问从“SymbolInfo*”转换为“YYSTYPE {aka int}”会丢失精度

EN

<some include files....>
#include "SymbolInfo.h"
#include "y.tab.h"

using namespace std;

int line_count = 1;
int TOTAL_ERROR = 0;

extern SymbolTable symbolTable;
extern FILE *yyin,*yyout;
extern YYSTYPE yylval;

<further declarations...>

%%

"int"    {
            SymbolInfo* s = new SymbolInfo(string(yytext),"INT");
            yylval = (YYSTYPE)s;
            return INT;
         }

<more patterns....>

%%

#include "SymbolInfo.h"

int SymbolTable::id = 0;

#define YYSTYPE SymbolInfo*

Lexical Analyzer.l: In function ‘int yylex()’:
Lexical Analyzer.l:162:27: error: cast from ‘SymbolInfo*’ to ‘YYSTYPE {aka int}’ loses precision [-fpermissive]
         yylval = (YYSTYPE)res;
                       ^