Enable strict_bytes by default

Author: hauntsaninja

mypy/main.py

@@ -870,9 +870,9 @@ def add_invertible_flag(
     )
 
     add_invertible_flag(
-        "--strict-bytes",
-        default=False,
-        strict_flag=False,
+        "--no-strict-bytes",
+        default=True,
+        dest="strict_bytes",
         help="Disable treating bytearray and memoryview as subtypes of bytes",
         group=strictness_group,
     )

mypy/options.py

@@ -217,7 +217,7 @@ def __init__(self) -> None:
         self.strict_equality = False
 
         # Disable treating bytearray and memoryview as subtypes of bytes
-        self.strict_bytes = False
+        self.strict_bytes = True
 
         # Deprecated, use extra_checks instead.
         self.strict_concatenate = False