experiment enabling by default

Author: michaelm-openai

mypy/main.py

@@ -939,7 +939,7 @@ def add_invertible_flag(
 
     add_invertible_flag(
         "--disallow-str-iteration",
-        default=False,
+        default=True,
         strict_flag=False,
         help="Disallow iterating over str instances",
         group=strictness_group,

mypy/options.py

@@ -240,7 +240,7 @@ def __init__(self) -> None:
         self.strict_bytes = False
 
         # Disallow iterating over str instances or using them as Sequence[T]
-        self.disallow_str_iteration = False
+        self.disallow_str_iteration = True
 
         # Deprecated, use extra_checks instead.
         self.strict_concatenate = False