dict_key_hashable error

Unhashable type used as a dict key

Lists, sets, and plain dicts are not hashable and cannot be used as dictionary keys at runtime. Basilisk detects these statically.

def bad_key() -> None:
    mapping = {[1, 2]: "value"}   # list as key → E0022

How to handle it

Every rule is on by default — strict is the default, not a cage. You can dial dict_key_hashable down per-file or per-path from your editor or pyproject.toml, or fix the code so it type-checks. See the Type System rules and the complete diagnostic reference.

Canonical URL: https://www.basilisk-python.dev/errors/dict_key_hashable