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: gen
        params: array(
        )
        returnType: null
        stmts: array(
            0: Expr_Yield(
                key: null
                value: Expr_BinaryOp_Concat(
                    left: Scalar_String(
                        value: a
                    )
                    right: Scalar_String(
                        value: b
                    )
                )
            )
            1: Expr_BinaryOp_LogicalOr(
                left: Expr_Yield(
                    key: null
                    value: Scalar_String(
                        value: a
                    )
                )
                right: Expr_Exit(
                    expr: null
                )
            )
            2: Expr_Yield(
                key: Scalar_String(
                    value: k
                )
                value: Expr_BinaryOp_Concat(
                    left: Scalar_String(
                        value: a
                    )
                    right: Scalar_String(
                        value: b
                    )
                )
            )
            3: Expr_BinaryOp_LogicalOr(
                left: Expr_Yield(
                    key: Scalar_String(
                        value: k
                    )
                    value: Scalar_String(
                        value: a
                    )
                )
                right: Expr_Exit(
                    expr: null
                )
            )
            4: 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
                                )
                            )
                        )
                        byRef: false
                        unpack: false
                    )
                )
            )
            5: 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: 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: 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
                                )
                            )
                        )
                        byRef: false
                        unpack: false
                    )
                )
            )
            8: 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
                                )
                            )
                        )
                        byRef: false
                        unpack: false
                    )
                )
            )
        )
    )
)