The precedence table gave "." the same precedence as "+" and "-", which is
the PHP 7 ordering. PHP 8.0 lowered "." below the arithmetic and shift
operators, so printing ('abc' . 1) + 2 produced 'abc' . 1 + 2, which PHP 8
reparses as 'abc' . (1 + 2). The same applied to "-", "<<" and ">>".
The printer already targets a specific PHP version and already varies
parenthesization by version, so select the concatenation precedence the same
way: for a target of PHP 8.0 or newer, place "." between the shift operators
and the pipe operator, matching the PHP8 block of grammar/php.y. Targets below
8.0 keep the PHP 7 table, which is correct for them and produces unchanged
output.
Fixes#1041
dualfroz
upstream