Avoid blanket implementing FeeEstimator for Deref<FeeEstimator>

This simplifies things for bindings (and, to some extent,
downstream users) by exploiting the fact that we can always "clone"
a reference to a struct by dereferencing and then creating a new
reference.

Author: TheBlueMatt

fuzz/src/chanmon_consistency.rs

@@ -140,7 +140,7 @@ impl chain::Watch<EnforcingSigner> for TestChainMonitor {
 		};
 		let deserialized_monitor = <(BlockHash, channelmonitor::ChannelMonitor<EnforcingSigner>)>::
 			read(&mut Cursor::new(&map_entry.get().1), &*self.keys).unwrap().1;
-		deserialized_monitor.update_monitor(&update, &&TestBroadcaster{}, &&FuzzEstimator { ret_val: atomic::AtomicU32::new(253) }, &self.logger).unwrap();
+		deserialized_monitor.update_monitor(&update, &&TestBroadcaster{}, &FuzzEstimator { ret_val: atomic::AtomicU32::new(253) }, &self.logger).unwrap();
 		let mut ser = VecWriter(Vec::new());
 		deserialized_monitor.write(&mut ser).unwrap();
 		map_entry.insert((update.update_id, ser.0));

lightning/src/chain/chaininterface.rs

@@ -52,14 +52,6 @@ pub trait FeeEstimator {
 	fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32;
 }
 
-// We need `FeeEstimator` implemented so that in some places where we only have a shared
-// reference to a `Deref` to a `FeeEstimator`, we can still wrap it.
-impl<D: Deref> FeeEstimator for D where D::Target: FeeEstimator {
-	fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32 {
-		(**self).get_est_sat_per_1000_weight(confirmation_target)
-	}
-}
-
 /// Minimum relay fee as required by bitcoin network mempool policy.
 pub const MIN_RELAY_FEE_SAT_PER_1000_WEIGHT: u64 = 4000;
 /// Minimum feerate that takes a sane approach to bitcoind weight-to-vbytes rounding.

lightning/src/chain/chainmonitor.rs

@@ -636,7 +636,7 @@ where C::Target: chain::Filter,
 			Some(monitor_state) => {
 				let monitor = &monitor_state.monitor;
 				log_trace!(self.logger, "Updating ChannelMonitor for channel {}", log_funding_info!(monitor));
-				let update_res = monitor.update_monitor(&update, &self.broadcaster, &self.fee_estimator, &self.logger);
+				let update_res = monitor.update_monitor(&update, &self.broadcaster, &*self.fee_estimator, &self.logger);
 				if update_res.is_err() {
 					log_error!(self.logger, "Failed to update ChannelMonitor for channel {}.", log_funding_info!(monitor));
 				}

lightning/src/chain/channelmonitor.rs

@@ -1134,7 +1134,7 @@ impl<Signer: Sign> ChannelMonitor<Signer> {
 		&self,
 		updates: &ChannelMonitorUpdate,
 		broadcaster: &B,
-		fee_estimator: &F,
+		fee_estimator: F,
 		logger: &L,
 	) -> Result<(), ()>
 	where
@@ -1944,10 +1944,10 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 		self.pending_monitor_events.push(MonitorEvent::CommitmentTxConfirmed(self.funding_info.0));
 	}
 
-	pub fn update_monitor<B: Deref, F: Deref, L: Deref>(&mut self, updates: &ChannelMonitorUpdate, broadcaster: &B, fee_estimator: &F, logger: &L) -> Result<(), ()>
+	pub fn update_monitor<B: Deref, F: Deref, L: Deref>(&mut self, updates: &ChannelMonitorUpdate, broadcaster: &B, fee_estimator: F, logger: &L) -> Result<(), ()>
 	where B::Target: BroadcasterInterface,
-		    F::Target: FeeEstimator,
-		    L::Target: Logger,
+		F::Target: FeeEstimator,
+		L::Target: Logger,
 	{
 		log_info!(logger, "Applying update to monitor {}, bringing update_id from {} to {} with {} changes.",
 			log_funding_info!(self), self.latest_update_id, updates.update_id, updates.updates.len());
@@ -1985,7 +1985,7 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 				},
 				ChannelMonitorUpdateStep::PaymentPreimage { payment_preimage } => {
 					log_trace!(logger, "Updating ChannelMonitor with payment preimage");
-					let bounded_fee_estimator = LowerBoundedFeeEstimator::new(fee_estimator);
+					let bounded_fee_estimator = LowerBoundedFeeEstimator::new(&*fee_estimator);
 					self.provide_payment_preimage(&PaymentHash(Sha256::hash(&payment_preimage.0[..]).into_inner()), &payment_preimage, broadcaster, &bounded_fee_estimator, logger)
 				},
 				ChannelMonitorUpdateStep::CommitmentSecret { idx, secret } => {
@@ -3534,7 +3534,7 @@ mod tests {
 
 		let broadcaster = TestBroadcaster::new(Arc::clone(&nodes[1].blocks));
 		assert!(
-			pre_update_monitor.update_monitor(&replay_update, &&broadcaster, &&chanmon_cfgs[1].fee_estimator, &nodes[1].logger)
+			pre_update_monitor.update_monitor(&replay_update, &&broadcaster, &chanmon_cfgs[1].fee_estimator, &nodes[1].logger)
 			.is_err());
 		// Even though we error'd on the first update, we should still have generated an HTLC claim
 		// transaction