for grammars with unused nonterminal
   symbols.
 
 * Noteworthy changes in release 3.3.1 (2019-01-27) [stable]
diff --git a/src/reduce.c b/src/reduce.c
index b1815531..ff2f2325 100644
--- a/src/reduce.c
+++ b/src/reduce.c
@@ -295,7 +295,7 @@ nonterminals_reduce (void)
     free (symbols_sorted);
   }
 
-  /* Renumber non terminal numbers in the RHS of the rules.  LHS are
+  /* Update nonterminal numbers in the RHS of the rules.  LHS are
      pointers to the symbol structure, they don't need renumbering. */
   {
     for (rule_number r = 0; r < nrules; ++r)
diff --git a/src/reduce.h b/src/reduce.h
index a6b4946b..9814962d 100644
--- a/src/reduce.h
+++ b/src/reduce.h
@@ -33,7 +33,7 @@ bool reduce_nonterminal_useless_in_grammar (const sym_content *sym);
 void reduce_free (void);
 
 /** Map initial nterm numbers to the new ones.  Built by
- * reduce_grammar.  Size nvars.  */
+ * reduce_grammar.  Size nvars + nuseless_nonterminals.  */
 extern symbol_number *nterm_map;
 
 extern unsigned nuseless_nonterminals;