arithmetic operation overflow running Tendermint

[bgrieder]

I'm running:

• Which Parity version?: 1.9.4-beta
• Which operating system?: MacOS
• How installed?: via installer binaries
• Are you fully synchronized?: no
• Which network are you connected to?:custom
• Did you try to restart the node?: yes

Hello,

I am getting

Thread 'IO Worker #1' panicked at 'arithmetic operation overflow', cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/bigint-4.2.0/src/uint.rs:1227

When starting a node with Tendermint (single validator).
Same issue with Parity 1.7.2

My config.toml is

[parity]
chain = "resources/blockchain/genesis.json"
base_path = "/Volumes/EXT/Ethereum/networks/XYZ"
[network]
port = 30300
[rpc]
port = 8540
apis = ["web3", "eth", "net", "personal", "parity", "parity_set", "traces", "rpc", "parity_accounts"]
[ui]
port = 8180
[websockets]
port = 8450
[account]
password = ["resources/blockchain/node.pwds"]
[mining]
engine_signer = "0x527c6d143a090e9c1c18ae31bb05c717ca94e915"
reseal_on_txs = "none"

The genesis.json file is

{
    "name": "XYZ",
    "engine": {
        "tendermint": {
            "params": {
                "validators": {
                    "list": [
                        "0x527c6d143a090e9c1c18ae31bb05c717ca94e915"
                    ]
                },
                "blockReward": "0x0",
                "timeoutPropose": "0x01",
                "timeoutPrevote": "0x01",
                "timeoutPrecommit": "0x01",
                "timeoutCommit": "0x01"
            }
        }
    },
    "genesis": {
        "seal": {
            "tendermint": {
                "round": "0x0",
                "proposal": "0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
                "precommits": [
                    "0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
                ]
            }
        },
        "difficulty": "0x0",
        "gasLimit": "0x0"
    },
    "params": {
        "networkID": "0x4d4144",
        "maximumExtraDataSize": "0x20",
        "minGasLimit": "0x00",
        "gasLimitBoundDivisor": "0x400"
    },
    "accounts": {
        "0x0000000000000000000000000000000000000001": {
            "balance": "1",
            "builtin": {
                "name": "ecrecover",
                "pricing": {
                    "linear": {
                        "base": 3000,
                        "word": 0
                    }
                }
            }
        },
        "0x0000000000000000000000000000000000000002": {
            "balance": "1",
            "builtin": {
                "name": "sha256",
                "pricing": {
                    "linear": {
                        "base": 60,
                        "word": 12
                    }
                }
            }
        },
        "0x0000000000000000000000000000000000000003": {
            "balance": "1",
            "builtin": {
                "name": "ripemd160",
                "pricing": {
                    "linear": {
                        "base": 600,
                        "word": 120
                    }
                }
            }
        },
        "0x0000000000000000000000000000000000000004": {
            "balance": "1",
            "builtin": {
                "name": "identity",
                "pricing": {
                    "linear": {
                        "base": 15,
                        "word": 3
                    }
                }
            }
        },
        "0x00996ff81E27562fa27b94c3E931B5225B46da18": {
            "balance": "10000000000000000000000"
        }
    }
}

[bgrieder]

This seems to be happening when the validators list contains a single entry.
I would expect that it is possible to set-up a chain with a single validator