Parse error - Syntax Error GraphQL (57:49) Unexpected Name "null"

I faced this error during the benchmark of GraphQL parsers in the wild.

Query: https://github.com/StarpTech/graphql-parser-bench/blob/main/kitchen-sink.graphql
Code: https://github.com/StarpTech/graphql-parser-bench/tree/main/go-graphql

```
2021/08/15 11:19:12 Syntax Error GraphQL (57:49) Unexpected Name "null"

56: {
57: unnamed(truthy: true, falsey: false, nullish: null),
^
58: query
```