Drop InMemorySigner Writeable impl

... which we haven't been using since 0.0.119 / commit
7a951b1.

Author: tnull

lightning/src/sign/mod.rs

@@ -58,11 +58,11 @@ use crate::ln::script::ShutdownScript;
 use crate::offers::invoice::UnsignedBolt12Invoice;
 use crate::offers::invoice_request::UnsignedInvoiceRequest;
 use crate::types::payment::PaymentPreimage;
-use crate::util::ser::{Readable, ReadableArgs, Writeable, Writer};
+use crate::util::ser::{Readable, ReadableArgs, Writeable};
 use crate::util::transaction_utils;
 
 use crate::crypto::chacha20::ChaCha20;
-use crate::io::{self, Error};
+use crate::io;
 use crate::ln::msgs::DecodeError;
 use crate::prelude::*;
 use crate::sign::ecdsa::EcdsaChannelSigner;
@@ -1785,28 +1785,6 @@ impl TaprootChannelSigner for InMemorySigner {
 
 const SERIALIZATION_VERSION: u8 = 1;
 
-const MIN_SERIALIZATION_VERSION: u8 = 1;
-
-impl Writeable for InMemorySigner {
-	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
-		write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
-
-		self.funding_key.write(writer)?;
-		self.revocation_base_key.write(writer)?;
-		self.payment_key.write(writer)?;
-		self.delayed_payment_base_key.write(writer)?;
-		self.htlc_base_key.write(writer)?;
-		self.commitment_seed.write(writer)?;
-		self.channel_parameters.write(writer)?;
-		self.channel_value_satoshis.write(writer)?;
-		self.channel_keys_id.write(writer)?;
-
-		write_tlv_fields!(writer, {});
-
-		Ok(())
-	}
-}
-
 impl<ES: Deref> ReadableArgs<ES> for InMemorySigner
 where
 	ES::Target: EntropySource,

lightning/src/util/test_channel_signer.rs

@@ -9,7 +9,7 @@
 
 use crate::ln::channel::{ANCHOR_OUTPUT_VALUE_SATOSHI, MIN_CHAN_DUST_LIMIT_SATOSHIS};
 use crate::ln::chan_utils::{HTLCOutputInCommitment, ChannelPublicKeys, HolderCommitmentTransaction, CommitmentTransaction, ChannelTransactionParameters, TrustedCommitmentTransaction, ClosingTransaction};
-use crate::ln::channel_keys::{HtlcKey};
+use crate::ln::channel_keys::HtlcKey;
 use crate::ln::msgs;
 use crate::types::payment::PaymentPreimage;
 use crate::sign::{InMemorySigner, ChannelSigner};
@@ -35,8 +35,6 @@ use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature};
 #[cfg(taproot)]
 use musig2::types::{PartialSignature, PublicNonce};
 use crate::sign::HTLCDescriptor;
-use crate::util::ser::{Writeable, Writer};
-use crate::io::Error;
 use crate::types::features::ChannelTypeFeatures;
 #[cfg(taproot)]
 use crate::ln::msgs::PartialSignatureWithNonce;
@@ -402,17 +400,6 @@ impl TaprootChannelSigner for TestChannelSigner {
 	}
 }
 
-impl Writeable for TestChannelSigner {
-	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
-		// TestChannelSigner has two fields - `inner` ([`InMemorySigner`]) and `state`
-		// ([`EnforcementState`]). `inner` is serialized here and deserialized by
-		// [`SignerProvider::read_chan_signer`]. `state` is managed by [`SignerProvider`]
-		// and will be serialized as needed by the implementation of that trait.
-		self.inner.write(writer)?;
-		Ok(())
-	}
-}
-
 impl TestChannelSigner {
 	fn verify_counterparty_commitment_tx<'a, T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &'a CommitmentTransaction, secp_ctx: &Secp256k1<T>) -> TrustedCommitmentTransaction<'a> {
 		commitment_tx.verify(