diff --git a/rust-toolchain.toml b/rust-toolchain.toml
index e4205e80b..5d7f87026 100644
--- a/rust-toolchain.toml
+++ b/rust-toolchain.toml
@@ -1,6 +1,6 @@
 [toolchain]
 # The default profile includes rustc, rust-std, cargo, rust-docs, rustfmt and clippy.
 profile = "default"
-channel = "1.78"
+channel = "1.79"
 targets = [ "wasm32-unknown-unknown" ]
 
diff --git a/src/coprocessor/trie/mod.rs b/src/coprocessor/trie/mod.rs
index 61432daef..a5ea89fdb 100644
--- a/src/coprocessor/trie/mod.rs
+++ b/src/coprocessor/trie/mod.rs
@@ -785,8 +785,7 @@ impl<'a, F: LurkField, const ARITY: usize, const HEIGHT: usize> Trie<'a, F, ARIT
             .iter()
             .zip(preimage_path)
             .rev()
-            .enumerate()
-            .map(|(_i, (path_index, existing_preimage))| {
+            .map(|(path_index, existing_preimage)| {
                 let mut new_preimage = *existing_preimage;
                 new_preimage[*path_index] = value;
                 let new_hash = self.register_hash(new_preimage);