ty

Release Notes

Released on 2026-09-21.

Bug fixes

• Fix hangs from repeated partial application (#28754)
• Preserve PEP 695 bindings across nested classes (#28723)

LSP server

• Include required imports in every inlay hint (#28724)
• Preserve fast name filtering for normalized Unicode source (#28701)
• Refresh diagnostics after workspace configuration changes (#28755)

Diagnostic improvements

• Expand unreachable-code annotations for redundant conditions (#28674)
• Improve diagnostics for async generator stubs (#28692)
• Improve primary diagnostic annotations for redundant-condition(-strict) diagnostics (#28666)
• Point misplaced tuple ellipsis diagnostics at each ellipsis (#28709)

Other changes

• Add rules that detect suspicious uses of Callable, Iterable, Iterator or Generator types in a boolean context (#28554)
• Allow slots to override abstract properties (#28698)
• Avoid leaking Unknown from unconstrained collection use-sites (#28659)
• Diagnose unguarded cycles in implicit and PEP 613 aliases (#28704)
• Eagerly bind unused Self receivers (#28662)
• Generalize receiver binding for wrapped callables (#28725)
• More faithful representation of bound methods (#28410)
• Only classify evidence bounds for constrained type variables (#28700)
• Preserve inferred bindings during annotation cycles (#28717)
• Preserve quoted aliases during cycle recovery (#28710)
• Reject class-scoped type variables in init receivers (#28706)
• Reject unsafe TypedDict updates from hidden fields (#28711)
• Respect fixed caller type variables when selecting constraints (#28652)
• Reuse cached type alias inference for diagnostics (#28696)
• Simplify unions of disjoint exclusions (#28684)
• Update typing conformance suite (#28718)

Contributors

• @charliermarsh
• @AlexWaygood
• @sharkdp
• @carljm
• @ibraheemdev
• @zaniebot
• @MichaReiser

Install ty 0.0.83

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.83/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.83/ty-installer.ps1 | iex"

Download ty 0.0.83

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-09-17.

Preview features

• Ignore Python version from uv metadata (#28646)
• Watch script dependencies in CLI watch mode (#28125)

CLI

• Only skip uv workspace metadata for a single script (#28581)
• Support dependency lints with --config-file (#28573)

LSP server

• Filter string literal completions by typed text (#28612)
• Find member references across files (#28669)
• Find parameter references across files (#28670)
• Preserve valid LSP settings when configuration resolution fails (#28653)
• Reuse identifier matcher in LSP operations (#28663)
• Watch script dependencies in the language server (#28522)

Diagnostic improvements

• Add an autofix for unused awaitables (#28668)
• Add annotations for unreachable code caused by boolean operands (#28521)
• Add subdiagnostics to redundant-condition rules warning about reachability implications (#28263)
• Clarify diagnostics for unimplemented abstract members (#28538)
• Extend unreachable-code annotations to while, assert, and match statements (#28290)

Core type checking

• Allow experimental intersection syntax in PEP 695 aliases (#28513)
• Bound aliased intersection expansion during inference (#28546)
• Check declared variance against final method bindings (#28155)
• Fix recursive protocol checks for decorated methods (#28293)
• Freshen constructor-owned Self with class type variables (#28592)
• Improve disjointness of functools.partial types (#28660)
• Include constraint-set assignability in more checks (#28642)
• Infer conditional literals from peers in unspecialized contexts (#28633)
• Infer generic elements from gradual tuples (#28637)
• Introduce Recursive types and fully support recursive implicit type aliases (#28425)
• Narrow type context during tuple inference (#28658)
• Preserve field metadata after overload resolution (#28635)
• Preserve gradual class assignability in constraint-set checks (#28638)
• Preserve gradual tuple lengths during callable inference (#28588)
• Preserve tuple shapes during concatenation (#28617)
• Reject abstract class instantiation (#28167)
• Respect frozen=False overrides on Pydantic subclasses (#28515)
• Support type[A & B] (#27124)
• Sync vendored typeshed stubs (#28597). Typeshed diff
• Treat imports as bindings instead of declarations (#27325)

Performance

• Compact reachable binding and declaration histories (#28349)
• Compare bound-method receivers before signatures (#28384)
• Deduplicate intermediate intersection branches (#28649)
• Optimize fuel management in the constraint solver (#28568)
• Skip inferring concrete methods during abstract-method discovery (#28613)
• Skip legacy namespace parsing for __init__ files without pkg (#28665)

Memory usage improvements

• Avoid storing constraint nodes twice (#28375)

Contributors

• @mtshiba
• @zsol
• @AlexWaygood
• @charliermarsh
• @woodruffw
• @carljm
• @MichaReiser
• @sharkdp
• @ibraheemdev

Install ty 0.0.82

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.82/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.82/ty-installer.ps1 | iex"

Download ty 0.0.82

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-09-14.

Bug fixes

• Escape glob characters in anchored directory paths (#28518)
• Ignore divergent markers when detecting descriptors (#28514)

CLI

• Anchor default exclude patterns at the project root (#28463)

Core type checking

• Avoid rebinding extracted method calls (#28469)
• Default-specialize class objects in meta-protocol checks (#28265)
• Fix MRO ordering for generic bases (#28172)
• Fix assignability of bounded typevars to intersection types (#28479)
• Fix variadic partial signature reduction (#28586)
• Handle gradual metaclass ancestry and conflicts (#28474)
• Preserve recursive metadata in union transformations (#28497)
• Preserve runtime comparison semantics when narrowing tagged unions (#28053)
• Preserve wrapped signatures in nominal descriptor checks (#28466)
• Reject reassignment of enum members (#28462)
• Report override conflicts introduced by new bases (#28530)
• Resolve dependencies within correlated inference alternatives (#28252)
• Respect instance dictionary storage for slotted classes (#27749)
• Validate explicitly overridden constructor signatures (#28115)

Performance

• Avoid redundant superclass member inference (#28587)
• Reuse rendered union elements when displaying types (#28494)

Memory usage improvements

• Reduce retained AST memory by shrinking expressions (#28335)
• Share strings in dependency metadata (#28141)

Contributors

• @sharkdp
• @ibraheemdev
• @MichaReiser
• @zsol
• @zanieb
• @charliermarsh
• @mtshiba
• @carljm

Install ty 0.0.81

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.81/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.81/ty-installer.ps1 | iex"

Download ty 0.0.81

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-09-09.

Bug fixes

• Fix --force-exclude for directories with an excluded ancestor (#28451)
• Preserve metaclass candidates after conflicts (#28461)

LSP server

• Give existing autofixes descriptive titles (#28456)
• Prevent LSP hangs during inlay hint bursts (#28390)

Diagnostic improvements

• Preserve redundant-condition diagnostics with unreachable operands (#28374)

Core type checking

• Check captured receivers when calling wrapped classmethods (#28467)
• Fix cached classmethods on generic classes (#28207)
• Fix disjointness of type guards and boolean literals (#28363)
• Infer tuple variance from the full tuple spec (#28446)
• Infer tuple variance more precisely (#28426)
• Preserve callable identity across specialized types (#28409)
• Preserve callback type context through ParamSpec forwarding (#28439)
• Preserve wrapped functions in precise functools.partial relations (#28460)
• Respect descriptor protocol for __set__ itself (#28408)
• Respect type-variable bounds in argument context (#28448)
• Unwrap union alternatives in overload implementations (#28468)

Performance

• Distribute len inference over unions (#28470)
• Fast-path concrete literal intersections (#28348)

Memory usage improvements

• Avoid excess capacity in multi-binding tables (#28412)
• Share equivalent place tables within a file (#28319)
• Share names in synthesized constructor parameters (#28398)

Contributors

• @sharkdp
• @charliermarsh
• @ibraheemdev
• @AlexWaygood
• @MichaReiser

Install ty 0.0.80

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.80/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.80/ty-installer.ps1 | iex"

Download ty 0.0.80

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-09-07.

Bug fixes

• Avoid dict keyword-call panics when typing is shadowed (#28292)
• Discover configs in models derived from legacy generic classes (#28397)
• Normalize recursive collection-use constraints (#28332)
• Recover cycles when constructing known class instances (#28289)

CLI

• Embed archive checksums in the shell installer (#4458)

Diagnostic improvements

• Add Literal fixes for diagnostics flagging invalid type annotations (#28185)
• Add await fixes for redundant conditions (#28169)
• Add assert_never fixes for redundant final elif branches (#28178)
• Add defensive assertion fallback for redundant elif fixes (#28179)
• Add rules to detect always-truthy and always-falsy conditions (#28034)
• Preserve deprecations on decorated callables (#28256)
• Require a direct dependency for reveal_type backport fixes (#28177)
• Suggest variable-length tuple annotations for redundant conditions (#28168)

Core type checking

• Align TypeIs and isinstance narrowing (#28193)
• Avoid falling back to Unknown when collecting type context constraints (#28297)
• Ensure f is identity(f) evaluates to Literal[True] (#28360)
• Fix callable specialization with union-valued ParamSpec (#28085)
• Infer variance through recursive protocols (#28077)
• Narrow types with ordered length comparisons (#28264)
• Preserve gradual type context during generic call inference (#28091)
• Preserve nominal subtyping for top-materialized protocols (#28271)
• Preserve outer type variables during ParamSpec inference (#28306)
• Preserve protocol intersections when narrowing gradual types (#28391)
• Promote literals in nested (non-covariant) positions (#28389)
• Reject missing attributes on type[] aliases (#28267)
• Solve formal unions using constraint-sets (#28312)
• Sync vendored typeshed stubs (#28331). Typeshed diff

Performance

• Avoid unnecessary work when building specializations (#28369)
• Bypass materialization queries for simple types (#28367)
• Cache exception suppression for context managers (#28376)
• Intern statement call predicates (#28373)
• Lazily compute argument-context specializations (#28378)
• Pre-size packed AST index chunks (#28372)
• Reduce repeated work in use-def merges (#28365)
• Skip decorator flags query for undecorated methods (#28338)

Memory usage improvements

• Avoid caching simple type specializations (#28333)
• Box cached MRO error details (#28351)
• Reuse generic aliases as MRO query keys (#28350)
• Reuse interned bound method signatures (#28346)
• Reuse stored function signatures without caching duplicates (#28347)
• Share retained use-def tables across scopes (#28313)
• Store single narrowing operations inline (#28345)
• Store uncommon signature metadata out of line (#28339)

Other changes

• Declare support for Python 3.15 (#4476)

Contributors

• @carljm
• @sharkdp
• @charliemarsh-oai
• @zsol
• @charliermarsh
• @ibraheemdev
• @AlexWaygood

Install ty 0.0.79

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.79/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.79/ty-installer.ps1 | iex"

Download ty 0.0.79

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-09-02.

Bug fixes

• Defer decorator-call diagnostics to avoid recursive-default cycles (#28226)
• Make cyclic intersection simplification deterministic (#28156)
• Stabilize cyclic terminal-call reachability (#28216)

Preview features

• Refresh uv workspace metadata when dependencies change (#28224)

Diagnostics

• Add a new disjoint-cast rule (#28129)
• Report deprecated property accessors on intersections (#28250)
• Report deprecations for implicit constructor calls (#28251)
• Report deprecations for overloads, operators, and properties (#28134)
• Respect overload selection in deprecation diagnostics (#28148)

Core type checking

• Fix negative narrowing for protocols with gradual members (#28198)
• Preserve ParamSpec bindings inferred against type context (#28084)
• Preserve generic protocol materialization relations (#28246)
• Preserve uncertain branches during quantification (#28211)
• Respect type variables in top/bottom materializations of invariant generics (#28072)
• Sync vendored typeshed stubs (#28217). Typeshed diff
• Treat captured bound-method receivers covariantly (#28180)
• Unsound intersection simplification for generic iterables (#28068)
• Validate type variable scopes in constructors and aliases (#28130)
• lambda functions are always truthy (#28254)

Performance

• Optimize materialized recursive protocol comparisons (#28079)
• Optimize recursive protocol checks for nested type variables (#28257)

Contributors

• @charliermarsh
• @sharkdp
• @zsol
• @AlexWaygood
• @ibraheemdev
• @carljm

Install ty 0.0.78

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.78/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.78/ty-installer.ps1 | iex"

Download ty 0.0.78

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-08-31.

Bug fixes

• Bound recursive protocol traversal in generic intersections (#28215)
• Preserve recursion guards across nested type operations (#28150)
• Preserve syntax and comments when removing redundant casts (#28145)
• Stabilize recursive receiver inference (#28042)
• Stabilize condition truthiness during cyclic inference (#28212)

Core type checking

• Preserve generic receivers in implicit __init_subclass__ calls (#28138)
• Preserve specialization for inherited TypedDict methods (#28111)
• Propagate deletions through nested loop headers (#28044)

Performance

• Avoid repeated inference for literal union call results (#28196)

Contributors

• @charliermarsh
• @carljm

Install ty 0.0.77

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.77/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.77/ty-installer.ps1 | iex"

Download ty 0.0.77

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-08-31.

Preview features

• Add a missing-direct-dependency rule (#28001)
• Cancel superseded queued uv requests (#28108)
• Check direct dependencies in PEP 723 scripts (#28136)
• Fix Goto definition in script dependencies (#27747)
• Move script environment initialization to the CLI and LSP (#28038)
• Refresh uv project metadata in the background (#27933)
• Synchronize PEP 723 script environments in the language server (#27619)
• Warn when uv metadata cannot support dependency checks (#28133)

Bug fixes

• Avoid panics on incomplete protocol type parameter lists (#28088)
• Fix auto-completion panic involving bare declarations (#28191)
• Guard recursive meta-type expansion (#28143)
• Preserve parentheses when removing redundant casts (#28092)

LSP server

• Add "Find references" support for pytest fixtures (#28075)
• Highlight PEP 723 script metadata as TOML (#27746)
• Synchronize saved script metadata on open (#27873)

Core type checking

• Apply mixin specialization when validating enum members (#28101)
• Bind Self through generic type aliases (#28117)
• Infer lambda parameters through callable type aliases (#28109)
• Intersection simplifications with subtype-related generic specializations (#26880)
• Invalidate member narrowing across loop iterations (#28009)
• Narrow functional enum members in == and match (#28103)
• Only treat recursive types with unbounded specializations as fallback cycles (#27538)
• Preserve Final variance in stubs (#28119)
• Preserve inferred types for unknown class-decorator results (#28067)
• Preserve list literal positions in starred unpacking (#28061)
• Preserve short-circuit reachability for direct conditions (#28082)
• Preserve type variables in bounded generic defaults (#28122)
• Reject circular type alias definitions (#28140)
• Reject class access to generic instance attributes (#28123)
• Use the subclass receiver when checking method overrides (#28124)
• Validate declared variance in method signatures (#28116)

Performance

• Avoid cubic narrowing with repeated assignments and context managers (#27787)
• Avoid repeated traversal of shared alias arguments (#28147)
• Reject impossible eager protocol comparisons early (#28081)

Contributors

• @AlexWaygood
• @MichaReiser
• @charliermarsh
• @BitWeaverDev
• @gorewilliams
• @zsol
• @malkin0xb8
• @sharkdp
• @mtshiba
• @carljm
• @lerebear
• @jamtat

Install ty 0.0.76

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.76/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.76/ty-installer.ps1 | iex"

Download ty 0.0.76

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-08-26.

Preview features

• Initialize PEP 723 script environments in the CLI (#27544)
• Refresh PEP 723 script environments in watch mode (#27617)
• Run PEP 723 script synchronization on bounded workers (#27615)

Bug fixes

• Specialize Self bounds of inherited methods (#27990)

LSP server

• Add "Go to Definition" support for pytest fixtures (#27444)

Documentation

• Fix documented Python package build command (#4384)
• Link untyped-call tracking issue in migration guide (#4382)

Library support

• Resolve imported pytest fixture exposures (#27539)
• Resolve installed core pytest fixture providers (#27770)
• Resolve pytest fixtures through conftest (#27540)

Diagnostics

• Add more autofixes (#28029)
• Add a dedicated missing-slot diagnostic (#28039)
• Explain missing storage for declared slotted attributes (#27969)
• Improve diagnostic spans for unpacked variable assignments (#28041)

Core type checking

• Account for known subclasses in equality inference (#28005)
• Expand ParamSpec signatures inferred from bound receivers (#28020)
• Fix Self binding in ParamSpec protocols (#28016)
• Fix TypedDict variance inference (#28052)
• Fix unsound narrowing through branch-assigned conditions (#28006)
• Ignore inconsistent binding decorators on overloads (#28036)
• Infer yield from send/return types from the iterator returned by __iter__ (#27987)
• Infer tuple type parameters from union arguments (#28062)
• Infer variance through nonrecursive protocol references (#28065)
• Preserve bounds of non-literal metaclasses (#28046)
• Preserve correlated generic-call inference (#28043)
• Preserve invariant materialization constraints (#28047)
• Recover bare TypeVarTuples in tuple annotations (#27950)
• Reject fixed tuples for non-inferable TypeVarTuples (#27943)
• Reject incompatible constructor context for variadic packs (#27966)
• Support mixed gradual tuple assignability with TypeVarTuple (#27957)
• Support tagged union with multiple tags per type (#27984)
• Sync vendored typeshed stubs (#28035). Typeshed diff
• Treat typing.Union as a class on Python 3.14+ (#28003)
• Validate generic protocol variance (#27531)
• collections.abc.Callable is an instance of type (#27991)

Contributors

• @sharkdp
• @jelle-openai
• @marcelo-souzaf
• @AlexWaygood
• @krzkaczor
• @carljm
• @charliermarsh
• @lerebear
• @MichaReiser

Install ty 0.0.75

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.75/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.75/ty-installer.ps1 | iex"

Download ty 0.0.75

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-08-22.

Bug fixes

• Avoid duplicate bindings in multi-target assignments (#27938)
• Avoid panic on unpacked kwargs in string annotations (#27963)
• Fix stack overflow in recursive TypedDict dictionary compatibility (#27951)
• Handle assignment expressions in string annotations (#27921)
• Handle dynamic classes in string annotations (#27883)
• Preserve string annotation context in lambda defaults and TypedDict types (#27914)
• Skip invalid subscript arguments in string annotations (#27917)
• Skip invalid subscript operands in string annotations (#27882)

LSP server

• Add untrustedWorkspace option to the LSP (#27828)
• Add executable discovery to the server command (#27806)
• Handle file-valued workspace folders from Zed (#27836)
• Skip scripts with an invalid PEP 723 configuration (#27505)
• Support pull diagnostics for notebook cells (#27778)

Documentation

• Update mypy/pyright comparison table (#4165)

Diagnostics

• Add an opt-in unsound-assignment rule for variables (#27874)
• Fix variadic signature display (#27869)
• Highlight declarations in invalid-assignment diagnostics (#27872)
• Improve LiteralString suggestions in string annotations (#27931)
• Use invalid-type-form for non-generic class annotations (#27889)

Core type checking

• Add bounded constraint solution projections (#27949)
• Fix invariant gradual tuple materialization ranges (#27946)
• Guard recursive constructor bindings by receiver (#27958)
• Preserve all alternatives in bounded intersections (#27898)
• Preserve keyword safety for unpacked callables (#27517)
• Preserve source protocol members and classify finite aliases (#27772)
• Preserve type-variable order when reloading constraints (#27904)
• Propagate narrowing through statically known branches (#27752)
• Recognize ABC metaclass methods on protocols (#27897)
• Support __slots__ (#27730)

Performance

• Lazily infer function parameter default types (#27857)
• Optimize inherited recursive protocol comparisons (#27922)
• Traverse shared constraint source-order nodes once (#27947)

Contributors

• @carljm
• @lerebear
• @charliermarsh
• @dhruvmanila
• @AlexWaygood
• @MichaReiser
• @jelle-openai

Install ty 0.0.74

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.74/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.74/ty-installer.ps1 | iex"

Download ty 0.0.74

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-08-18.

LSP server

• Do not prefer unsafe fixes in the language server (#27822)
• Fix signature help in trailing whitespace (#27784)

Library support

• Preserve variadic generics in functools.partial (#27774)

Diagnostics

• Add an opt-in rule flagging function decorators that transform a non-dynamic type into a dynamic type (#27829)
• Disambiguate same-named types in several diagnostics (#27814)
• Show error spans for errors originating in script metadata (#26693)

Core type checking

• Avoid bypassing solver during literal promotion (#27763)
• Expand nested union aliases when finding a TypedDict or callable (#27740)
• Implement intersection meta-type projection (#27660)
• Infer generic protocols from class objects (#27812)
• Model exception-suppressing context managers (#27219)
• Preserve TypeAliasType runtime origin (#27813)
• Preserve class objects in lazy protocol checks (#27815)
• Preserve declared types in exception handlers (#27817)
• Preserve explicit globals after conditional rebinding (#27786)
• Preserve property subclass types and accessors (#27833)
• Preserve required stub fields in generated constructors (#27765)
• Preserve static upper bounds of gradual solutions (#27664)
• Prevent unrelated quantified constraints from destabilizing recursive queries (#27737)
• Separate generic constraint accumulation from legacy projection (#27743)
• Simplify generic protocol inference (#27819)
• Specialize inherited members of unspecialized generic classes (#27658)
• Specialize type variables determined by bound receivers (#27732)
• Support unpacking tuple type aliases (#27825)
• Sync vendored typeshed stubs (#27771). Typeshed diff

Performance

• Cache py.typed contents (#27805)
• Deduplicate exception checkpoints across equivalent branches (#27703)

Contributors

• @charliermarsh
• @AlexWaygood
• @MichaReiser
• @augustelalande
• @carljm
• @woodruffw
• @dhruvmanila
• @ibraheemdev
• @zaniebot

Install ty 0.0.73

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.73/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.73/ty-installer.ps1 | iex"

Download ty 0.0.73

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-08-14.

Preview features

• Check PEP 723 scripts in isolation (#27462)

Library support

• Pydantic: Accept documented boolean and fractional inputs (#27754)
• Pydantic: Accept enum members for lax string and integer fields (#27751)

Diagnostics

• Improve assignability hints for protocols and TypedDict types (#27717)

Core type checking

• Avoid treating augmented assignments as attribute definitions (#27633)
• Diagnose invalid module-level __getattr__ calls (#27507)
• Fix overload argument expansion with unpacked positional arguments (#27744)
• Fix specialization of generic TypedDict aliases (#27760)
• Ignore generic declaration metadata in staticness checks (#27692)
• Preserve tuple types containing Never (#27580)
• Report deprecated unary operations (#27584)
• Respect variance when inferring structural and callable types (#27707)
• Support TypeVarTuple in call binding (#26886)
• Treat generator-expression exceptions as eagerly evaluated (#27735)

Performance

• Avoid exponential narrowing of gradual string-literal unions (#27742)

Contributors

• @AlexWaygood
• @Andrej730
• @charliermarsh
• @MichaReiser
• @dhruvmanila
• @carljm

Install ty 0.0.72

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.72/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.72/ty-installer.ps1 | iex"

Download ty 0.0.72

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-08-12.

Library support

• Respect third-party keyword-only fields before Python 3.10 (#27699)

Diagnostics

• Diagnose invalid __getattribute__ calls (#27506)
• Validate boolean conversion in comprehension filters (#27641)
• Validate unpacked callable argument shapes (#27516)

Core type checking

• Avoid introducing boolean literals when narrowing integers (#27698)
• Fix truthiness inference for subclassable known classes (#27638)
• Handle class objects that may be descriptors (#26687)
• Infer type variables through nominal type[...] parameters (#27689)
• Model exception flow with operation checkpoints (#27471)
• Preserve constrained TypeVar types when slicing (#27645)
• Preserve enum attributes on Self and bounded type variables (#27644)
• Preserve enum exhaustiveness with custom _missing_ methods (#27700)
• Preserve literal-string origin in comparison narrowing (#27582)
• Resolve generic type aliases subscripted inside type[] (#27663)
• Restrict equality impossibility to static bounds (#27655)

Performance

• Avoid deriving sequents for type variables with concrete bounds (#27587)

Contributors

• @dcreager
• @augustelalande
• @charliermarsh
• @carljm
• @AlexWaygood
• @ibraheemdev

Install ty 0.0.71

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.71/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.71/ty-installer.ps1 | iex"

Download ty 0.0.71

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-08-10.

LSP server

• Enable and downrank auto-import completions from stub-only modules (#27433)
• Fix signature help at end of file (#27622)
• Normalize type labels in structured docstrings (#26923)
• Preserve typing-only completion ranking in TYPE_CHECKING blocks (#27549)

CLI

• Avoid deadlock when scheduling watch checks (#27605)

Diagnostics

• Add an opt-in unsound-return-statement lint (#27561)
• Add an opt-in unsound-yield lint (#27593)
• Diagnose invalid __getattr__ calls (#27502)
• Diagnose invalid descriptor __get__ calls (#27400)

Core type checking

• Consider object members in protocol comparisons (#27532)
• Exclude quantified constraints from semantic type walks (#27613)
• Expand Generator aliases when evaluating return, send, and yield types (#27577)
• Infer precise TypedDict key-membership truthiness (#27579)
• Infer variance through type[T] (#27534)
• Preserve contextual inference for declarations in loops (#27594)
• Recognize overlapping NewType types and their underlying values (#27522)
• Require ClassVar declarations for protocol members (#27530)
• Stabilize recursive gradual type alias materialization (#27563)
• Support Annotated inside type[...] (#27629)
• Validate augmented assignment stores (#27545)

Contributors

• @AlexWaygood
• @carljm
• @charliermarsh
• @MichaReiser
• @lerebear

Install ty 0.0.70

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.70/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.70/ty-installer.ps1 | iex"

Download ty 0.0.70

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-08-06.

Core type checking

• isinstance narrowing for generic classes is now more gradual by default (#27308)

  This new behavior is more similar to what other major type checkers do. For example:

  def f(xs: object):
      if isinstance(xs, list):
          reveal_type(xs)  # now: `list[Unknown]`, before: `Top[list[Unknown]]`

  Note: you might consider enabling analysis.strict-generic-narrowing
  if you prefer the strictly correct behavior.

Contributors

• @sharkdp

Install ty 0.0.69

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.69/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.69/ty-installer.ps1 | iex"

Download ty 0.0.69

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-08-05.

Diagnostics

• Preserve property getter call errors (#27509)
• Simplify numeric tower displays (e.g., float over int | float) (#27406)
• Suggest closing open TypedDict types for Mapping compatibility (#27512)

Core type checking

• Avoid double inference of Unpack operands in Union (#27525)
• Fix panic from mismatched OR-pattern bindings (#27533)

Contributors

• @AlexWaygood
• @charliermarsh
• @carljm

Install ty 0.0.68

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.68/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.68/ty-installer.ps1 | iex"

Download ty 0.0.68

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-08-05.

LSP server

• Fix unused hints for OR-pattern captures (#27438)
• Index match-pattern bindings as symbols (#27260)
• Retain typing-only symbols in explicit completions (#27435)

Diagnostics

• Preserve called types in intersection diagnostics (#27475)
• Suppress unimported-reveal diagnostics in stub files and if TYPE_CHECKING blocks (#27508)

Configuration

• Remove deprecated src.root setting in favor of environment.root (#27456)

Core type checking

• Check property compatibility when matching class objects to protocols (#27402)
• Fix constructor calls on narrowed type-variable intersections (#27493)
• Fix specialization cycle with deferred TypeVar defaults (#27453)
• Infer generic TypedDicts from unpacked TypedDicts (#27439)
• Infer generic TypedDicts through synthesized constructor signatures (#27436)
• Normalize unpacked callable signatures for assignability (#27450)
• Preserve class type parameters through generic decorators (#27442)
• Preserve generic class type variables in constructor inference (#27340)
• Preserve return constraints for object-variadic callables (#27431)
• Preserve return constraints for top callables (#27446)
• Recover generic constructor types from failing overloads (#27460)
• Reject Self with incompatible explicit receiver annotations (#27454)
• Reject unhashable objects for Hashable protocols (#27441)
• Reject unsupported dataclass_transform parameters (#27458)
• Restore bottom callable subtyping for gradual prefixes (#27519)
• Top-materialize is_dataclass type guard (#27455)
• Validate constructor calls on unbounded type variables (#27449)

Performance

• Avoid exponential slowdown copying narrowed TypedDict unions (#27492)

Contributors

• @Punisheroot
• @dhruvmanila
• @AlexWaygood
• @sharkdp
• @MichaReiser
• @carljm
• @charliermarsh

Install ty 0.0.67

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.67/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.67/ty-installer.ps1 | iex"

Download ty 0.0.67

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-08-03.

LSP server

• Index with-statement targets as symbols (#27256)
• Trigger signature help after completing callable with parentheses (#27084)

Library support

• Pydantic: Recognize models installed on extra search paths (#27429)

Diagnostics

• Detect __aenter__ and __aexit__ that do not return awaitables (#27414)
• Diagnose dataclass fields after inherited defaults (#27327)
• Emit diagnostic when specializing a non-generic class (#26883)
• Improve error context for incompatible callable signatures (#27422)
• Preserve forwarded expanded-variadic diagnostic sources (#27266)

Core type checking

• Avoid over-materializing user-defined TypeIs return types (#26864)
• Fix enum class container assignability (#27318)
• Hide stub-only helpers from implicit builtin lookup (#27423)
• Move Unknown out of the experimental ty_extensions API (#27430)
• Preserve TypeVarTuple context during Generic recovery (#27381)
• Preserve exact numeric types in covariant collections (#27311)
• Reject ClassVar and Final qualifiers in NamedTuple fields (#27380)
• Reject out-of-scope ParamSpec components (#27378)
• Reject specializing non-generic subclasses (#27377)
• Respect bounds and constraints in generic materializations (#27228)
• Sync vendored typeshed stubs (#27401). Typeshed diff

Contributors

• @dhruvmanila
• @carljm
• @Punisheroot
• @AlexWaygood
• @cheparity
• @BitWeaverDev
• @charliermarsh
• @ribru17
• @sharkdp

Install ty 0.0.66

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.66/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.66/ty-installer.ps1 | iex"

Download ty 0.0.66

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-07-29.

LSP server

• Support comprehension walruses in IDE features (#26476)

Library support

• Pydantic: Allow mutation of private attributes on frozen models (#27257)
• Pydantic: Synthesize __replace__ for models (#27220)

Diagnostics

• Correct ParamSpec forwarded-argument diagnostic locations (#27263)
• Recover forwarded callable object and constructor sources (#27264)
• Recover forwarded functools.partial diagnostic sources (#27265)

Core type checking

• Fix gradual class assignability with generic receivers (#27223)
• Lazily materialize protocol attributes (#27267)
• Narrow tagged unions through all type kinds (#27226)
• Prefer static constrained TypeVar solutions (#27057)
• Preserve frozen-dataclass setter delegation (#27217)
• Preserve inference when filtering constructor overloads (#27254)
• Reject frozen-dataclass field deletion through subclasses (#27001)
• Stabilize recursive type-constraint ordering (#27176)
• Support materialized class type expressions (#27258)

Performance

• Avoid quadratic inference for large literal unions (#27178)
• Cache protocol receiver binding (#27301)

Contributors

• @thejchap
• @benedikt-bartscher
• @carljm
• @charliermarsh

Install ty 0.0.65

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.65/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.65/ty-installer.ps1 | iex"

Download ty 0.0.65

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-07-27.

Bug fixes

• Fix identity narrowing for NewTypes (#26439)
• Make reachability analysis idempotent (#27163)

LSP server

• Fix ParamSpec declaration hover and type navigation (#27183)
• Implement LSP textDocument/implementation request (#25410)
• Introduce shared primitives for parsing backticks in docstrings (#26928)
• Render NumPy docstrings as structured Markdown (#25925)

CLI

• Add --exclude-scripts and --include-scripts (#27169)
• Discover uv workspace roots (#25551)

Diagnostics

• Add a lint rule for combined abstract and final decorators (#26932)
• Change --add-ignore to add space after the colon for ty: ignore (#27120)
• Fix missing-override-decorator suggestion before Python 3.12 (#27166)
• Reuse full call diagnostics for implicit setter calls (#27115)

Configuration

• Allow unresolved unused venv home paths (#27162)
• Simplify script metadata query (#27121)

Core type checking

• Decorate only overload implementation signatures (#27147)
• Don't consider known-instance types, generic aliases or non-singleton special-form types to be single-valued (#27137)
• Improve identity comparison inference for singleton types (#27126)
• Improve tuple membership and rich comparison inference (#27164)
• Model walrus bindings from comprehensions (#26466)
• Narrow tagged unions using identity comparisons (#27130)
• Preserve Self in __new__ calls (#27003)
• Preserve receiver constraints when binding overloaded methods (#27038)
• Support generic manual PEP 695 type aliases (#27083)
• Treat bivariance as covariant (#24319)

Performance

• Avoid cycles when resolving ModuleType globals (#27182)
• Avoid expanding optional enum comparisons (#27105)
• Avoid repeated inference when copying mixed TypedDict unions (#27108)
• Improve importer performance (#27159)
• Improve union and intersection builder performance (#27167)

Contributors

• @perfloop-agent
• @carljm
• @lerebear
• @Gankra
• @TrapsterDK
• @MichaReiser
• @thejchap
• @mtshiba
• @denyszhak
• @charliermarsh
• @AlexWaygood

Install ty 0.0.64

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.64/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.64/ty-installer.ps1 | iex"

Download ty 0.0.64

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-07-23.

Core type checking

• Handle generic stringified PEP 613 (typing.TypeAlias) type aliases (#27092)
• Allow equality narrowing across non-final classes (#27031)
• Allow interpolated string literals to be promoted to str (#27104)
• Fix double specialization of generic type aliases (#27058)
• Fix intersections of type and TypeForm (#27099)
• When narrowing from a match statement leads a variable x to be inferred as A & B, infer the type of x.attr as <type of A.attr> & <type of B.attr> (#27103)

Library support

• Pydantic: Stricter validation of sub-model fields in lax mode (#27091)
• Pydantic: Support special underscore parameters in BaseSettings models (#27098)

Performance

• Avoid exponential narrowing of optional dynamic match subjects (#27100)
• Avoid normalizing cached absolute file paths (#26998)

Contributors

• @sharkdp
• @charliermarsh
• @ibraheemdev
• @carljm

Install ty 0.0.63

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.63/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.63/ty-installer.ps1 | iex"

Download ty 0.0.63

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-07-21.

Bug fixes

• Guard recursive Protocol and TypedDict relations (#26990)
• Prevent stack overflows in recursive type relation checks (#26503)
• Recover from cancelled file indexing (#26876)

Diagnostics

• Avoid editing ignore comments with trailing reasons (#26939)
• Prefer innermost inline suppressions (#26940)
• Remove unused own-line ignore comments (#27013)
• Reuse applicable own-line suppressions in --add-ignore (#26925)

Configuration

• Respect rules and analysis in PEP 723 script metadata configurations (#26671)

Core type checking

• Accept gradual constrained TypeVar solutions (#26965)
• Avoid recursive TypeVarTuple alias expansion (#27032)
• Check inherited method conflicts via the MRO (#27019)
• Contextually infer custom __setattr__ assignments (#27015)
• Fix Callable isinstance reachability (#26970)
• Fix Just[float] protocol matching (#27053)
• Fix Self binding for classmethod __new__ constructors (#27030)
• Fix nested short-circuit flow snapshots (#26956)
• Gate TypedDict PEP 728 parameters by Python version (#26968)
• Improve match reachability inference around value-pattern branches (#26979)
• Make membership and equality narrowing consistent (#26982)
• Preserve constrained TypeVar equality narrowing (#26988)
• Preserve constrained TypeVar inequality narrowing (#26995)
• Preserve unsatisfiable generic call constraints (#26964)
• Respect bounded typevars in union inference (#27023)
• Respect metaclass __setattr__ for class attributes (#27000)

Performance

• Cache non-terminal-call reachability prefixes (#26810)
• Cache protocol Self binding (#26997)
• Cache sparse reachability checkpoints (#26811)
• Defer statement-call narrowing gates (#26793)

Contributors

• @charliermarsh
• @MichaReiser
• @carljm
• @AlexWaygood
• @mtshiba

Install ty 0.0.62

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.62/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.62/ty-installer.ps1 | iex"

Download ty 0.0.62

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-07-17.

Bug fixes

• Avoid recursive protocol structural comparisons (#26721)

LSP server

• Render Google docstrings as structured Markdown (#26599)

Library support

• Pydantic: Collect field metadata through subscripted generic Annotated aliases (#26885)

Diagnostics

• Avoid extending own-line suppressions in --add-ignore (#26808)

Core type checking

• Derive descriptor setter domains for protocols (#26683)
• Enforce declared receiver TypeVar domains (#26863)
• Infer isinstance results for aliases and type variables (#26961)
• Infer isinstance results for fixed class tuples (#26935)
• Narrow inline list and set membership checks (#26955)
• Narrow tagged unions by tag truthiness (#26887)
• Narrow walrus expression values (#26949)
• Project intersections in to_instance (#26892)
• Remove inferable TypeVar artifacts recursively (#26787)
• Respect mixin receiver domains in method overrides (#26941)
• Support TypeVarTuple and Unpack (#25240)

Performance

• Deduplicate completion labels (#26890)
• Only collect expected types for files open in the editor (#25546)
• Parallelize subtype hierarchy search (#26875)
• Share heap-backed parser names with CharStr (#26594)
• Use the new incremental checker from the ignore crate (#26933)

Contributors

• @MichaReiser
• @denyszhak
• @lerebear
• @dhruvmanila
• @charliermarsh
• @BurntSushi
• @Aethryl
• @carljm
• @ibraheemdev

Install ty 0.0.61

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.61/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.61/ty-installer.ps1 | iex"

Download ty 0.0.61

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-07-15.

Bug fixes

• Expand transparent callable workaround with overloads and Awaitable[T] (#26761)
• Separate type-mapping caches by transformation mode (#26857)
• Avoid recursive protocol union redundancy checks (#26689)
• Handle recursive protocols in redundant-cast checks (#26708)

LSP server

• Prevent type that is written with a code span from being incorrectly re-wrapped during docstring Markdown rendering (#26723)

Library support

• Pydantic: Support populate_by_name and custom initializers (#26764)
• Pydantic: Warn about immediately discarded extra arguments (#26762)

Diagnostics

• Narrow TypeGuard keyword arguments and remove invalid-type-guard-call (#26809)
• Support own-line suppression comments (#26785)

Core type checking

• Derive descriptor setter domains for protocols (#26683)
• Handle cycles in derived constraint relations (#26814)
• Implement unified generic call inference (#26141)
• Preserve constraints from bound receivers (#26776)
• Project exact-length narrowing through TypeVars (#26852)
• Resolve PEP 695 aliases in type[...] annotations (#26842)
• Retain sequence pattern narrowing in successful match cases (#26807)
• Support class and static protocol methods (#26574)
• Support class objects satisfying instance-method protocols (#26789)
• Support type[Protocol] (#26649)
• Sync vendored typeshed stubs (#26840). Typeshed diff
• Treat transparent callable decorators consistently in class assignments (#26720)

Performance

• Compare overloaded protocol method returns pairwise (#26684)
• Extend PathBounds fast-path to support both upper and lower bounds (#26782)
• Skip Self type scans for non-generic instances (#26703)

Contributors

• @sharkdp
• @mtshiba
• @dhruvmanila
• @lerebear
• @carljm
• @charliermarsh
• @ibraheemdev
• @RasmusNygren

Install ty 0.0.60

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.60/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.60/ty-installer.ps1 | iex"

Download ty 0.0.60

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-07-12.

Bug fixes

• Guard descriptor classification cycles (#26690)
• Respect init=False in dataclass field-order checks (#26749)
• Avoid duplicate diagnostics for overloaded TypeIs (#26716)

Library support

• Pydantic: Support custom __init__ methods (#26699)
• Pydantic: Support field metadata in Annotated (#26650)

Core type checking

• Allow unsound equality-based narrowing for builtins (#26414)
• Bind Self in implicit dunder calls (#26711)
• Correct protocol method receiver binding (#26701)
• Exempt ParamSpec callables from the dunder descriptor heuristic (#26696)
• Remove transitive TypeVar artifacts during collection inference (#26714)

LSP server

• Avoid broad invalidation from file check eligibility (#26741)
• Correct how we expand tabs in docstrings (#26679)
• Resolve ambiguity in Google-style docstring parsing in favour of observations from popular projects (#26673)

CLI

• Avoid allocation for every stdout write (#26698)
• Buffer diagnostic output (#26702)

Performance

• Cache generic context (#26745)
• Cache known class instances (#26746)
• Reuse common TypedDict constraints through intersections (#26747)
• Use purpose-specific types for completion and module text (#26664)

Contributors

• @carljm
• @MichaReiser
• @charliermarsh
• @lerebear
• @ibraheemdev
• @sharkdp

Install ty 0.0.59

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.59/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.59/ty-installer.ps1 | iex"

Download ty 0.0.59

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-07-09.

Bug fixes

• Fix protocol matching for class variables (#26669)
• Fix reflected binary dispatch for runtime classes (#26623)
• Support cached properties in protocols (#26681)

Diagnostics

• Add assignability context to upper-bound diagnostics (#26645)
• Add blanket ignore comment rule (#26426)
• Improve protocol attribute diagnostic context (#26644)

Library support

• Pydantic: Add fields from mixin classes (#26631)
• Pydantic: Add support for validate_by_{name,alias} (#26598)
• Pydantic: Add support for validation_alias (#26629)
• Pydantic: Fix float conversion in unions (#26655)
• Pydantic: Ignore private attributes (#26630)
• Pydantic: Make BaseSettings fields optional by default (#26628)
• Pydantic: Recognize frozen models via config (#26648)
• Pydantic: Support dict model configurations (#26632)
• Pydantic: Support validation of RootModel fields (#26634)
• Pydantic: Understand ellipsis as providing no default value (#26637)

Core type checking

• Gate membership narrowing on __contains__ semantics (#25964)
• Handle callable classes in solver (#26090)
• Infer ModuleType.__doc__ as str in the presence of a docstring (#26505)
• Infer metaclass-declared attributes on class instances (#26512)
• Respect user stub overlays during module resolution (#26123)

Performance

• Avoid allocating decorated parameter names (#26666)
• Optimize TypeCollector (#26593)

Contributors

• @carljm
• @charliermarsh
• @mtshiba
• @MichaReiser
• @sharkdp
• @kaapstorm

Install ty 0.0.58

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.58/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.58/ty-installer.ps1 | iex"

Download ty 0.0.58

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-07-07.

Bug fixes

• Detect async generator expressions containing await (#26568)
• Preserve exhaustive gradual match patterns (#26523)

LSP server

• Fix selection range behavior for strings (#26532)
• Recognize that dedent ends doctest block when parsing docstrings for signature help (#26552)
• Render reStructuredText hyperlinks as Markdown in hover docstrings (#25907)
• Update __slots__ string when renaming an attribute (#26438)

Documentation

• Document PYTHONPATH support in module discovery (#3889)

Library support

• Add support for extra arguments in Pydantic model constructors (#26520)
• Detect Pydantic model configurations (#26573)
• Distinguish lax and strict mode for Pydantic models (#26587)

Core type checking

• Fix subtyping/assignability for @property protocol members (#25332)
• Narrow isinstance against intersections containing invalid member (#26545)
• Narrow match subjects through structural patterns (#25942)
• Preserve generic functools.partial signatures (#24583)
• Preserve generic variadic callback semantics (#26521)
• Preserve invariant materialization on generic specializations (#26578)
• Preserve literal enum member names (#26592)

Performance

• Avoid exponential invariant constraint paths (#26538)
• Batch parallel jobs when finding references (#26534)
• Build module names directly in CompactString (#26546)
• Elide default use-def state (#26398)
• Reuse owned buffers for string literals (#26547)
• Use ICF for macOS release builds (#3709)
• Use cached class literal lookup for is_subclass_of (#26585)

Contributors

• @sharkdp
• @fenghourun
• @zaniebot
• @charliermarsh
• @MichaReiser
• @shaanmajid
• @jvdillon
• @sqqueak
• @SuryanshSS1011
• @carljm
• @lerebear

Install ty 0.0.57

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.57/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.57/ty-installer.ps1 | iex"

Download ty 0.0.57

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-07-01.

Bug fixes

• Avoid MRO cycle when collecting NamedTuple fields (#26464)
• Model int and str enum value normalization (#26349)
• Prefer reflected operators by runtime class (#26434, #26474)

CLI

• Exit with status 130 when interrupted (#26465)

Performance

• Avoid exponential OR-pattern reachability (#26481)
• Reduce bound typevar identity overhead (#26396)

Core type checking

• Infer generic class pattern capture types (#26479)
• Narrow exact tuples through sequence patterns (#26424)
• Recognize inherited enum member constructors (#26410)
• Respect return-context inference when filtering overloads (#26454)
• Sync vendored typeshed stubs (#26501). Typeshed diff

Contributors

• @charliermarsh
• @sharkdp

Install ty 0.0.56

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.56/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.56/ty-installer.ps1 | iex"

Download ty 0.0.56

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-06-26.

LSP server

• Render full diagnostics in color (#26384)

Documentation

• Document colored diagnostic output (#3858)

Performance

• Improve vendored filesystem concurrency (#26408)
• Optimize enum comparisons in equality evaluation (#26340)
• Remove redundant semantic index shrinks (#26392)
• Use never-change durability for one-shot checks (#26359)

Core type checking

• Correct enum alias detection and scalar constructors (#26345)
• Fix structural pattern binding inference (#26411)
• Improve variable-length tuple slicing (#26151)
• Infer class and mapping pattern bindings (#25941)
• Infer empty collection constructors from later uses (#26389)
• Skip shadowed submodule bindings during import analysis (#26385)
• Sync vendored typeshed stubs (#26406). Typeshed diff
• Track literal iterable emptiness for reachability (#25222)
• Validate positional class patterns against __match_args__ (#26195)

Contributors

• @charliermarsh
• @carljm
• @AlexWaygood
• @MichaReiser
• @mtshiba
• @felixscherz

Install ty 0.0.55

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.55/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.55/ty-installer.ps1 | iex"

Download ty 0.0.55

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-06-25.

Bug fixes

• Avoid duplicate configuration error output (#26375)
• Avoid stack overflows in reachability analysis (#26272)
• Fix divergent recursive tuple cycle handling in ty (#26316)
• Fix panic from relation queries during cycle recovery (#26335)
• Fix panics by reverting recursive TypeOf cycle recovery (#26339)
• Support basic usages of __class__ closure cells in methods (#26329)

LSP server

• Fix typealias token classification inconsistency (#26255)
• Implement rust-analyzer's "Click for full compiler diagnostic" feature (#26269)

Performance

• Co-locate retained definition usage state (#26019)
• Use never-change durability for immutable file inputs (#26353)

Diagnostics

• Reject undeclared protocol instance attributes (#26336)

Core type checking

• Allow replacing ordinary methods with compatible functions (#26158)
• Distinguish typing.TypedDict from typing_extensions.TypedDict (#25843)
• Don't treat non-empty ranges as single-valued (#26351)
• Handle TypeVar bounds over type[...] in attribute lookup (#26146)
• Infer definite equality comparison results (#26337)
• Infer mismatched literal comparisons (#26313)
• match statements: make class-pattern fallthrough member-aware (#26283)
• match statements: prove TypedDict structural patterns exhaustive (#26285)
• match statements: resolve positional class-pattern exhaustiveness (#26284)
• Model non-exhaustive enum member sets (enum.Flags) (#26277)
• Reduce retained definition map storage (#26348)
• Reuse equality semantics for membership compatibility (#25955)
• Sync vendored typeshed stubs to support builtins.sentinel (#26341)
• Treat non-empty range calls as non-empty for reachability (#25220)
• Use assignability for divergent constraints (#26334)
• Widen inferred class-valued instance attributes (#26338)

Contributors

• @carljm
• @sqqueak
• @AlexWaygood
• @mtshiba
• @charliermarsh
• @MichaReiser

Install ty 0.0.54

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.54/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.54/ty-installer.ps1 | iex"

Download ty 0.0.54

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>

Release Notes

Released on 2026-06-23.

Bug fixes

• Avoid bypassing lazy constraints for Divergent (#26288)
• Avoid recursion when projecting narrowing constraints (#26276)
• Fix ParamSpec callable signature extraction for callable instances (#26279)
• Make multi-arm TypeOf cycle recovery monotonic (#26275)

LSP server

• Document all special forms in ty_extensions (#26263)

Performance

• Avoid cloning fallback condition flow snapshots (#26203)
• Avoid constructing discarded speculative diagnostics (#26251)
• Avoid path lookups when sorting same-file diagnostics (#26257)
• Cache is_never_satisfied results (#26261)
• Defer applying type context to simple standalone expressions (#26252)

Core type checking

• Infer types for names bound in match patterns (#25940)
• Preserve regular kind for callable instances (#26253)
• Simplify intersections of invariant generic types with Any specializations (#26127)

Contributors

• @charliermarsh
• @MichaReiser
• @AlexWaygood
• @sharkdp
• @ibraheemdev
• @carljm

Install ty 0.0.53

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.53/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.53/ty-installer.ps1 | iex"

Download ty 0.0.53

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ty

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>