diff --git a/gen.go b/gen.go
index bf610900db280b13d3620915d32618f56743725c..e93e00c19fa4a6928ac023772bb1be815ef9030f 100644
--- a/gen.go
+++ b/gen.go
@@ -57,6 +57,7 @@ package {{ .Package }}
 import (
 	"fmt"
 	"io"
+	"math"
 	"sort"
 
 {{ range .Imports }}{{ .Name }} "{{ .PkgPath }}"
@@ -66,6 +67,7 @@ import (
 
 var _ = xerrors.Errorf
 var _ = cid.Undef
+var _ = math.E
 var _ = sort.Sort
 
 `)
diff --git a/testing/cbor_gen.go b/testing/cbor_gen.go
index d80833341220f39d6a2a980a3dd2a8a3f374ab29..f587961e7b61864e610b21bd44b305c93763124e 100644
--- a/testing/cbor_gen.go
+++ b/testing/cbor_gen.go
@@ -5,6 +5,7 @@ package testing
 import (
 	"fmt"
 	"io"
+	"math"
 	"sort"
 
 	cid "github.com/ipfs/go-cid"
@@ -14,6 +15,7 @@ import (
 
 var _ = xerrors.Errorf
 var _ = cid.Undef
+var _ = math.E
 var _ = sort.Sort
 
 var lengthBufSignedArray = []byte{129}
diff --git a/testing/cbor_map_gen.go b/testing/cbor_map_gen.go
index 3abb21e8b3d87f169bcaa5e251c6389c79aaf54a..b7d9000067647a4efaa8c8c87804ea98e718592f 100644
--- a/testing/cbor_map_gen.go
+++ b/testing/cbor_map_gen.go
@@ -5,6 +5,7 @@ package testing
 import (
 	"fmt"
 	"io"
+	"math"
 	"sort"
 
 	cid "github.com/ipfs/go-cid"
@@ -14,6 +15,7 @@ import (
 
 var _ = xerrors.Errorf
 var _ = cid.Undef
+var _ = math.E
 var _ = sort.Sort
 
 func (t *SimpleTypeTree) MarshalCBOR(w io.Writer) error {