Some simple Option / Result / iterator pattern simplifications (#3205)

store/src/leaf_set.rs

@@ -96,8 +96,7 @@ impl LeafSet {
 	/// Only applicable for the output MMR.
 	fn unpruned_pre_cutoff(&self, cutoff_pos: u64, prune_list: &PruneList) -> Bitmap {
 		(1..=cutoff_pos)
-			.filter(|&x| pmmr::is_leaf(x))
-			.filter(|&x| !prune_list.is_pruned(x))
+			.filter(|&x| pmmr::is_leaf(x) && !prune_list.is_pruned(x))
 			.map(|x| x as u32)
 			.collect()
 	}

store/src/types.rs

@@ -107,10 +107,7 @@ where
 	/// Elements can be of variable size (handled internally in the append-only file impl).
 	///
 	pub fn read(&self, position: u64) -> Option<T> {
-		match self.file.read_as_elmt(position - 1) {
-			Ok(x) => Some(x),
-			Err(_) => None,
-		}
+		self.file.read_as_elmt(position - 1).ok()
 	}
 
 	/// Rewind the backend file to the specified position.