Easy to reproduce:
### 20.3.13
```
SELECT 1
FORMAT JSON

{
        "meta":
        [
                {
                        "name": "1",
                        "type": "UInt8"
                }
        ],

        "data":
        [
                {
                        "1": 1
                }
        ],

        "rows": 1,

        "statistics":
        {
                "elapsed": 0.000203731,
                "rows_read": 1,
                "bytes_read": 1
        }
}
```

### 20.4.5
```
:) select 1 format JSON

SELECT 1
FORMAT JSON

{
        "meta":
        [
                {
                        "name": "1",
                        "type": "UInt8"
                }
        ],

        "data":
        [
                {
                        "1": 1
>>>>>>>> no closing bracket <<<<<<<<<<
        ],

        "rows": 1,

        "statistics":
        {
                "elapsed": 0.000771732,
                "rows_read": 1,
                "bytes_read": 1
        }
}
```
### master
```

SELECT 1
FORMAT JSON

{
        "meta":
        [
                {
                        "name": "1",
                        "type": "UInt8"
                }
        ],

        "data":
        [
                {
                        "1": 1
>>>>>>>> no closing bracket <<<<<<<<<<
        ],

        "rows": 1,

        "statistics":
        {
                "elapsed": 0.00103364,
                "rows_read": 1,
                "bytes_read": 1
        }
}

```

try
                {
                    std::stringstream dump_before_fuzz
                    fuzz_base->dumpTree(dump_before_fuzz)
                    auto base_before_fuzz = fuzz_base->formatForErrorMessage()
                    ast_to_process = fuzz_base->clone()
                    std::stringstream dump_of_cloned_ast
                    ast_to_process->dumpTree(dump_of_cloned_ast)
                    // Run the original query as ell.
                    
                    {
                        fuzzer.fuzzMain(ast_to_process)
                    
                    auto base_after_fuzz = fuzz_base->formatForErrorMessage()
                    // Debug AST cloning errors.
                     base_after_fuzz)
                    {
                        fprintf(stderr, "base before fuzz: %s\n"
                            "base after fuzz: %s\n", base_before_fuzz.c_str(),
                            base_after_fuzz.c_str())
                        fprintf(stderr, "dump before fuzz:\n%s\n",
                            dump_before_fuzz.str().c_str())
                        fprintf(stderr, "dump of cloned ast:\n%s\n",
                            dump_of_cloned_ast.str().c_str())
                        fprintf(stderr, "dump after fuzz:\n")
                        fuzz_base->dumpTree(std::cerr)
                        assert(false)
                    
                    auto fuzzed_text = ast_to_process->formatForErrorMessage()
                    if (fuzz_step > 0 && fuzzed_text == base_before_fuzz)