Add test and fix for copy of anonymous field with unexported fields

copier.go

@@ -372,10 +372,10 @@ func deepFields(reflectType reflect.Type) []reflect.StructField {
 			// field name. It is empty for upper case (exported) field names.
 			// See https://golang.org/ref/spec#Uniqueness_of_identifiers
 			if v.PkgPath == "" {
+				fields = append(fields, v)
 				if v.Anonymous {
+					// also consider fields of anonymous fields as fields of the root
 					fields = append(fields, deepFields(v.Type)...)
-				} else {
-					fields = append(fields, v)
 				}
 			}
 		}

copier_test.go

@@ -1453,3 +1453,20 @@ func TestDeepCopySimpleTime(t *testing.T) {
 		t.Errorf("to (%v) value should equal from (%v) value", to, from)
 	}
 }
+
+type TimeWrapper struct{
+	time.Time
+}
+
+func TestDeepCopyAnonymousFieldTime(t *testing.T) {
+	from := TimeWrapper{time.Now()}
+	to := TimeWrapper{}
+
+	err := copier.CopyWithOption(&to, from, copier.Option{DeepCopy: true})
+	if err != nil {
+		t.Error("should not error")
+	}
+	if !from.Time.Equal(to.Time) {
+		t.Errorf("to (%v) value should equal from (%v) value", to.Time, from.Time)
+	}
+}