Build fails

[psacawa]

To reproduce:

git clone https://github.com/clearloop/leetcode-cli
cd leetcode-cli
cargo build

Note that this using the required toolchain nightly-2021-05-16 as confirmed with rustup.

Output:

error[E0599]: no function or associated item named `from_str` found for struct `proc_macro::Literal` in the current scope
   --> /home/psacawa/.cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-1.0.30/src/wrapper.rs:926:38
    |
926 |                 proc_macro::Literal::from_str(repr)
    |                                      ^^^^^^^^ function or associated item not found in `proc_macro::Literal`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0599`.
error: could not compile `proc-macro2`

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: build failed