every time i lex compile, i get a warning message says rule cannot be matched

Question

i get it in line 39 which is the one of operand

 %option noyywrap
%{
#include<stdlib.h>
#include<stdio.h>
#include "y.tab.h"
%}
chif [0-9]
let [a-z|A-Z]
entier {chif}+
id {let}(_?({let}|{chif})+)*
reel {chif}+,{chif}+
operand ({entier}|{id}|{reel})
%%
{id} {return(IDENT);}
{entier} {return(INT);}
{reel} {return(REEL);}
{operand} {return(OPR);}

. {yyerror();}
%%

i tried changing the rule operand ({entier}|{id}|{reel}) to make it more specific and it didn't work, i also tried to change the placement and still nothing