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

..

annotations

[ty] Fallback to Unknown if no type is stored for an expression (#19517)

2025-07-25 02:05:32 +00:00

assignment

[ty] Homogeneous and mixed tuples (#18600)

2025-06-20 18:23:54 -04:00

binary

[ty] Homogeneous and mixed tuples (#18600)

2025-06-20 18:23:54 -04:00

boolean

Revert "[ty] Better control flow for boolean expressions that are inside if (#18010)" (#18150)

2025-05-17 08:27:32 -04:00

boundness_declaredness

Update class literal display to use <class 'Foo'> style (#17889)

2025-05-06 20:11:25 -04:00

call

[ty] Support async/await, async with and yield from (#19595)

2025-07-30 11:51:21 +02:00

class

Update class literal display to use <class 'Foo'> style (#17889)

2025-05-06 20:11:25 -04:00

comparison

[ty] Enum literal types (#19328)

2025-07-15 21:31:53 +02:00

comprehensions

[ty] Async for loops and async iterables (#19634)

2025-07-30 17:40:24 +02:00

conditional

[ty] Exhaustiveness checking & reachability for match statements (#19508)

2025-07-23 22:45:45 +02:00

dataclasses

[ty] Add basic support for dataclasses.field (#19553)

2025-07-25 14:56:04 +02:00

declaration

[ty] Format conflicting types as an enumeration (#18956)

2025-06-26 14:29:33 +02:00

diagnostics

[ty] Async for loops and async iterables (#19634)

2025-07-30 17:40:24 +02:00

directives

[ty] Exhaustiveness checking & reachability for match statements (#19508)

2025-07-23 22:45:45 +02:00

doc

ty_python_semantic: add union type context to function call type errors

2025-05-09 13:40:51 -04:00

exception

[ty] support del statement and deletion of except handler names (#18593)

2025-06-12 07:44:42 -07:00

expression

[ty] Support async/await, async with and yield from (#19595)

2025-07-30 11:51:21 +02:00

function

[ty] Minor: test isolation (#19597)

2025-07-28 15:52:59 +02:00

generics

[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

ide_support

[ty] Enum literal types (#19328)

2025-07-15 21:31:53 +02:00

import

lint on the global keyword if there's no explicit definition in the global scope

2025-07-15 16:56:54 -07:00

literal

[ty] Understand classes that inherit from subscripted Protocol[] as generic (#17832)

2025-05-09 17:39:15 +01:00

loops

[ty] Async for loops and async iterables (#19634)

2025-07-30 17:40:24 +02:00

narrow

[ty] Attribute access on intersections with negative parts (#19524)

2025-07-25 14:56:14 +02:00

regression

Rename Red Knot (#17820)

2025-05-03 19:49:15 +02:00

scopes

[ty] improve lazy scope place lookup (#19321)

2025-07-25 07:11:11 +00:00

shadowing

Rename Red Knot (#17820)

2025-05-03 19:49:15 +02:00

snapshots

[ty] Async for loops and async iterables (#19634)

2025-07-30 17:40:24 +02:00

stubs

[ty] Do not carry the generic context of Protocol or Generic in the ClassBase enum (#17989)

2025-05-22 21:37:03 -04:00

subscript

[ty] Synthesize precise __getitem__ overloads for tuple subclasses (#19493)

2025-07-30 11:25:44 +00:00

suppressions

[ty] Consistent use of American english (in rules) (#19488)

2025-07-22 16:10:38 +02:00

type_compendium

[ty] Make tuple subclass constructors sound (#19469)

2025-07-21 21:25:11 +00:00

type_of

[ty] Enum literal types (#19328)

2025-07-15 21:31:53 +02:00

type_properties

[ty] Infer single-valuedness for enums based on int/str (#19510)

2025-07-23 15:55:42 +02:00

type_qualifiers

[ty] Support dataclasses.InitVar (#19527)

2025-07-24 16:33:33 +02:00

unary

Update class literal display to use <class 'Foo'> style (#17889)

2025-05-06 20:11:25 -04:00

with

[ty] Support async/await, async with and yield from (#19595)

2025-07-30 11:51:21 +02:00

.mdformat.toml

Rename Red Knot (#17820)

2025-05-03 19:49:15 +02:00

async.md

[ty] Support async/await, async with and yield from (#19595)

2025-07-30 11:51:21 +02:00

attributes.md

[ty] Attribute access on intersections with negative parts (#19524)

2025-07-25 14:56:14 +02:00

cycle.md

[ty] Add cycle handling for unpacking targets (#18078)

2025-05-13 21:27:48 +00:00

decorators.md

ty_python_semantic: add union type context to function call type errors

2025-05-09 13:40:51 -04:00

del.md

[ty] improve lazy scope place lookup (#19321)

2025-07-25 07:11:11 +00:00

deprecated.md

[ty] Consistent use of American english (in rules) (#19488)

2025-07-22 16:10:38 +02:00

descriptor_protocol.md

[ty] Fix descriptor lookups for most types that overlap with None (#19120)

2025-07-05 19:34:23 +01:00

enums.md

[ty] Exhaustiveness checking & reachability for match statements (#19508)

2025-07-23 22:45:45 +02:00

exhaustiveness_checking.md

[ty] Exhaustiveness checking & reachability for match statements (#19508)

2025-07-23 22:45:45 +02:00

final.md

Rename Red Knot (#17820)

2025-05-03 19:49:15 +02:00

instance_layout_conflict.md

[ty] Improve disjointness inference for NominalInstanceTypes and SubclassOfTypes (#18864)

2025-06-24 20:27:37 +00:00

intersection_types.md

[ty] Expansion of enums into unions of literals (#19382)

2025-07-21 19:37:55 +02:00

invalid_syntax.md

Rename Red Knot (#17820)

2025-05-03 19:49:15 +02:00

known_constants.md

Rename Red Knot (#17820)

2025-05-03 19:49:15 +02:00

mdtest_config.md

Rename Red Knot (#17820)

2025-05-03 19:49:15 +02:00

mdtest_custom_typeshed.md

[ty] Fix duplicate diagnostics for unresolved module when an import from statement imports multiple members (#17886)

2025-05-06 12:37:10 +01:00

metaclass.md

Update class literal display to use <class 'Foo'> style (#17889)

2025-05-06 20:11:25 -04:00

mro.md

[ty] Implement implicit inheritance from Generic[] for PEP-695 generic classes (#18283)

2025-05-26 20:40:16 +01:00

named_tuple.md

[ty] Add generic inference for dataclasses (#18443)

2025-06-03 09:59:43 -07:00

overloads.md

[ty] Add support for @staticmethods (#18809)

2025-06-20 10:38:17 +02:00

pep695_type_aliases.md

[ty] Support typing.TypeAliasType (#18156)

2025-05-19 16:36:49 +02:00

properties.md

ty_python_semantic: add union type context to function call type errors

2025-05-09 13:40:51 -04:00

protocols.md

[ty] Attribute access on intersections with negative parts (#19524)

2025-07-25 14:56:14 +02:00

public_types.md

[ty] improve lazy scope place lookup (#19321)

2025-07-25 07:11:11 +00:00

statically_known_branches.md

[ty] Infer nonlocal types as unions of all reachable bindings (#18750)

2025-06-26 12:24:40 +02:00

sys_platform.md

Rename Red Knot (#17820)

2025-05-03 19:49:15 +02:00

sys_version_info.md

Rename Red Knot (#17820)

2025-05-03 19:49:15 +02:00

terminal_statements.md

[ty] improve lazy scope place lookup (#19321)

2025-07-25 07:11:11 +00:00

ty_extensions.md

[ty] Rename type_api => ty_extensions (#19523)

2025-07-24 08:24:26 +00:00

typed_dict.md

[ty] Reduce false positives for TypedDict types (#19354)

2025-07-15 12:47:19 +01:00

union_types.md

[ty] Expansion of enums into unions of literals (#19382)

2025-07-21 19:37:55 +02:00

unpacking.md

[ty] Support variable-length tuples in unpacking assignments (#18948)

2025-06-27 15:29:04 -04:00

unreachable.md

[ty] improve lazy scope place lookup (#19321)

2025-07-25 07:11:11 +00:00