diff --git a/enumer b/enumer
new file mode 100755
index 0000000..0339fa9
Binary files /dev/null and b/enumer differ
diff --git a/stringer.go b/stringer.go
index 9b142da..38891c4 100644
--- a/stringer.go
+++ b/stringer.go
@@ -67,6 +67,7 @@ import (
 	"go/format"
 	"go/parser"
 	"go/token"
+	"go/types"
 	"io/ioutil"
 	"log"
 	"os"
@@ -74,10 +75,9 @@ import (
 	"sort"
 	"strings"
 
-	"golang.org/x/tools/go/exact"
-	"golang.org/x/tools/go/types"
+	exact "go/constant"
 
-	_ "golang.org/x/tools/go/gcimporter"
+	_ "go/importer"
 )
 
 var (