cargo itself does need TOML support to build because cargo itself is a Rust crate [0]. But it's not a problem because you build a new version of cargo with an

cargo itself does need TOML support to build because cargo itself is a Rust crate [0]. But it's not a problem because you build a new version of cargo with an older version of cargo that of course can parse TOML. [0] https://github.com/rust-lang/cargo/blob/master/Cargo.toml https://github.com/rust-lang/cargo/blob/master/Cargo.toml