error: proc-macro derive panicked
  --> /Users/wuminzhe/.cargo/registry/src/github.com-1ecc6299db9ec823/hex-literal-0.1.4/src/lib.rs:38:1
   |
38 | / proc_macro_expr_decl! {
39 | |     /// Macro for converting hex string to byte array at compile time
40 | |     hex! => hex_impl
41 | | }
   | |_^
   |
   = help: message: assertion failed: `(left == right)`
             left: `Some("#[allow(unused,")`,
            right: `Some("#[allow(unused")`