David Peter 742f8a4ee6 [ty] Use C[T] instead of C[Unknown] for the upper bound of Self (#20479) ... ### Summary This PR includes two changes, both of which are necessary to resolve https://github.com/astral-sh/ty/issues/1196: * For a generic class `C[T]`, we previously used `C[Unknown]` as the upper bound of the `Self` type variable. There were two problems with this. For one, when `Self` appeared in contravariant position, we would materialize its upper bound to `Bottom[C[Unknown]]` (which might simplify to `C[Never]` if `C` is covariant in `T`) when accessing methods on `Top[C[Unknown]]`. This would result in `invalid-argument` errors on the `self` parameter. Also, using an upper bound of `C[Unknown]` would mean that inside methods, references to `T` would be treated as `Unknown`. This could lead to false negatives. To fix this, we now use `C[T]` (with a "nested" typevar) as the upper bound for `Self` on `C[T]`. * In order to make this work, we needed to allow assignability/subtyping of inferable typevars to other types, since we now check assignability of e.g. `C[int]` to `C[T]` (when checking assignability to the upper bound of `Self`) when calling an instance-method on `C[int]` whose `self` parameter is annotated as `self: Self` (or implicitly `Self`, following https://github.com/astral-sh/ruff/pull/18007). closes https://github.com/astral-sh/ty/issues/1196 closes https://github.com/astral-sh/ty/issues/1208 ### Test Plan Regression tests for both issues.		2025-09-23 14:02:25 +02:00
..
annotations	[ty] Bind Self typevar to method context (#20366)	2025-09-17 14:58:54 -04:00
assignment	re-infer RHS of annotated assignments in isolation for assignability diagnostics	2025-09-19 17:00:37 -04:00
binary	[ty] Remove special casing for string-literal-in-tuple __contains__ (#19642)	2025-07-31 11:28:03 +01:00
boolean
boundness_declaredness
call	[ty] Add support for **kwargs (#20430)	2025-09-19 05:00:30 +00:00
class	[ty] Remove use of ClassBase::try_from_type from super() machinery (#19902)	2025-08-14 22:14:31 +01:00
comparison	[ty] detect cycles in binary comparison inference (#20446)	2025-09-17 09:45:25 +02:00
comprehensions	[ty] Async for loops and async iterables (#19634)	2025-07-30 17:40:24 +02:00
conditional	[ty] Support as-patterns in reachability analysis (#19728)	2025-08-04 20:13:50 +02:00
dataclasses	[ty] initial support for slots=True in dataclasses (#20278)	2025-09-07 18:25:35 +01:00
declaration
diagnostics	[ty] Improve specialization-error diagnostics (#20326)	2025-09-10 14:01:23 +02:00
directives	[ty] Infer slightly more precise types for comprehensions (#20111)	2025-08-27 13:21:47 +01:00
doc
exception	[ty] Use separate Rust types for bound and unbound type variables (#19796)	2025-08-11 15:29:58 -04:00
expression	[ty] Proper assignability/subtyping checks for protocols with method members (#20165)	2025-09-12 10:10:31 +00:00
function	[ty] Improve disambiguation of types via fully qualified names (#20141)	2025-08-29 08:44:18 +00:00
generics	[ty] Use C[T] instead of C[Unknown] for the upper bound of Self (#20479)	2025-09-23 14:02:25 +02:00
ide_support	[ty] Include NamedTupleFallback members in NamedTuple instance completions (#20356)	2025-09-15 11:00:03 +02:00
import	[ty] Infer more precise types for collection literals (#20360)	2025-09-17 18:51:50 -04:00
literal	[ty] Infer more precise types for collection literals (#20360)	2025-09-17 18:51:50 -04:00
loops	[ty] Add precise iteration and unpacking inference for string literals and bytes literals (#20023)	2025-08-22 19:33:08 +01:00
narrow	[ty] Use C[T] instead of C[Unknown] for the upper bound of Self (#20479)	2025-09-23 14:02:25 +02:00
regression
scopes	[ty] fix deferred name loading in PEP695 generic classes/functions (#19888)	2025-08-13 15:51:59 -07:00
shadowing
snapshots	[ty] Improve specialization-error diagnostics (#20326)	2025-09-10 14:01:23 +02:00
stubs
subscript	[ty] Infer more precise types for collection literals (#20360)	2025-09-17 18:51:50 -04:00
suppressions
type_compendium	[ty] Infer more precise types for collection literals (#20360)	2025-09-17 18:51:50 -04:00
type_of	[ty] Improve the Display for generic type[] types (#19667)	2025-07-31 19:45:01 +01:00
type_properties	[ty] Fix class literal subtyping with object fallback (#20521)	2025-09-22 17:26:25 -07:00
type_qualifiers	[ty] Allow annotation expressions to be ast::Attribute nodes (#20413)	2025-09-15 12:06:48 +01:00
unary
with	[ty] Diagnostics for async context managers (#19704)	2025-08-05 07:41:37 -07:00
.mdformat.toml
async.md	[ty] Support async/await, async with and yield from (#19595)	2025-07-30 11:51:21 +02:00
attributes.md	[ty] infer name and value for enum members (#20311)	2025-09-17 09:36:27 +02:00
classes.md	[ty] don't assume that deferred type inference means deferred name resolution (#20160)	2025-08-29 16:19:45 -07:00
cycle.md
decorators.md
del.md	[ty] Infer more precise types for collection literals (#20360)	2025-09-17 18:51:50 -04:00
deprecated.md
descriptor_protocol.md	[ty] "foo".startswith is not an instance of types.MethodWrapperType (#20317)	2025-09-10 11:14:26 +00:00
enums.md	[ty] implement auto() for StrEnum (#20524)	2025-09-23 12:22:59 +02:00
exhaustiveness_checking.md	[ty] Narrow specialized generics using isinstance() (#20256)	2025-09-04 15:28:33 -07:00
final.md
implicit_type_aliases.md	[ty] no more diverging query cycles in type expressions (#20359)	2025-09-16 16:44:11 -07:00
instance_layout_conflict.md	[ty] initial support for slots=True in dataclasses (#20278)	2025-09-07 18:25:35 +01:00
intersection_types.md
invalid_syntax.md
known_constants.md
mdtest_config.md
mdtest_custom_typeshed.md	[ty] Remove Type::Tuple (#19669)	2025-08-11 22:03:32 +01:00
metaclass.md
mro.md	[ty] Treat Hashable, and similar protocols, equivalently to object for subtyping/assignability (#20284)	2025-09-10 11:38:58 +01:00
named_tuple.md	[ty] Patch Self for fallback-methods on NamedTuples and TypedDicts (#20328)	2025-09-15 16:21:53 +02:00
overloads.md	[ty] Use C[T] instead of C[Unknown] for the upper bound of Self (#20479)	2025-09-23 14:02:25 +02:00
pep695_type_aliases.md	[ty] detect cycles in binary comparison inference (#20446)	2025-09-17 09:45:25 +02:00
properties.md	[ty] "foo".startswith is not an instance of types.MethodWrapperType (#20317)	2025-09-10 11:14:26 +00:00
protocols.md	[ty] The runtime object typing.Protocol is an instance of _ProtocolMeta (#20488)	2025-09-22 08:29:03 +01:00
public_types.md	[ty] more precise lazy scope place lookup (#19932)	2025-09-08 21:08:35 +00:00
statically_known_branches.md	[ty] Evaluate reachability of non-definitely-bound to Ambiguous (#19579)	2025-08-28 14:34:49 +02:00
sys_platform.md
sys_version_info.md
t_strings.md	[ty] Add support for PEP 750 t-strings (#20085)	2025-08-25 18:49:49 +00:00
terminal_statements.md
ty_extensions.md	[ty] Fix CallableTypeOf[…] for classmethods (#20345)	2025-09-11 10:14:38 +02:00
typed_dict.md	[ty] Patch Self for fallback-methods on NamedTuples and TypedDicts (#20328)	2025-09-15 16:21:53 +02:00
union_types.md	[ty] Simplify unions of enum literals and subtypes thereof (#20324)	2025-09-10 15:54:06 +02:00
unpacking.md	[ty] Infer more precise types for collection literals (#20360)	2025-09-17 18:51:50 -04:00
unreachable.md