type-none-comparison (FURB169)

Derived from the refurb linter.

Fix is always available.

What it does

Checks for uses of type that compare the type of an object to the type of None.

Why is this bad?

There is only ever one instance of None, so it is more efficient and readable to use the is operator to check if an object is None.

Only name expressions (e.g., type(foo) == type(None)) are reported. In preview, the rule will also report other kinds of expressions.

Example

type(obj) is type(None)

Use instead:

obj is None

Fix safety

If the fix might remove comments, it will be marked as unsafe.

References

• Python documentation: isinstance
• Python documentation: None
• Python documentation: type
• Python documentation: Identity comparisons