diff --git a/.travis.yml b/.travis.yml
index 6ce5865..8f187a8 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,7 +5,7 @@ os:
 language: go
 
 go:
-    - 1.8
+    - 1.10.x
 
 install: true
 
diff --git a/protocols.go b/protocols.go
index 9f78f98..12cfb53 100644
--- a/protocols.go
+++ b/protocols.go
@@ -4,6 +4,7 @@ import (
 	"encoding/binary"
 	"fmt"
 	"strings"
+	"math/bits"
 )
 
 // Protocol is a Multiaddr protocol description structure.
@@ -117,7 +118,7 @@ func ProtocolsWithString(s string) ([]Protocol, error) {
 
 // CodeToVarint converts an integer to a varint-encoded []byte
 func CodeToVarint(num int) []byte {
-	buf := make([]byte, (num/7)+1) // varint package is uint64
+	buf := make([]byte, bits.Len(uint(num))/7 + 1)
 	n := binary.PutUvarint(buf, uint64(num))
 	return buf[:n]
 }
diff --git a/transcoders.go b/transcoders.go
index f6739ed..7f7f645 100644
--- a/transcoders.go
+++ b/transcoders.go
@@ -49,7 +49,7 @@ func ip4StB(s string) ([]byte, error) {
 func ip6StB(s string) ([]byte, error) {
 	i := net.ParseIP(s).To16()
 	if i == nil {
-		return nil, fmt.Errorf("failed to parse ip4 addr: %s", s)
+		return nil, fmt.Errorf("failed to parse ip6 addr: %s", s)
 	}
 	return i, nil
 }