ruff/crates/ty_python_semantic/resources
Alex Waygood ec3d5ebda2
[ty] Upcast heterogeneous and mixed tuples to homogeneous tuples where it's necessary to solve a TypeVar (#19635)
## Summary

This PR improves our generics solver such that we are able to solve the
`TypeVar` in this snippet to `int | str` (the union of the elements in
the heterogeneous tuple) by upcasting the heterogeneous tuple to its
pure-homogeneous-tuple supertype:

```py
def f[T](x: tuple[T, ...]) -> T:
    return x[0]

def g(x: tuple[int, str]):
    reveal_type(f(x))
```

## Test Plan

Mdtests. Some TODOs remain in the mdtest regarding solving `TypeVar`s
for mixed tuples, but I think this PR on its own is a significant step
forward for our generics solver when it comes to tuple types.

---------

Co-authored-by: Douglas Creager <dcreager@dcreager.net>
2025-07-30 17:12:21 +01:00
..
corpus [ty] Do not consider a type T to satisfy a method member on a protocol unless the method is available on the meta-type of T (#19187) 2025-07-25 11:16:04 +01:00
mdtest [ty] Upcast heterogeneous and mixed tuples to homogeneous tuples where it's necessary to solve a TypeVar (#19635) 2025-07-30 17:12:21 +01:00
primer [ty] Move zope.interface to good.txt for primer runs (#19208) 2025-07-25 14:12:17 +01:00
README.md Rename Red Knot (#17820) 2025-05-03 19:49:15 +02:00

Markdown files within the mdtest/ subdirectory are tests of type inference and type checking; executed by the tests/mdtest.rs integration test.

See crates/ty_test/README.md for documentation of this test format.