yysyntax_error (char *yyresult, int yystate, int yychar)
{
  int yyn = yypact[yystate];

  if (! (YYPACT_NINF < yyn && yyn <= YYLAST))
    return 0;
  else
    {
      int yytype = YYTRANSLATE (yychar);
      YYSIZE_T yysize0 = yytnamerr (0, yytname[yytype]);
      YYSIZE_T yysize = yysize0;
      YYSIZE_T yysize1;
      int yysize_overflow = 0;
      enum { YYERROR_VERBOSE_ARGS_MAXIMUM = 5 };
      char const *yyarg[YYERROR_VERBOSE_ARGS_MAXIMUM];
      int yyx;

# if 0
      /* This is so xgettext sees the translatable formats that are
	 constructed on the fly.  */
      YY_("syntax error, unexpected %s");
      YY_("syntax error, unexpected %s, expecting %s");
      YY_("syntax error, unexpected %s, expecting %s or %s");
      YY_("syntax error, unexpected %s, expecting %s or %s or %s");
      YY_("syntax error, unexpected %s, expecting %s or %s or %s or %s");
# endif
      char *yyfmt;
      char const *yyf;
      static char const yyunexpected[] = "syntax error, unexpected %s";
      static char const yyexpecting[] = ", expecting %s";
      static char const yyor[] = " or %s";
      char yyformat[sizeof yyunexpected
		    + sizeof yyexpecting - 1
		    + ((YYERROR_VERBOSE_ARGS_MAXIMUM - 2)
		       * (sizeof yyor - 1))];
      char const *yyprefix = yyexpecting;

      /* Start YYX at -YYN if negative to avoid negative indexes in
	 YYCHECK.  */
      int yyxbegin = yyn < 0 ? -yyn : 0;

      /* Stay within bounds of both yycheck and yytname.  */
      int yychecklim = YYLAST - yyn + 1;
      int yyxend = yychecklim < YYNTOKENS ? yychecklim : YYNTOKENS;
      int yycount = 1;

      yyarg[0] = yytname[yytype];
      yyfmt = yystpcpy (yyformat, yyunexpected);

      for (yyx = yyxbegin; yyx < yyxend; ++yyx)
	if (yycheck[yyx + yyn] == yyx && yyx != YYTERROR)
	  {
	    if (yycount == YYERROR_VERBOSE_ARGS_MAXIMUM)
	      {
		yycount = 1;
		yysize = yysize0;
		yyformat[sizeof yyunexpected - 1] = '\0';
		break;
	      }
	    yyarg[yycount++] = yytname[yyx];
	    yysize1 = yysize + yytnamerr (0, yytname[yyx]);
	    yysize_overflow |= (yysize1 < yysize);
	    yysize = yysize1;
	    yyfmt = yystpcpy (yyfmt, yyprefix);
	    yyprefix = yyor;
	  }

      yyf = YY_(yyformat);
      yysize1 = yysize + yystrlen (yyf);
      yysize_overflow |= (yysize1 < yysize);
      yysize = yysize1;

      if (yysize_overflow)
	return YYSIZE_MAXIMUM;

      if (yyresult)
	{
	  /* Avoid sprintf, as that infringes on the user's name space.
	     Don't have undefined behavior even if the translation
	     produced a string with the wrong number of "%s"s.  */
	  char *yyp = yyresult;
	  int yyi = 0;
	  while ((*yyp = *yyf) != '\0')
	    {
	      if (*yyp == '%' && yyf[1] == 's' && yyi < yycount)
		{
		  yyp += yytnamerr (yyp, yyarg[yyi++]);
		  yyf += 2;
		}
	      else
		{
		  yyp++;
		  yyf++;
		}
	    }
	}
      return yysize;
    }
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.