建筑鳍状肢合同

如何解决建筑鳍状肢合同

我正在学习本教程 https://substrate.dev/substrate-contracts-workshop/#/0/building-your-contract，但出现以下错误。有谁知道如何解决这个问题？

➜  flipper cargo +nightly contract build
 [1/5] Building cargo project
    Updating crates.io index
   Compiling flipper v0.1.0 (/tmp/cargo-contract_dLtaWE)
error[E0277]: the trait bound `__ink_ConstructordispatchEnum: parity_scale_codec::codec::WrapperTypeDecode` is not satisfied
   --> /home/bill/flipper/lib.rs:5:1
    |
5   | #[ink::contract]
    | ^^^^^^^^^^^^^^^^ the trait `parity_scale_codec::codec::WrapperTypeDecode` is not implemented for `__ink_ConstructordispatchEnum`
    | 
   ::: /home/bill/.cargo/registry/src/github.com-1ecc6299db9ec823/ink_env-3.0.0-rc3/src/api.rs:465:8
    |
465 |     T: scale::Decode,|        ------------- required by this bound in `decode_input`
    |
    = note: required because of the requirements on the impl of `parity_scale_codec::codec::Decode` for `__ink_ConstructordispatchEnum`
    = note: this error originates in an attribute macro (in Nightly builds,run with -Z macro-backtrace for more info)

error[E0277]: the trait bound `__ink_MessagedispatchEnum: parity_scale_codec::codec::WrapperTypeDecode` is not satisfied
   --> /home/bill/flipper/lib.rs:5:1
    |
5   | #[ink::contract]
    | ^^^^^^^^^^^^^^^^ the trait `parity_scale_codec::codec::WrapperTypeDecode` is not implemented for `__ink_MessagedispatchEnum`
    | 
   ::: /home/bill/.cargo/registry/src/github.com-1ecc6299db9ec823/ink_env-3.0.0-rc3/src/api.rs:465:8
    |
465 |     T: scale::Decode,|        ------------- required by this bound in `decode_input`
    |
    = note: required because of the requirements on the impl of `parity_scale_codec::codec::Decode` for `__ink_MessagedispatchEnum`
    = note: this error originates in an attribute macro (in Nightly builds,run with -Z macro-backtrace for more info)

error: aborting due to 2 prevIoUs errors

For more information about this error,try `rustc --explain E0277`.
error: Could not compile `flipper`

To learn more,run the command again with --verbose.
ERROR: `"/home/bill/.rustup/toolchains/nightly-x86_64-unkNown-linux-gnu/bin/cargo" "build" "--target=wasm32-unkNown-unkNown" "-Zbuild-std" "-Zbuild-std-features=panic_immediate_abort" "--no-default-features" "--release" "--target-dir=/home/bill/flipper/target"` Failed with exit code: Some(101)