Error merging into Optional[List[int]] = None

[omry]

repro:

from dataclasses import dataclass
from typing import Optional, List
from omegaconf import OmegaConf


@dataclass
class Config:
    my_field: Optional[List[int]] = None


OmegaConf.merge(Config, Config)

This is a bug in 2.0 and also in master (and should be fixed in both).

[omry]

Fixed in 19da4a4 for 2.0.
2.0.4 coming.

[omry]

#430 fixes in master.
Released 2.1.0-dev10 with this fix.