unhashable-member / E1143

Message emitted:

'%s' is unhashable and can't be used as a %s in a %s

Description:

Emitted when a dict key or set member is not hashable (i.e. doesn't define __hash__ method).

Problematic code:

# Print the number of apples:
print({"apple": 42}[["apple"]])  # [unhashable-member]

Correct code:

# Print the number of apples:
print({"apple": 42}["apple"])

Created by the typecheck checker.