On a second though, the actual error seems to be elsewhere, so still can use proper indexing
[package]
name = "hedgewars-checker"
version = "1.0.0"
authors = ["Andrey Korotaev <a.korotaev@hedgewars.org>"]
edition = "2018"
[dependencies]
rust-ini = "0.13"
dirs = "1.0"
argparse = "0.2.2"
log = "0.4"
stderrlog = "0.4"
netbuf = "0.4"
tempfile = "3.0"
base64 = "0.9.3"