Arrow functions and and, or and xor, precedence differs from PHP

[sebsel]

I am here because I filed this bug at PHPStan: phpstan/phpstan#4824. It got labelled as 'easy fixes', so I looked into it. While I still don't understand that codebase at all, it seems to use PHP-Parser as parser, so the obvious place was to start here.

See also the PHPStan playground that I made for that issue: https://phpstan.org/r/35cfa468-01c1-4aab-b8e8-816b0b3a4b66

---

Basicly when I use an arrow function in combination with the and, or and xor keywords, PHP places the operator inside of the function, but PHP-Parser places the function inside of the operator...

So the example:

fn($a, $b) => $a and $b;
fn($a, $b) => $a && $b;

... is interpreted as:

// by PHP (it seems?)
fn($a, $b) => ($a and $b);
fn($a, $b) => ($a && $b);

// by PHP-Parser
(fn($a, $b) => $a) and $b;
fn($a, $b) => ($a && $b);

Current parsed result (I removed some properties to shorten the snippet):

array(
    0: Stmt_Expression(
        expr: Expr_BinaryOp_LogicalAnd(
            left: Expr_ArrowFunction(
                params: array(
                    0: Param(
                        var: Expr_Variable(
                            name: a
                        )
                    )
                    1: Param(
                        var: Expr_Variable(
                            name: b
                        )
                    )
                )
                expr: Expr_Variable(
                    name: a
                )
            )
            right: Expr_Variable(
                name: b
            )
        )
    )
    1: Stmt_Expression(
        expr: Expr_ArrowFunction(
            params: array(
                0: Param(
                    var: Expr_Variable(
                        name: a
                    )
                )
                1: Param(
                    var: Expr_Variable(
                        name: b
                    )
                )
            )
            expr: Expr_BinaryOp_BooleanAnd(
                left: Expr_Variable(
                    name: a
                )
                right: Expr_Variable(
                    name: b
                )
            )
        )
    )
)

Edit: cleaned up the example

[nikic]

Nice find!