Fix clippy lints, impl treehash for slices

eth2/utils/cached_tree_hash/Cargo.toml

@@ -4,9 +4,6 @@ version = "0.1.0"
 authors = ["Paul Hauner <paul@paulhauner.com>"]
 edition = "2018"
 
-[profile.release]
-debug = true
-
 [[bench]]
 name = "benches"
 harness = false

eth2/utils/cached_tree_hash/examples/8k_hashes_standard.rs

@@ -1,4 +1,3 @@
-use cached_tree_hash::TreeHashCache;
 use ethereum_types::H256 as Hash256;
 use tree_hash::TreeHash;
 

eth2/utils/cached_tree_hash/src/impls/vec.rs

@@ -2,7 +2,9 @@ use super::*;
 use crate::btree_overlay::LeafNode;
 use crate::merkleize::{merkleize, num_sanitized_leaves, sanitise_bytes};
 
-impl<T> CachedTreeHash for Vec<T>
+macro_rules! impl_for_list {
+    ($type: ty) => {
+        impl<T> CachedTreeHash for $type
         where
             T: CachedTreeHash + TreeHash,
         {
@@ -28,7 +30,7 @@ where
                 cache.chunk_index += 1;
 
                 // Update the cache, returning the new overlay.
-        let new_overlay = update_tree_hash_cache(self, cache)?;
+                let new_overlay = update_tree_hash_cache(&self, cache)?;
 
                 // Mix in length
                 cache.mix_in_length(new_overlay.chunk_range(), self.len())?;
@@ -39,9 +41,14 @@ where
                 Ok(())
             }
         }
+    };
+}
+
+impl_for_list!(Vec<T>);
+impl_for_list!(&[T]);
 
 pub fn new_tree_hash_cache<T: CachedTreeHash>(
-    vec: &Vec<T>,
+    vec: &[T],
     depth: usize,
 ) -> Result<(TreeHashCache, BTreeSchema), Error> {
     let schema = vec.tree_hash_cache_schema(depth);
@@ -58,7 +65,7 @@ pub fn new_tree_hash_cache<T: CachedTreeHash>(
                 .map(|item| TreeHashCache::new(item, depth + 1))
                 .collect::<Result<Vec<TreeHashCache>, _>>()?;
 
-            TreeHashCache::from_leaves_and_subtrees(vec, subtrees, depth)
+            TreeHashCache::from_leaves_and_subtrees(&vec, subtrees, depth)
         }
     }?;
 
@@ -91,11 +98,11 @@ pub fn produce_schema<T: CachedTreeHash>(vec: &[T], depth: usize) -> BTreeSchema
 
 #[allow(clippy::range_plus_one)] // Minor readability lint requiring structural changes; not worth it.
 pub fn update_tree_hash_cache<T: CachedTreeHash>(
-    vec: &Vec<T>,
+    vec: &[T],
     cache: &mut TreeHashCache,
 ) -> Result<BTreeOverlay, Error> {
     let old_overlay = cache.get_overlay(cache.schema_index, cache.chunk_index)?;
-    let new_overlay = BTreeOverlay::new(vec, cache.chunk_index, old_overlay.depth);
+    let new_overlay = BTreeOverlay::new(&vec, cache.chunk_index, old_overlay.depth);
 
     cache.replace_overlay(cache.schema_index, cache.chunk_index, new_overlay.clone())?;
 

eth2/utils/tree_hash/src/impls.rs

@@ -87,7 +87,9 @@ impl TreeHash for H256 {
     }
 }
 
-impl<T> TreeHash for Vec<T>
+macro_rules! impl_for_list {
+    ($type: ty) => {
+        impl<T> TreeHash for $type
         where
             T: TreeHash,
         {
@@ -111,6 +113,11 @@ where
                 hash(&root_and_len)
             }
         }
+    };
+}
+
+impl_for_list!(Vec<T>);
+impl_for_list!(&[T]);
 
 pub fn vec_tree_hash_root<T>(vec: &[T]) -> Vec<u8>
 where