Compilation failed: error[E0283]: type annotations needed

[vi]

error[E0283]: type annotations needed
   --> src/cargo/util/config/de.rs:530:63
    |
530 |                 seed.deserialize(Tuple2Deserializer(1i32, env.as_ref()))
    |                                                           ----^^^^^^--
    |                                                           |   |
    |                                                           |   cannot infer type for type parameter `T` declared on the trait `AsRef`
    |                                                           this method call resolves to `&T`
    |
    = note: multiple `impl`s satisfying `std::string::String: AsRef<_>` found in the following crates: `alloc`, `std`:
            - impl AsRef<OsStr> for std::string::String;
            - impl AsRef<[u8]> for std::string::String;
            - impl AsRef<std::path::Path> for std::string::String;
            - impl AsRef<str> for std::string::String;

when following cargo install --force --git https://github.com/caeg-industries/cargo.git --branch subcrates --root ~/.rustup/toolchains/subcrate/ -- cargo line in the README.

Using rustc 1.60.0-nightly (0c292c966 2022-02-08) as primary toolchain. Updated to rustc 1.63.0-nightly (c06728704 2022-05-19) - still fails.