unnecessary-type-union (PYI055)

Derived from the flake8-pyi linter.

Fix is sometimes available.

What it does

Checks for the presence of multiple types in a union.

Why is this bad?

type[T | S] has identical semantics to type[T] | type[S] in a type annotation, but is cleaner and more concise.

Example

field: type[int] | type[float] | str

Use instead:

field: type[int | float] | str

Fix safety

This rule's fix is marked as safe in most cases; however, the fix will flatten nested unions type expressions into a single top-level union.

The fix is marked as unsafe when comments are present within the type expression.