diff --git a/config.nims b/config.nims
index da72649d4..93ecec949 100644
--- a/config.nims
+++ b/config.nims
@@ -5,6 +5,7 @@ if dirExists("nimbledeps/pkgs"):
 switch("warning", "CaseTransition:off")
 switch("warning", "ObservableStores:off")
 switch("warning", "LockLevel:off")
+switch("warningAsError", "UseBase:on")
 --define:chronosStrictException
 --styleCheck:usages
 if (NimMajor, NimMinor) < (1, 6):
diff --git a/libp2p/muxers/mplex/coder.nim b/libp2p/muxers/mplex/coder.nim
index f2cce3fce..619e7f400 100644
--- a/libp2p/muxers/mplex/coder.nim
+++ b/libp2p/muxers/mplex/coder.nim
@@ -61,7 +61,7 @@ proc readMsg*(conn: Connection): Future[Msg] {.async, gcsafe.} =
 proc writeMsg*(conn: Connection,
                id: uint64,
                msgType: MessageType,
-               data: seq[byte] = @[]): Future[void] =
+               data: sink seq[byte] = @[]): Future[void] =
   var
     left = data.len
     offset = 0
diff --git a/libp2p/muxers/mplex/lpchannel.nim b/libp2p/muxers/mplex/lpchannel.nim
index 5f6faa809..c701c2158 100644
--- a/libp2p/muxers/mplex/lpchannel.nim
+++ b/libp2p/muxers/mplex/lpchannel.nim
@@ -197,7 +197,7 @@ method readOnce*(s: LPChannel,
     await s.reset()
     raise newLPStreamConnDownError(exc)
 
-proc prepareWrite(s: LPChannel, msg: seq[byte]): Future[void] {.async.} =
+proc prepareWrite(s: LPChannel, msg: sink seq[byte]): Future[void] {.async.} =
   # prepareWrite is the slow path of writing a message - see conditions in
   # write
   if s.remoteReset:
@@ -254,7 +254,7 @@ proc completeWrite(
   finally:
     s.writes -= 1
 
-method write*(s: LPChannel, msg: seq[byte]): Future[void] =
+method write*(s: LPChannel, msg: sink seq[byte]): Future[void] =
   ## Write to mplex channel - there may be up to MaxWrite concurrent writes
   ## pending after which the peer is disconnected
 
diff --git a/libp2p/muxers/yamux/yamux.nim b/libp2p/muxers/yamux/yamux.nim
index a5273794d..ca1587cfc 100644
--- a/libp2p/muxers/yamux/yamux.nim
+++ b/libp2p/muxers/yamux/yamux.nim
@@ -265,7 +265,7 @@ method readOnce*(
   channel.activity = true
   return toRead
 
-proc gotDataFromRemote(channel: YamuxChannel, b: seq[byte]) {.async.} =
+proc gotDataFromRemote(channel: YamuxChannel, b: sink seq[byte]) {.async.} =
   channel.recvWindow -= b.len
   channel.recvQueue = channel.recvQueue.concat(b)
   channel.receivedData.fire()
@@ -333,7 +333,7 @@ proc trySend(channel: YamuxChannel) {.async.} =
       fut.complete()
     channel.activity = true
 
-method write*(channel: YamuxChannel, msg: seq[byte]): Future[void] =
+method write*(channel: YamuxChannel, msg: sink seq[byte]): Future[void] =
   result = newFuture[void]("Yamux Send")
   if channel.remoteReset:
     result.fail(newLPStreamResetError())
diff --git a/libp2p/protocols/connectivity/relay/rconn.nim b/libp2p/protocols/connectivity/relay/rconn.nim
index f355fd8a9..1006edfd6 100644
--- a/libp2p/protocols/connectivity/relay/rconn.nim
+++ b/libp2p/protocols/connectivity/relay/rconn.nim
@@ -30,7 +30,7 @@ method readOnce*(
   self.activity = true
   return await self.conn.readOnce(pbytes, nbytes)
 
-method write*(self: RelayConnection, msg: seq[byte]): Future[void] {.async.} =
+method write*(self: RelayConnection, msg: sink seq[byte]): Future[void] {.async.} =
   self.dataSent.inc(msg.len)
   if self.limitData != 0 and self.dataSent > self.limitData:
     await self.close()
diff --git a/libp2p/protocols/identify.nim b/libp2p/protocols/identify.nim
index ae7d26c48..bf8d60c6b 100644
--- a/libp2p/protocols/identify.nim
+++ b/libp2p/protocols/identify.nim
@@ -111,7 +111,7 @@ proc encodeMsg(peerInfo: PeerInfo, observedAddr: Opt[MultiAddress], sendSpr: boo
 
   result.finish()
 
-proc decodeMsg*(buf: seq[byte]): Option[IdentifyInfo] =
+proc decodeMsg*(buf: sink seq[byte]): Option[IdentifyInfo] =
   var
     iinfo: IdentifyInfo
     pubkey: PublicKey
diff --git a/libp2p/protocols/pubsub/floodsub.nim b/libp2p/protocols/pubsub/floodsub.nim
index 0bbf09399..1049773fb 100644
--- a/libp2p/protocols/pubsub/floodsub.nim
+++ b/libp2p/protocols/pubsub/floodsub.nim
@@ -176,7 +176,7 @@ method init*(f: FloodSub) =
 
 method publish*(f: FloodSub,
                 topic: string,
-                data: seq[byte]): Future[int] {.async.} =
+                data: sink seq[byte]): Future[int] {.async.} =
   # base returns always 0
   discard await procCall PubSub(f).publish(topic, data)
 
diff --git a/libp2p/protocols/pubsub/gossipsub.nim b/libp2p/protocols/pubsub/gossipsub.nim
index 92d352655..dccc9aa8c 100644
--- a/libp2p/protocols/pubsub/gossipsub.nim
+++ b/libp2p/protocols/pubsub/gossipsub.nim
@@ -477,7 +477,7 @@ method onTopicSubscription*(g: GossipSub, topic: string, subscribed: bool) =
 
 method publish*(g: GossipSub,
                 topic: string,
-                data: seq[byte]): Future[int] {.async.} =
+                data: sink seq[byte]): Future[int] {.async.} =
   # base returns always 0
   discard await procCall PubSub(g).publish(topic, data)
 
diff --git a/libp2p/protocols/pubsub/pubsub.nim b/libp2p/protocols/pubsub/pubsub.nim
index a7d7fc210..f96832226 100644
--- a/libp2p/protocols/pubsub/pubsub.nim
+++ b/libp2p/protocols/pubsub/pubsub.nim
@@ -84,6 +84,7 @@ declarePublicCounter(libp2p_pubsub_received_prune, "pubsub broadcast prune", lab
 type
   InitializationError* = object of LPError
 
+  #TODO sink?
   TopicHandler* {.public.} = proc(topic: string,
                        data: seq[byte]): Future[void] {.gcsafe, raises: [Defect].}
 
@@ -311,7 +312,7 @@ proc getOrCreatePeer*(
 
   return pubSubPeer
 
-proc handleData*(p: PubSub, topic: string, data: seq[byte]): Future[void] =
+proc handleData*(p: PubSub, topic: string, data: sink seq[byte]): Future[void] =
   # Start work on all data handlers without copying data into closure like
   # happens on {.async.} transformation
   p.topics.withValue(topic, handlers) do:
@@ -474,7 +475,7 @@ proc subscribe*(p: PubSub,
 
 method publish*(p: PubSub,
                 topic: string,
-                data: seq[byte]): Future[int] {.base, async, public.} =
+                data: sink seq[byte]): Future[int] {.base, async, public.} =
   ## publish to a ``topic``
   ##
   ## The return value is the number of neighbours that we attempted to send the
diff --git a/libp2p/protocols/pubsub/pubsubpeer.nim b/libp2p/protocols/pubsub/pubsubpeer.nim
index 5a1afedbd..fe85e2477 100644
--- a/libp2p/protocols/pubsub/pubsubpeer.nim
+++ b/libp2p/protocols/pubsub/pubsubpeer.nim
@@ -210,7 +210,7 @@ proc connectImpl(p: PubSubPeer) {.async.} =
 proc connect*(p: PubSubPeer) =
   asyncSpawn connectImpl(p)
 
-proc sendImpl(conn: Connection, encoded: seq[byte]): Future[void] {.raises: [Defect].} =
+proc sendImpl(conn: Connection, encoded: sink seq[byte]): Future[void] {.raises: [Defect].} =
   trace "sending encoded msgs to peer", conn, encoded = shortLog(encoded)
 
   let fut = conn.writeLp(encoded) # Avoid copying `encoded` into future
@@ -237,7 +237,7 @@ template sendMetrics(msg: RPCMsg): untyped =
         # metrics
         libp2p_pubsub_sent_messages.inc(labelValues = [$p.peerId, t])
 
-proc sendEncoded*(p: PubSubPeer, msg: seq[byte]) {.raises: [Defect].} =
+proc sendEncoded*(p: PubSubPeer, msg: sink seq[byte]) {.raises: [Defect].} =
   doAssert(not isNil(p), "pubsubpeer nil!")
 
   if msg.len <= 0:
diff --git a/libp2p/protocols/pubsub/rpc/protobuf.nim b/libp2p/protocols/pubsub/rpc/protobuf.nim
index 1b4cd2268..48ffbc6d9 100644
--- a/libp2p/protocols/pubsub/rpc/protobuf.nim
+++ b/libp2p/protocols/pubsub/rpc/protobuf.nim
@@ -322,7 +322,7 @@ proc encodeRpcMsg*(msg: RPCMsg, anonymize: bool): seq[byte] =
     pb.finish()
   pb.buffer
 
-proc decodeRpcMsg*(msg: seq[byte]): ProtoResult[RPCMsg] {.inline.} =
+proc decodeRpcMsg*(msg: sink seq[byte]): ProtoResult[RPCMsg] {.inline.} =
   trace "decodeRpcMsg: decoding message", msg = msg.shortLog()
   var pb = initProtoBuffer(msg)
   var rpcMsg = ok(RPCMsg())
diff --git a/libp2p/protocols/secure/noise.nim b/libp2p/protocols/secure/noise.nim
index 66a8dcd22..5a119cff7 100644
--- a/libp2p/protocols/secure/noise.nim
+++ b/libp2p/protocols/secure/noise.nim
@@ -333,7 +333,7 @@ proc sendHSMessage(sconn: Connection, buf: openArray[byte]): Future[void] =
 
 proc handshakeXXOutbound(
     p: Noise, conn: Connection,
-    p2pSecret: seq[byte]): Future[HandshakeResult] {.async.} =
+    p2pSecret: sink seq[byte]): Future[HandshakeResult] {.async.} =
   const initiator = true
   var
     hs = HandshakeState.init()
@@ -381,7 +381,7 @@ proc handshakeXXOutbound(
 
 proc handshakeXXInbound(
     p: Noise, conn: Connection,
-    p2pSecret: seq[byte]): Future[HandshakeResult] {.async.} =
+    p2pSecret: sink seq[byte]): Future[HandshakeResult] {.async.} =
   const initiator = false
 
   var
@@ -461,7 +461,7 @@ proc encryptFrame(
 
   cipherFrame[2 + src.len()..<cipherFrame.len] = tag
 
-method write*(sconn: NoiseConnection, message: seq[byte]): Future[void] =
+method write*(sconn: NoiseConnection, message: sink seq[byte]): Future[void] =
   # Fast path: `{.async.}` would introduce a copy of `message`
   const FramingSize = 2 + sizeof(ChaChaPolyTag)
 
diff --git a/libp2p/protocols/secure/secio.nim b/libp2p/protocols/secure/secio.nim
index 1ebea90b2..350231fb0 100644
--- a/libp2p/protocols/secure/secio.nim
+++ b/libp2p/protocols/secure/secio.nim
@@ -226,7 +226,7 @@ method readMessage*(sconn: SecioConn): Future[seq[byte]] {.async.} =
     trace "Message MAC verification failed", buf = buf.shortLog
     raise (ref SecioError)(msg: "message failed MAC verification")
 
-method write*(sconn: SecioConn, message: seq[byte]) {.async.} =
+method write*(sconn: SecioConn, message: sink seq[byte]) {.async.} =
   ## Write message ``message`` to secure connection ``sconn``.
   if message.len == 0:
     return
diff --git a/libp2p/stream/bufferstream.nim b/libp2p/stream/bufferstream.nim
index 68cf862c7..57ce82c1e 100644
--- a/libp2p/stream/bufferstream.nim
+++ b/libp2p/stream/bufferstream.nim
@@ -68,7 +68,7 @@ proc new*(
   bufferStream.initStream()
   bufferStream
 
-method pushData*(s: BufferStream, data: seq[byte]) {.base, async.} =
+method pushData*(s: BufferStream, data: sink seq[byte]) {.base, async.} =
   ## Write bytes to internal read buffer, use this to fill up the
   ## buffer with data.
   ##
diff --git a/libp2p/stream/chronosstream.nim b/libp2p/stream/chronosstream.nim
index 7f26a44ee..f37c4af32 100644
--- a/libp2p/stream/chronosstream.nim
+++ b/libp2p/stream/chronosstream.nim
@@ -127,7 +127,7 @@ proc completeWrite(
       if s.tracked:
         libp2p_peers_traffic_write.inc(msgLen.int64, labelValues = [s.shortAgent])
 
-method write*(s: ChronosStream, msg: seq[byte]): Future[void] =
+method write*(s: ChronosStream, msg: sink seq[byte]): Future[void] =
   # Avoid a copy of msg being kept in the closure created by `{.async.}` as this
   # drives up memory usage
   if msg.len == 0:
diff --git a/libp2p/stream/lpstream.nim b/libp2p/stream/lpstream.nim
index e2b73278b..11abbbae2 100644
--- a/libp2p/stream/lpstream.nim
+++ b/libp2p/stream/lpstream.nim
@@ -283,7 +283,7 @@ proc readLp*(s: LPStream, maxSize: int): Future[seq[byte]] {.async, gcsafe, publ
   await s.readExactly(addr res[0], res.len)
   return res
 
-method write*(s: LPStream, msg: seq[byte]): Future[void] {.base, public.} =
+method write*(s: LPStream, msg: sink seq[byte]): Future[void] {.base, public.} =
   # Write `msg` to stream, waiting for the write to be finished
   doAssert(false, "not implemented!")
 
diff --git a/libp2p/transports/wstransport.nim b/libp2p/transports/wstransport.nim
index 9ded1c1e7..d954eef06 100644
--- a/libp2p/transports/wstransport.nim
+++ b/libp2p/transports/wstransport.nim
@@ -83,7 +83,7 @@ method readOnce*(
 
 method write*(
   s: WsStream,
-  msg: seq[byte]): Future[void] {.async.} =
+  msg: sink seq[byte]): Future[void] {.async.} =
   mapExceptions(await s.session.send(msg, Opcode.Binary))
   s.activity = true # reset activity flag
 
diff --git a/tests/helpers.nim b/tests/helpers.nim
index d79ca72f9..17da86479 100644
--- a/tests/helpers.nim
+++ b/tests/helpers.nim
@@ -81,7 +81,7 @@ type
   TestBufferStream* = ref object of BufferStream
     writeHandler*: WriteHandler
 
-method write*(s: TestBufferStream, msg: seq[byte]): Future[void] =
+method write*(s: TestBufferStream, msg: sink seq[byte]): Future[void] =
   s.writeHandler(msg)
 
 proc new*(T: typedesc[TestBufferStream], writeHandler: WriteHandler): T =
diff --git a/tests/testmultistream.nim b/tests/testmultistream.nim
index 6bdf1aa40..4e7989a45 100644
--- a/tests/testmultistream.nim
+++ b/tests/testmultistream.nim
@@ -57,7 +57,7 @@ method readOnce*(s: TestSelectStream,
 
       return "\0x3na\n".len()
 
-method write*(s: TestSelectStream, msg: seq[byte]) {.async, gcsafe.} = discard
+method write*(s: TestSelectStream, msg: sink seq[byte]) {.async, gcsafe.} = discard
 
 method close(s: TestSelectStream) {.async, gcsafe.} =
   s.isClosed = true
@@ -106,7 +106,7 @@ method readOnce*(s: TestLsStream,
       copyMem(pbytes, addr buf[0], buf.len())
       return buf.len()
 
-method write*(s: TestLsStream, msg: seq[byte]) {.async, gcsafe.} =
+method write*(s: TestLsStream, msg: sink seq[byte]) {.async, gcsafe.} =
   if s.step == 4:
     await s.ls(msg)
 
@@ -160,7 +160,7 @@ method readOnce*(s: TestNaStream,
 
       return "\0x3na\n".len()
 
-method write*(s: TestNaStream, msg: seq[byte]) {.async, gcsafe.} =
+method write*(s: TestNaStream, msg: sink seq[byte]) {.async, gcsafe.} =
   if s.step == 4:
     await s.na(string.fromBytes(msg))