Fix missing import for external []byte alias

sszgen/generator/unmarshal.go

@@ -39,22 +39,18 @@ func (v *Value) unmarshal(dst string) string {
 			validate = fmt.Sprintf("if len(%s) > %d { return ssz.ErrBytesLength }\n", dst, v.m)
 		}
 
-		refName := ""
-		if v.ref != "" {
-			refName = v.ref + "." + v.obj
-		}
-
 		// both fixed and dynamic are decoded equally
 		tmpl := `{{.validate}}if cap(::.{{.name}}) == 0 {
-			{{if .refName}} ::.{{.name}} = {{ .refName }}(make([]byte, 0, len({{.dst}}))) {{ else }} ::.{{.name}} = make([]byte, 0, len({{.dst}})) {{ end }}
+			{{if .isRef}} ::.{{.name}} = {{ ref .obj }}(make([]byte, 0, len({{.dst}}))) {{ else }} ::.{{.name}} = make([]byte, 0, len({{.dst}})) {{ end }}
 		}
 		::.{{.name}} = append(::.{{.name}}, {{.dst}}...)`
 		return execTmpl(tmpl, map[string]interface{}{
 			"validate": validate,
 			"name":     v.name,
 			"dst":      dst,
 			"size":     v.m,
-			"refName":  refName,
+			"isRef":    v.ref != "",
+			"obj":      v,
 		})
 
 	case TypeUint:

sszgen/testcases/issue_166.go

@@ -0,0 +1,9 @@
+package testcases
+
+//go:generate go run ../main.go --path issue_165.go --include ./other
+
+import "github.com/ferranbt/fastssz/sszgen/testcases/other"
+
+type Issue165 struct {
+	A other.Case4Bytes
+}