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## Summary Resolves #15695, rework of #15704. This change modifies the Mdtests framework so that: * Paths must now be specified in a separate preceding line: `````markdown `a.py`: ```py x = 1 ``` ````` If the path of a file conflicts with its `lang`, an error will be thrown. * Configs are no longer accepted. The pattern still take them into account, however, to avoid "Unterminated code block" errors. * Unnamed files are now assigned unique, `lang`-respecting paths automatically. Additionally, all legacy usages have been updated. ## Test Plan Unit tests and Markdown tests. --------- Co-authored-by: Carl Meyer <carl@astral.sh>
1.9 KiB
1.9 KiB
PEP 695 Generics
Class Declarations
Basic PEP 695 generics
class MyBox[T]:
data: T
box_model_number = 695
def __init__(self, data: T):
self.data = data
box: MyBox[int] = MyBox(5)
# TODO should emit a diagnostic here (str is not assignable to int)
wrong_innards: MyBox[int] = MyBox("five")
# TODO reveal int, do not leak the typevar
reveal_type(box.data) # revealed: T
reveal_type(MyBox.box_model_number) # revealed: Unknown | Literal[695]
Subclassing
class MyBox[T]:
data: T
def __init__(self, data: T):
self.data = data
# TODO not error on the subscripting
# error: [non-subscriptable]
class MySecureBox[T](MyBox[T]): ...
secure_box: MySecureBox[int] = MySecureBox(5)
reveal_type(secure_box) # revealed: MySecureBox
# TODO reveal int
# The @Todo(…) is misleading here. We currently treat `MyBox[T]` as a dynamic base class because we
# don't understand generics and therefore infer `Unknown` for the `MyBox[T]` base of `MySecureBox[T]`.
reveal_type(secure_box.data) # revealed: @Todo(instance attribute on class with dynamic base)
Cyclical class definition
In type stubs, classes can reference themselves in their base class definitions. For example, in
typeshed
, we have class str(Sequence[str]): ...
.
This should hold true even with generics at play.
class Seq[T]: ...
# TODO not error on the subscripting
class S[T](Seq[S]): ... # error: [non-subscriptable]
reveal_type(S) # revealed: Literal[S]
Type params
A PEP695 type variable defines a value of type typing.TypeVar
.
def f[T]():
reveal_type(T) # revealed: T
reveal_type(T.__name__) # revealed: Literal["T"]
Minimum two constraints
A typevar with less than two constraints emits a diagnostic:
# error: [invalid-type-variable-constraints] "TypeVar must have at least two constrained types"
def f[T: (int,)]():
pass