Remove unnecessary usage of HashMap.contains_key

src/stv/meek.rs

@@ -69,14 +69,15 @@ impl<'t, N: Number> BallotTree<'t, N> {
 				
 				let candidate = &candidates[*preference.first().unwrap()];
 				
-				if next_preferences.contains_key(candidate) {
+				match next_preferences.get_mut(candidate) {
-					let np_bt = next_preferences.get_mut(candidate).unwrap();
+					Some(np_bt) => {
 						np_bt.num_ballots += &bit.ballot.orig_value;
 						np_bt.ballots.push(BallotInTree {
 							ballot: bit.ballot,
 							up_to_pref: bit.up_to_pref + 1,
 						});
-				} else {
+					}
+					None => {
 						let mut np_bt = BallotTree::new();
 						np_bt.num_ballots += &bit.ballot.orig_value;
 						np_bt.ballots.push(BallotInTree {
@@ -85,6 +86,7 @@ impl<'t, N: Number> BallotTree<'t, N> {
 						});
 						next_preferences.insert(candidate, np_bt);
 					}
+				}
 			} else {
 				// Exhausted
 				next_exhausted.num_ballots += &bit.ballot.orig_value;

src/stv/mod.rs

@@ -823,17 +823,19 @@ pub fn next_preferences<'a, N: Number>(state: &CountState<'a, N>, votes: Vec<Vot
 		
 		// Have to structure like this to satisfy Rust's borrow checker
 		if let Some(candidate) = next_candidate {
-			if result.candidates.contains_key(candidate) {
+			match result.candidates.get_mut(candidate) {
-				let entry = result.candidates.get_mut(candidate).unwrap();
+				Some(entry) => {
 					entry.num_ballots += &vote.ballot.orig_value;
 					entry.votes.push(vote);
-			} else {
+				}
+				None => {
 					let entry = NextPreferencesEntry {
 						num_ballots: vote.ballot.orig_value.clone(),
 						votes: vec![vote],
 					};
 					result.candidates.insert(candidate, entry);
 				}
+			}
 		} else {
 			result.exhausted.num_ballots += &vote.ballot.orig_value;
 			result.exhausted.votes.push(vote);