VARIATION RenameChain
input: {
    "pipeline": [
        {
            "$set": {
                "b": {
                    "$const": "a"
                }
            }
        },
        {
            "$set": {
                "c": "$b"
            }
        },
        {
            "$set": {
                "d": "$c"
            }
        },
        {
            "$set": {
                "e": "$d"
            }
        },
        {
            "$match": {
                "e": 1,
                "c": 1
            }
        }
    ]
}
output: {
    "$set:0": {
        "scope:0": {
            "exhaustiveScope": "scope:-1",
            "fields": {
                "<missing>:0": {
                    "declaringScope": "scope:0",
                    "dependencies": []
                },
                "b:1": {
                    "declaringScope": "scope:0",
                    "dependencies": []
                }
            }
        },
        "dependencies": []
    },
    "$set:1": {
        "scope:1": {
            "exhaustiveScope": "scope:-1",
            "fields": {
                "<missing>:2": {
                    "declaringScope": "scope:1",
                    "dependencies": []
                },
                "b:1": "b:1",
                "c:3": {
                    "declaringScope": "scope:1",
                    "dependencies": [
                        "b:1"
                    ]
                }
            }
        },
        "dependencies": [
            "b:1"
        ]
    },
    "$set:2": {
        "scope:2": {
            "exhaustiveScope": "scope:-1",
            "fields": {
                "<missing>:4": {
                    "declaringScope": "scope:2",
                    "dependencies": []
                },
                "b:1": "b:1",
                "c:3": "c:3",
                "d:5": {
                    "declaringScope": "scope:2",
                    "dependencies": [
                        "c:3"
                    ]
                }
            }
        },
        "dependencies": [
            "c:3"
        ]
    },
    "$set:3": {
        "scope:3": {
            "exhaustiveScope": "scope:-1",
            "fields": {
                "<missing>:6": {
                    "declaringScope": "scope:3",
                    "dependencies": []
                },
                "b:1": "b:1",
                "c:3": "c:3",
                "d:5": "d:5",
                "e:7": {
                    "declaringScope": "scope:3",
                    "dependencies": [
                        "d:5"
                    ]
                }
            }
        },
        "dependencies": [
            "d:5"
        ]
    },
    "$match:4": {
        "scope:3": "scope:3",
        "dependencies": [
            "c:3",
            "e:7"
        ]
    }
}

