Yield operator precedence
-----
<?php

function gen() {
    yield "a" . "b";
    yield "a" or die;
    yield "k" => "a" . "b";
    yield "k" => "a" or die;
    var_dump([yield "k" => "a" . "b"]);
    yield yield "k1" => yield "k2" => "a" . "b";
    yield yield "k1" => (yield "k2") => "a" . "b";
    var_dump([yield "k1" => yield "k2" => "a" . "b"]);
    var_dump([yield "k1" => (yield "k2") => "a" . "b"]);
}
-----
!!php7
array(
    0: Stmt_Function(
        byRef: false
        name: Identifier(
            name: gen
        )
        params: array(
        )
        returnType: null
        stmts: array(
            0: Stmt_Expression(
                expr: Expr_Yield(
                    key: null
                    value: Expr_BinaryOp_Concat(
                        left: Scalar_String(
                            value: a
                        )
                        right: Scalar_String(
                            value: b
                        )
                    )
                )
            )
            1: Stmt_Expression(
                expr: Expr_BinaryOp_LogicalOr(
                    left: Expr_Yield(
                        key: null
                        value: Scalar_String(
                            value: a
                        )
                    )
                    right: Expr_Exit(
                        expr: null
                    )
                )
            )
            2: Stmt_Expression(
                expr: Expr_Yield(
                    key: Scalar_String(
                        value: k
                    )
                    value: Expr_BinaryOp_Concat(
                        left: Scalar_String(
                            value: a
                        )
                        right: Scalar_String(
                            value: b
                        )
                    )
                )
            )
            3: Stmt_Expression(
                expr: Expr_BinaryOp_LogicalOr(
                    left: Expr_Yield(
                        key: Scalar_String(
                            value: k
                        )
                        value: Scalar_String(
                            value: a
                        )
                    )
                    right: Expr_Exit(
                        expr: null
                    )
                )
            )
            4: Stmt_Expression(
                expr: Expr_FuncCall(
                    name: Name(
                        parts: array(
                            0: var_dump
                        )
                    )
                    args: array(
                        0: Arg(
                            value: Expr_Array(
                                items: array(
                                    0: Expr_ArrayItem(
                                        key: null
                                        value: Expr_Yield(
                                            key: Scalar_String(
                                                value: k
                                            )
                                            value: Expr_BinaryOp_Concat(
                                                left: Scalar_String(
                                                    value: a
                                                )
                                                right: Scalar_String(
                                                    value: b
                                                )
                                            )
                                        )
                                        byRef: false
                                        unpack: false
                                    )
                                )
                            )
                            byRef: false
                            unpack: false
                        )
                    )
                )
            )
            5: Stmt_Expression(
                expr: Expr_Yield(
                    key: null
                    value: Expr_Yield(
                        key: Scalar_String(
                            value: k1
                        )
                        value: Expr_Yield(
                            key: Scalar_String(
                                value: k2
                            )
                            value: Expr_BinaryOp_Concat(
                                left: Scalar_String(
                                    value: a
                                )
                                right: Scalar_String(
                                    value: b
                                )
                            )
                        )
                    )
                )
            )
            6: Stmt_Expression(
                expr: Expr_Yield(
                    key: Expr_Yield(
                        key: Scalar_String(
                            value: k1
                        )
                        value: Expr_Yield(
                            key: null
                            value: Scalar_String(
                                value: k2
                            )
                        )
                    )
                    value: Expr_BinaryOp_Concat(
                        left: Scalar_String(
                            value: a
                        )
                        right: Scalar_String(
                            value: b
                        )
                    )
                )
            )
            7: Stmt_Expression(
                expr: Expr_FuncCall(
                    name: Name(
                        parts: array(
                            0: var_dump
                        )
                    )
                    args: array(
                        0: Arg(
                            value: Expr_Array(
                                items: array(
                                    0: Expr_ArrayItem(
                                        key: null
                                        value: Expr_Yield(
                                            key: Scalar_String(
                                                value: k1
                                            )
                                            value: Expr_Yield(
                                                key: Scalar_String(
                                                    value: k2
                                                )
                                                value: Expr_BinaryOp_Concat(
                                                    left: Scalar_String(
                                                        value: a
                                                    )
                                                    right: Scalar_String(
                                                        value: b
                                                    )
                                                )
                                            )
                                        )
                                        byRef: false
                                        unpack: false
                                    )
                                )
                            )
                            byRef: false
                            unpack: false
                        )
                    )
                )
            )
            8: Stmt_Expression(
                expr: Expr_FuncCall(
                    name: Name(
                        parts: array(
                            0: var_dump
                        )
                    )
                    args: array(
                        0: Arg(
                            value: Expr_Array(
                                items: array(
                                    0: Expr_ArrayItem(
                                        key: Expr_Yield(
                                            key: Scalar_String(
                                                value: k1
                                            )
                                            value: Expr_Yield(
                                                key: null
                                                value: Scalar_String(
                                                    value: k2
                                                )
                                            )
                                        )
                                        value: Expr_BinaryOp_Concat(
                                            left: Scalar_String(
                                                value: a
                                            )
                                            right: Scalar_String(
                                                value: b
                                            )
                                        )
                                        byRef: false
                                        unpack: false
                                    )
                                )
                            )
                            byRef: false
                            unpack: false
                        )
                    )
                )
            )
        )
    )
)