fixes

frame/beefy-mmr/primitives/src/lib.rs

@@ -25,20 +25,17 @@
 //! compilation targets.
 //!
 //! Merkle Tree is constructed from arbitrary-length leaves, that are initially hashed using the
-//! same [Hasher] as the inner nodes.
+//! same hasher as the inner nodes.
 //! Inner nodes are created by concatenating child hashes and hashing again. The implementation
 //! does not perform any sorting of the input data (leaves) nor when inner nodes are created.
 //!
 //! If the number of leaves is not even, last leave (hash of) is promoted to the upper layer.
 
-#[cfg(not(feature = "std"))]
-extern crate alloc;
-#[cfg(not(feature = "std"))]
-use alloc::vec::Vec;
+pub use sp_runtime::traits::Keccak256;
+use sp_runtime::{app_crypto::sp_core, sp_std, traits::Hash as HashT};
+use sp_std::{vec, vec::Vec};
 
 use beefy_primitives::mmr::{BeefyAuthoritySet, BeefyNextAuthoritySet};
-pub use sp_runtime::traits::Keccak256;
-use sp_runtime::{app_crypto::sp_core, traits::Hash as HashT};
 
 /// Construct a root hash of a Binary Merkle Tree created from given leaves.
 ///