diff --git a/Dockerfile b/Dockerfile
index 64714452..b61e5d5c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM rust:1.65-buster as builder
+FROM rust:1.66-buster as builder
 WORKDIR /app
 ADD . /app
 ENV PATH=$PATH:/root/.cargo/bin
diff --git a/syncserver/src/db/mysql/batch.rs b/syncserver/src/db/mysql/batch.rs
index 4616c9b7..2bd9501d 100644
--- a/syncserver/src/db/mysql/batch.rs
+++ b/syncserver/src/db/mysql/batch.rs
@@ -139,13 +139,13 @@ pub fn commit(db: &MysqlDb, params: params::CommitBatch) -> Result<results::Comm
     let collection_id = db.get_collection_id(&params.collection)?;
     let timestamp = db.timestamp();
     sql_query(include_str!("batch_commit.sql"))
-        .bind::<BigInt, _>(user_id as i64)
+        .bind::<BigInt, _>(user_id)
         .bind::<Integer, _>(&collection_id)
         .bind::<BigInt, _>(&db.timestamp().as_i64())
         .bind::<BigInt, _>(&db.timestamp().as_i64())
         .bind::<BigInt, _>((MAXTTL as i64) * 1000) // XXX:
         .bind::<BigInt, _>(&batch_id)
-        .bind::<BigInt, _>(user_id as i64)
+        .bind::<BigInt, _>(user_id)
         .bind::<BigInt, _>(&db.timestamp().as_i64())
         .bind::<BigInt, _>(&db.timestamp().as_i64())
         .execute(&db.conn)?;
@@ -258,7 +258,7 @@ pub fn validate_batch_id(id: &str) -> Result<()> {
 }
 
 fn encode_id(id: i64) -> String {
-    base64::encode(&id.to_string())
+    base64::encode(id.to_string())
 }
 
 fn decode_id(id: &str) -> Result<i64> {
diff --git a/syncserver/src/db/mysql/models.rs b/syncserver/src/db/mysql/models.rs
index 8b7fb82f..1b61ec02 100644
--- a/syncserver/src/db/mysql/models.rs
+++ b/syncserver/src/db/mysql/models.rs
@@ -403,7 +403,7 @@ impl MysqlDb {
                 collection: bso.collection.clone(),
                 collection_id,
             })?;
-            if usage.total_bytes >= self.quota.size as usize {
+            if usage.total_bytes >= self.quota.size {
                 let mut tags = HashMap::default();
                 tags.insert("collection".to_owned(), bso.collection.clone());
                 self.metrics.incr_with_tags("storage.quota.at_limit", tags);
@@ -489,7 +489,7 @@ impl MysqlDb {
                 bso::expiry,
             ))
             .filter(bso::user_id.eq(user_id))
-            .filter(bso::collection_id.eq(collection_id as i32)) // XXX:
+            .filter(bso::collection_id.eq(collection_id))
             .filter(bso::expiry.gt(now))
             .into_boxed();
 
@@ -572,7 +572,7 @@ impl MysqlDb {
         let mut query = bso::table
             .select(bso::id)
             .filter(bso::user_id.eq(user_id))
-            .filter(bso::collection_id.eq(collection_id as i32)) // XXX:
+            .filter(bso::collection_id.eq(collection_id))
             .filter(bso::expiry.gt(self.timestamp().as_i64()))
             .into_boxed();
 
diff --git a/syncserver/src/db/spanner/models.rs b/syncserver/src/db/spanner/models.rs
index 50eef358..74b111fc 100644
--- a/syncserver/src/db/spanner/models.rs
+++ b/syncserver/src/db/spanner/models.rs
@@ -1662,7 +1662,7 @@ impl SpannerDb {
                 warn!("Quota at limit for user's collection: ({} bytes)", usage.total_bytes; "collection"=>collection);
             }
         }
-        Ok(Some(usage.total_bytes as usize))
+        Ok(Some(usage.total_bytes))
     }
 
     // NOTE: Currently this put_bso_async_test impl. is only used during db tests,
diff --git a/syncserver/src/db/tests/db.rs b/syncserver/src/db/tests/db.rs
index 346501e1..28c8b515 100644
--- a/syncserver/src/db/tests/db.rs
+++ b/syncserver/src/db/tests/db.rs
@@ -625,7 +625,7 @@ async fn get_collection_usage() -> Result<()> {
             db.put_bso(pbso(
                 uid,
                 coll,
-                &format!("b{}", i as i32),
+                &format!("b{}", i),
                 Some(&String::from_utf8_lossy(&payload)),
                 None,
                 None,
diff --git a/syncserver/src/tokenserver/handlers.rs b/syncserver/src/tokenserver/handlers.rs
index 855efa51..2e8c529a 100644
--- a/syncserver/src/tokenserver/handlers.rs
+++ b/syncserver/src/tokenserver/handlers.rs
@@ -83,7 +83,7 @@ fn get_token_plaintext(
                 context: format!("Failed to decode the client state hex: {}", e),
                 ..TokenserverError::internal_error()
             })?;
-        let client_state_b64 = base64::encode_config(&client_state, base64::URL_SAFE_NO_PAD);
+        let client_state_b64 = base64::encode_config(client_state, base64::URL_SAFE_NO_PAD);
 
         format!(
             "{:013}-{:}",
diff --git a/syncserver/src/web/handlers.rs b/syncserver/src/web/handlers.rs
index 762f5bca..df5dbc63 100644
--- a/syncserver/src/web/handlers.rs
+++ b/syncserver/src/web/handlers.rs
@@ -313,7 +313,7 @@ pub async fn post_collection_batch(
             CreateBatch {
                 id: id.clone(),
                 size: if coll.quota_enabled {
-                    Some(usage.total_bytes as usize)
+                    Some(usage.total_bytes)
                 } else {
                     None
                 },