Store an owned Score in ScorerAccountingForInFlightHtlcs

`ScorerAccountingForInFlightHtlcs` generally stores a `Score`
reference generated by calling `LockableScore::lock`, which
actually returns an arbitrary `Score`. Given `Score` is implemented
directly on lock types, it makes sense to simply hold a fully owned
`Score` in `ScorerAccountingForInFlightHtlcs` rather than a mutable
reference to one.

Author: TheBlueMatt

lightning-invoice/src/payment.rs

@@ -1674,8 +1674,8 @@ mod tests {
 		) -> Result<Route, LightningError> {
 			// Simulate calling the Scorer just as you would in find_route
 			let route = Self::route_for_value(route_params.final_value_msat);
-			let mut locked_scorer = self.scorer.lock();
-			let scorer = ScorerAccountingForInFlightHtlcs::new(locked_scorer.deref_mut(), inflight_htlcs);
+			let locked_scorer = self.scorer.lock();
+			let scorer = ScorerAccountingForInFlightHtlcs::new(locked_scorer, inflight_htlcs);
 			for path in route.paths {
 				let mut aggregate_msat = 0u64;
 				for (idx, hop) in path.iter().rev().enumerate() {

lightning/src/routing/router.rs

@@ -71,7 +71,7 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref, S: Deref> Router for DefaultR
 
 		find_route(
 			payer, params, &self.network_graph, first_hops, &*self.logger,
-			&ScorerAccountingForInFlightHtlcs::new(&mut self.scorer.lock(), inflight_htlcs),
+			&ScorerAccountingForInFlightHtlcs::new(self.scorer.lock(), inflight_htlcs),
 			&random_seed_bytes
 		)
 	}
@@ -125,15 +125,15 @@ pub trait Router {
 /// [`find_route`].
 ///
 /// [`Score`]: crate::routing::scoring::Score
-pub struct ScorerAccountingForInFlightHtlcs<'a, S: Score> {
-	scorer: &'a mut S,
+pub struct ScorerAccountingForInFlightHtlcs<S: Score> {
+	scorer: S,
 	// Maps a channel's short channel id and its direction to the liquidity used up.
 	inflight_htlcs: InFlightHtlcs,
 }
 
-impl<'a, S: Score> ScorerAccountingForInFlightHtlcs<'a, S> {
+impl<S: Score> ScorerAccountingForInFlightHtlcs<S> {
 	/// Initialize a new `ScorerAccountingForInFlightHtlcs`.
-	pub fn new(scorer: &'a mut S, inflight_htlcs: InFlightHtlcs) -> Self {
+	pub fn new(scorer: S, inflight_htlcs: InFlightHtlcs) -> Self {
 		ScorerAccountingForInFlightHtlcs {
 			scorer,
 			inflight_htlcs
@@ -142,11 +142,11 @@ impl<'a, S: Score> ScorerAccountingForInFlightHtlcs<'a, S> {
 }
 
 #[cfg(c_bindings)]
-impl<'a, S:Score> Writeable for ScorerAccountingForInFlightHtlcs<'a, S> {
+impl<S: Score> Writeable for ScorerAccountingForInFlightHtlcs<S> {
 	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> { self.scorer.write(writer) }
 }
 
-impl<'a, S: Score> Score for ScorerAccountingForInFlightHtlcs<'a, S> {
+impl<S: Score> Score for ScorerAccountingForInFlightHtlcs<S> {
 	fn channel_penalty_msat(&self, short_channel_id: u64, source: &NodeId, target: &NodeId, usage: ChannelUsage) -> u64 {
 		if let Some(used_liquidity) = self.inflight_htlcs.used_liquidity_msat(
 			source, target, short_channel_id