## Summary
Use `Type::Divergent` to avoid "too many iterations" panic on an
infinitely-nested tuple in an implicit instance attribute.
The regression here is from checking all tuple elements to see if they
contain a Divergent type. It's 5% on one project, 1% on another, and
zero on the rest. I spent some time looking into eliminating this
regression by tracking a flag on inference results to note if they could
possibly contain any Divergent type, but this doesn't really work --
there are too many different ways a type containing a Divergent type
could enter an inference result. Still thinking about whether there are
other ways to reduce this. One option is if we see certain kinds of
non-atomic types that are commonly expensive to check for Divergent, we
could make `has_divergent_type` a Salsa query on those types.
## Test Plan
Added mdtest.
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
`CallableTypeOf[bound_method]` would previously bind `self` to the
bound method type itself, instead of binding it to the instance type
stored inside the bound method type.
## Test Plan
Added regression test
This PR adds a new `ty_extensions.ConstraintSet` class, which is used to
expose constraint sets to our mdtest framework. This lets us write a
large collection of unit tests that exercise the invariants and rewrite
rules of our constraint set implementation.
As part of this, `is_assignable_to` and friends are updated to return a
`ConstraintSet` instead of a `bool`, and we implement
`ConstraintSet.__bool__` to return when a constraint set is always
satisfied. That lets us still use
`static_assert(is_assignable_to(...))`, since the assertion will coerce
the constraint set to a bool, and also lets us
`reveal_type(is_assignable_to(...))` to see more detail about
whether/when the two types are assignable. That lets us get rid of
`reveal_when_assignable_to` and friends, since they are now redundant
with the expanded capabilities of `is_assignable_to`.
## Summary
When adding an enum literal `E = Literal[Color.RED]` to a union which
already contained a subtype of that enum literal(!), we were previously
not simplifying the union correctly. My assumption is that our property
tests didn't catch that earlier, because the only possible non-trivial
subytpe of an enum literal that I can think of is `Any & E`. And in
order for that to be detected by the property tests, it would have to
randomly generate `Any & E | E` and then also compare that with `E` on
the other side (in an equivalence test, or the subtyping-antisymmetry
test).
closes https://github.com/astral-sh/ty/issues/1155
## Test Plan
* Added a regression test.
* I also ran the property tests for a while, but probably not for two
months worth of daily CI runs.
## Summary
This is a follow-up to https://github.com/astral-sh/ruff/pull/19321.
Now lazy snapshots are updated to take into account new bindings on
every symbol reassignment.
```python
def outer(x: A | None):
if x is None:
x = A()
reveal_type(x) # revealed: A
def inner() -> None:
# lazy snapshot: {x: A}
reveal_type(x) # revealed: A
inner()
def outer() -> None:
x = None
x = 1
def inner() -> None:
# lazy snapshot: {x: Literal[1]} -> {x: Literal[1, 2]}
reveal_type(x) # revealed: Literal[1, 2]
inner()
x = 2
```
Closesastral-sh/ty#559.
## Test Plan
Some TODOs in `public_types.md` now work properly.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Adds support for generic PEP695 type aliases, e.g.,
```python
type A[T] = T
reveal_type(A[int]) # A[int]
```
Resolves https://github.com/astral-sh/ty/issues/677.
## Summary
Support cases like the following, where we need the generic context to
include both `Self` and `T` (not just `T`):
```py
from typing import Self
class C:
def method[T](self: Self, arg: T): ...
C().method(1)
```
closes https://github.com/astral-sh/ty/issues/1131
## Test Plan
Added regression test
## Summary
The sub-checks for assignability and subtyping of materializations
performed in `has_relation_in_invariant_position` and
`is_subtype_in_invariant_position` need to propagate the
`HasRelationToVisitor`, or we can stack overflow.
A side effect of this change is that we also propagate the
`ConstraintSet` through, rather than using `C::from_bool`, which I think
may also become important for correctness in cases involving type
variables (though it isn't testable yet, since we aren't yet actually
creating constraints other than always-true and always-false.)
## Test Plan
Added mdtest (derived from code found in pydantic) which
stack-overflowed before this PR.
With this change incorporated, pydantic now checks successfully on my
draft PR for PEP 613 TypeAlias support.
Now that https://github.com/astral-sh/ruff/pull/20263 is merged, we can
update mypy_primer and add the new `egglog-python` project to
`good.txt`. The ecosystem-analyzer run shows that we now add 1,356
diagnostics (where we had over 5,000 previously, due to the unsupported
project layout).
## Summary
Add backreferences to the original item declaration in TypedDict
diagnostics.
Thanks to @AlexWaygood for the suggestion.
## Test Plan
Updated snapshots
## Summary
An annotated assignment `name: annotation` without a right-hand side was
previously not covered by the range returned from
`DefinitionKind::full_range`, because we did expand the range to include
the right-hand side (if there was one), but failed to include the
annotation.
## Test Plan
Updated snapshot tests
## Summary
Add support for `typing.ReadOnly` as a type qualifier to mark
`TypedDict` fields as being read-only. If you try to mutate them, you
get a new diagnostic:
<img width="787" height="234" alt="image"
src="https://github.com/user-attachments/assets/f62fddf9-4961-4bcd-ad1c-747043ebe5ff"
/>
## Test Plan
* New Markdown tests
* The typing conformance changes are all correct. There are some false
negatives, but those are related to the missing support for the
functional form of `TypedDict`, or to overriding of fields via
inheritance. Both of these topics are tracked in
https://github.com/astral-sh/ty/issues/154
Closesastral-sh/ty#456. Part of astral-sh/ty#994.
After all the foundational work, this is only a small change, but let's
see if it exposes any unresolved issues.
## Summary
Part of astral-sh/ty#994. The goal of this PR was to add correct
behavior for attribute access on the top and bottom materializations.
This is necessary for the end goal of using the top materialization for
narrowing generics (`isinstance(x, list)`): we want methods like
`x.append` to work correctly in that case.
It turned out to be convenient to represent materialization as a
TypeMapping, so it can be stashed in the `type_mappings` list of a
function object. This also allowed me to remove most concrete
`materialize` methods, since they usually just delegate to the subparts
of the type, the same as other type mappings. That is why the net effect
of this PR is to remove a few hundred lines.
## Test Plan
I added a few more tests. Much of this PR is refactoring and covered by
existing tests.
## Followups
Assigning to attributes of top materializations is not yet covered. This
seems less important so I'd like to defer it.
I noticed that the `materialize` implementation of `Parameters` was
wrong; it did the same for the top and bottom materializations. This PR
makes the bottom materialization slightly more reasonable, but
implementing this correctly will require extending the struct.
## Summary
A small set of additional tests for `TypedDict` that I wrote while going
through the spec. Note that this certainly doesn't make the test suite
exhaustive (see remaining open points in the updated list here:
https://github.com/astral-sh/ty/issues/154).
This PR adds two new `ty_extensions` functions,
`reveal_when_assignable_to` and `reveal_when_subtype_of`. These are
closely related to the existing `is_assignable_to` and `is_subtype_of`,
but instead of returning when the property (always) holds, it produces a
diagnostic that describes _when_ the property holds. (This will let us
construct mdtests that print out constraints that are not always true or
always false — though we don't currently have any instances of those.)
I did not replace _every_ occurrence of the `is_property` variants in
the mdtest suite, instead focusing on the generics-related tests where
it will be important to see the full detail of the constraint sets.
As part of this, I also updated the mdtest harness to accept the shorter
`# revealed:` assertion format for more than just `reveal_type`, and
updated the existing uses of `reveal_protocol_interface` to take
advantage of this.
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## Summary
This PR implements
https://docs.astral.sh/ruff/rules/yield-from-in-async-function/ as a
syntax semantic error
## Test Plan
<!-- How was it tested? -->
I have written a simple inline test as directed in
[https://github.com/astral-sh/ruff/issues/17412](https://github.com/astral-sh/ruff/issues/17412)
---------
Signed-off-by: 11happy <soni5happy@gmail.com>
Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
## Summary
Thread visitors through the rest of `apply_type_mapping`: callable and
protocol types.
## Test Plan
Added mdtest that previously stack overflowed.
## Summary
We have the ability to defer type inference of some parts of
definitions, so as to allow us to create a type that may need to be
recursively referenced in those other parts of the definition.
We also have the ability to do type inference in a context where all
name resolution should be deferred (that is, names should be looked up
from all-reachable-definitions rather than from the location of use.)
This is used for all annotations in stubs, or if `from __future__ import
annotations` is active.
Previous to this PR, these two concepts were linked: deferred-inference
always implied deferred-name-resolution, though we also supported
deferred-name-resolution without deferred-inference, via
`DeferredExpressionState`.
For the upcoming `typing.TypeAlias` support, I will defer inference of
the entire RHS of the alias (so as to support cycles), but that doesn't
imply deferred name resolution; at runtime, the RHS of a name annotated
as `typing.TypeAlias` is executed eagerly.
So this PR fully de-couples the two concepts, instead explicitly setting
the `DeferredExpressionState` in those cases where we should defer name
resolution.
It also fixes a long-standing related bug, where we were deferring name
resolution of all names in class bases, if any of the class bases
contained a stringified annotation.
## Test Plan
Added test that failed before this PR.
Reverts astral-sh/ruff#20156. As @sharkdp noted in his post-merge
review, there were several issues with that PR that I didn't spot before
merging — but I'm out for four days now, and would rather not leave
things in an inconsistent state for that long. I'll revisit this on
Wednesday.
## Summary
These projects all check successfully now.
(Pandas still takes 9s, as the comment in `bad.txt` said, but I don't
think this is slow enough to exclude it; mypy-primer overall still runs
in 4 minutes, faster than e.g. the test suite on Windows.)
## Test Plan
mypy-primer CI.
## Summary
This error is about assigning to attributes rather than reading
attributes, so I think `invalid-assignment` makes more sense than
`invalid-attribute-access`
## Test Plan
existing mdtests updated
## Summary
Now that we have `Type::TypeAlias`, which can wrap a union, and the
possibility of unions including non-unpacked type aliases (which is
necessary to support recursive type aliases), we can no longer assume in
`UnionType::normalized_impl` that normalizing each element of an
existing union will result in a set of elements that we can order and
then place raw into `UnionType` to create a normalized union. It's now
possible for those elements to themselves include union types (unpacked
from an alias). So instead, we need to feed those elements into the full
`UnionBuilder` (with alias-unpacking turned on) to flatten/normalize
them, and then order them.
## Test Plan
Added mdtest.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
This PR fixes various TODOs around overload call when a variadic
argument is used.
The reason this bug existed is because the specialization wouldn't
account for unpacking the type of the variadic argument.
This is fixed by expanding `MatchedArgument` to contain the type of that
argument _only_ when it is a variadic argument. The reason is that
there's a split for when the argument type is inferred -- the
non-variadic arguments are inferred using `infer_argument_types` _after_
parameter matching while the variadic argument type is inferred _during_
the parameter matching. And, the `MatchedArgument` is populated _during_
parameter matching which means the unpacking would need to happen during
parameter matching.
This split seems a bit inconsistent but I don't want to spend a lot of
time on trying to merge them such that all argument type inference
happens in a single place. I might look into it while adding support for
`**kwargs`.
## Test Plan
Update existing tests by resolving the todos.
The ecosystem changes looks correct to me except for the `slice` call
but it seems that it's unrelated to this PR as we infer `slice[Any, Any,
Any]` for a `slice(1, 2, 3)` call on `main` as well
([playground](https://play.ty.dev/9eacce00-c7d5-4dd5-a932-4265cb2bb4f6)).
