Categories

This page describes the different categories of type system unsoundness that the checker can detect.

runtime-modification

Runtime code modifications that escape static type checker analysis.

Rules in this category

• invalid-function-defaults - detects invalid mutation of the __defaults__ attribute of a function
• mutating-function-code-attribute - detects mutating the __code__ attribute of a function
• mutating-globals-dict - detects mutations to the globals() dictionary
• mutable-generic-default - detects mutable default arguments in generic functions
• invalid-setattr - detects invalid usage of setattr() built-in function

type-checking-suppression

Mechanisms that suppress or bypass type checker warnings.

Rules in this category

• typing-any-used - detects usage of typing.Any in type annotations
• invalid-overload-implementation - detects invalid overload implementation
• typing-overload-used - detects usage of overloaded functions
• type-checking-directive-used - detects usage of type checking directives in comments
• if-type-checking-used - detects usage of if TYPE_CHECKING: blocks
• typing-cast-used - detects usage of typing.cast() function calls
• typing-type-is-used - detects usage of typing.TypeIs in return type annotations
• callable-ellipsis-used - detects usage of ... in the first argument of Callable type annotations
• mangled-dunder-instance-variable - detects explicit usage of mangled dunder instance variables