diff --git a/src/common/pl/plpgsql/src/gram.y b/src/common/pl/plpgsql/src/gram.y
index 2a798b661..30e72e893 100755
--- a/src/common/pl/plpgsql/src/gram.y
+++ b/src/common/pl/plpgsql/src/gram.y
@@ -3465,7 +3465,7 @@ stmt_while		: opt_block_label K_WHILE expr_until_while_loop loop_body
                         {
                             if($3.endtoken != K_LOOP)
                                  ereport(ERROR,
-                                    (errcode(ERRCODE_SYNTAX_ERROR), errmsg("'while-do' is only supported in database which dbcompatibility='B'."), parser_errposition(@2)));
+                                    (errcode(ERRCODE_SYNTAX_ERROR), errmsg("while-loop syntax is mixed with while-do syntax"), parser_errposition(@2)));
                         }
 
                         PLpgSQL_stmt_while *newp;
diff --git a/src/test/regress/expected/b_compatibility.out b/src/test/regress/expected/b_compatibility.out
index e4ec8c110..718045ebd 100644
--- a/src/test/regress/expected/b_compatibility.out
+++ b/src/test/regress/expected/b_compatibility.out
@@ -2404,7 +2404,7 @@ BEGIN
   end loop;
 end; 
 /
-ERROR:  'while-do' is only supported in database which dbcompatibility='B'.
+ERROR:  while-loop syntax is mixed with while-do syntax
 LINE 3:   while _i < 10 do
           ^
 QUERY:  declare _i integer = 0;