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Explain generic Protocol[T1, T2, ...] shorthand in Mypy docs #12047

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Explain generic Protocol[T1, T2, ...] shorthand in Mypy docs #12047

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4 changes: 4 additions & 0 deletions docs/source/generics.rst
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Expand Up @@ -673,6 +673,10 @@ protocols mostly follow the normal rules for generic classes. Example:
y: Box[int] = ...
x = y # Error -- Box is invariant

Per :pep:`PEP 544: Generic protocols <544#generic-protocols>`, ``class
ClassName(Protocol[T])`` is allowed as a shorthand for ``class
ClassName(Protocol, Generic[T])``.

The main difference between generic protocols and ordinary generic
classes is that mypy checks that the declared variances of generic
type variables in a protocol match how they are used in the protocol
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