diff --git a/nonebot/adapters/__init__.py b/nonebot/adapters/__init__.py
index 5d5872bc..18c2e755 100644
--- a/nonebot/adapters/__init__.py
+++ b/nonebot/adapters/__init__.py
@@ -10,7 +10,7 @@ from copy import copy
 from typing_extensions import Literal
 from functools import reduce, partial
 from dataclasses import dataclass, field
-from typing import Any, Dict, Union, TypeVar, Optional, Callable, Iterable, Awaitable, TYPE_CHECKING
+from typing import Any, Dict, Union, TypeVar, Mapping, Optional, Callable, Iterable, Iterator, Awaitable, TYPE_CHECKING
 
 from pydantic import BaseModel
 
@@ -211,8 +211,8 @@ class Message(list, abc.ABC):
     """消息数组"""
 
     def __init__(self,
-                 message: Union[str, list, dict, T_MessageSegment, T_Message,
-                                Any] = None,
+                 message: Union[str, Mapping, Iterable[Mapping],
+                                T_MessageSegment, T_Message, Any] = None,
                  *args,
                  **kwargs):
         """
@@ -242,7 +242,8 @@ class Message(list, abc.ABC):
     @staticmethod
     @abc.abstractmethod
     def _construct(
-            msg: Union[str, list, dict, Any]) -> Iterable[T_MessageSegment]:
+        msg: Union[str, Mapping, Iterable[Mapping], Any]
+    ) -> Iterable[T_MessageSegment]:
         raise NotImplementedError
 
     def __add__(self: T_Message, other: Union[str, T_MessageSegment,
@@ -257,10 +258,20 @@ class Message(list, abc.ABC):
         return result
 
     def __radd__(self: T_Message, other: Union[str, T_MessageSegment,
-                                               T_Message]):
+                                               T_Message]) -> T_Message:
         result = self.__class__(other)
         return result.__add__(self)
 
+    def __iadd__(self: T_Message, other: Union[str, T_MessageSegment,
+                                               T_Message]) -> T_Message:
+        if isinstance(other, str):
+            self.extend(self._construct(other))
+        elif isinstance(other, MessageSegment):
+            self.append(other)
+        elif isinstance(other, Message):
+            self.extend(other)
+        return self
+
     def append(self: T_Message, obj: Union[str, T_MessageSegment]) -> T_Message:
         """
         :说明:
diff --git a/nonebot/adapters/cqhttp/message.py b/nonebot/adapters/cqhttp/message.py
index 466da970..1a7bd538 100644
--- a/nonebot/adapters/cqhttp/message.py
+++ b/nonebot/adapters/cqhttp/message.py
@@ -1,5 +1,5 @@
 import re
-from typing import Any, Dict, Union, Tuple, Iterable, Optional
+from typing import Any, Dict, Union, Tuple, Mapping, Iterable, Optional
 
 from nonebot.typing import overrides
 from nonebot.adapters import Message as BaseMessage, MessageSegment as BaseMessageSegment
@@ -212,11 +212,13 @@ class Message(BaseMessage):
 
     @staticmethod
     @overrides(BaseMessage)
-    def _construct(msg: Union[str, dict, list]) -> Iterable[MessageSegment]:
-        if isinstance(msg, dict):
+    def _construct(
+        msg: Union[str, Mapping,
+                   Iterable[Mapping]]) -> Iterable[MessageSegment]:
+        if isinstance(msg, Mapping):
             yield MessageSegment(msg["type"], msg.get("data") or {})
             return
-        elif isinstance(msg, list):
+        elif isinstance(msg, Iterable) and not isinstance(msg, str):
             for seg in msg:
                 yield MessageSegment(seg["type"], seg.get("data") or {})
             return
diff --git a/nonebot/adapters/ding/message.py b/nonebot/adapters/ding/message.py
index 2c0fa336..93b0b008 100644
--- a/nonebot/adapters/ding/message.py
+++ b/nonebot/adapters/ding/message.py
@@ -1,5 +1,5 @@
 from copy import copy
-from typing import Any, Dict, Union, Iterable
+from typing import Any, Dict, Union, Mapping, Iterable
 
 from nonebot.typing import overrides
 from nonebot.adapters import Message as BaseMessage, MessageSegment as BaseMessageSegment
@@ -133,17 +133,20 @@ class Message(BaseMessage):
 
     @staticmethod
     @overrides(BaseMessage)
-    def _construct(msg: Union[str, dict, list]) -> Iterable[MessageSegment]:
-        if isinstance(msg, dict):
+    def _construct(
+        msg: Union[str, Mapping,
+                   Iterable[Mapping]]) -> Iterable[MessageSegment]:
+        if isinstance(msg, Mapping):
             yield MessageSegment(msg["type"], msg.get("data") or {})
-        elif isinstance(msg, list):
-            for seg in msg:
-                yield MessageSegment(seg["type"], seg.get("data") or {})
         elif isinstance(msg, str):
             yield MessageSegment.text(msg)
+        elif isinstance(msg, Iterable):
+            for seg in msg:
+                yield MessageSegment(seg["type"], seg.get("data") or {})
 
     def _produce(self) -> dict:
         data = {}
+        segment: MessageSegment
         for segment in self:
             # text 可以和 text 合并
             if segment.type == "text" and data.get("msgtype") == 'text':
diff --git a/nonebot/plugin.py b/nonebot/plugin.py
index 7aa46941..e56cd69f 100644
--- a/nonebot/plugin.py
+++ b/nonebot/plugin.py
@@ -897,7 +897,10 @@ def load_plugins(*plugin_dir: str) -> Set[Plugin]:
             return None
 
         spec = module_info.module_finder.find_spec(name, None)
-        if spec.name in plugins:
+        if not spec:
+            logger.warning(
+                f"Module {name} cannot be loaded! Check module name first.")
+        elif spec.name in plugins:
             return None
         elif spec.name in sys.modules:
             logger.warning(