Description:
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$_ SESSION don't registry variable from array and don't report error

Reproduce code:
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$pesquisa  = "SELECT indice FROM sica_cadastro WHERE login='$login'";
$resultado = mysql_query($pesquisa) or exit(mysql_error());
$dados     = mysql_fetch_assoc($resultado);
// it's not working
$_SESSION['s_indice'] = $dados['indice'];
// it don't work
// but don't report error


Expected result:
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registry a variable

Actual result:
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$pesquisa  = "SELECT indice FROM sica_cadastro WHERE login='$login'";
$resultado = mysql_query($pesquisa) or exit(mysql_error());
$dados     = mysql_fetch_assoc($resultado);
// it's working
$indice    = $dados['indice'];
$_SESSION['s_indice'] = $indice;