ty 0.0.50

on Python PyPI

Release Notes

Released on 2026-06-17.

Bug fixes

• Avoid cross-TypeVar leakage in generic inference (#26099)
• Fix panic from oscillating collection-use constraints (#26031)
• Preserve type variables in fixed tuple aliases (#26041)
• Respect ParamSpec binding contexts (#25993)
• Show bare Final as a special form on hover (#26029)
• Support options in functional dataclass calls (#25989)

LSP server

• Add context-sensitive keyword completions (#26036)
• Fix wildcard import symbol range (#25740)
• Highlight decorated methods consistently (#26003)
• Preserve narrowing after qualified TYPE_CHECKING (#26051)
• Respect client's content format preference (#25957)
• Retain all diagnostic annotations in the server (#26006)
• Track unused-binding captures across nested scopes (#25536)

Diagnostics

• Fix override diagnostics for decorated methods (#25671)
• Improve duplicate-base diagnostics (#26107)
• Reject invalid dataclass flag combinations (#25985)
• Reject legacy TypeVars in PEP 695 class bases (#25975)
• Reject legacy TypeVars in PEP 695 functions (#25979)
• Respect @no_type_check in function validation (#25994)

Performance

• Avoid rebuilding unchanged specializations (#25826)
• Avoid redundant equality intersections (#26057)
• Avoid retaining empty use-def tables (#26018)
• Compact retained definition inference extras (#25838)
• Deduplicate retained scope inference types (#25846)
• Disable LRU tracking for one-shot checks (#26106)
• Fast path collection literals with exact type contexts (#25878)
• Flatten retained declaration states (#25912)
• Improve flow snapshot performance (#26012)
• Skip stub package checks in stub-free search paths (#25963)
• Speed up large-union narrowing (#26048)
• Speed up module resolution for projects with many search paths (#25962)
• Store cumulative binding end offsets (#25913)
• Use compact frozen representation for narrowing constraints (#25990)

Core type checking

• Annotate intersection and negation types using & and ~ (#26035)
• Diagnose zero-step slices on lists (#25966)
• Full-scope bidirectional inference for non-empty collection literals (#25280)
• Improve equality-based narrowing for ==, !=, and match (#25788)
• Infer precise values for standard-library enums (#26103)
• Make equality evaluation cycle-aware (#26055)
• Narrow equality across IntEnum classes (#26079)
• Narrow tuple expression match subjects (#25874)
• Preserve literal types for loop variables over literal collections (#25083)
• Preserve negative narrowing for starred sequence patterns (#25927)
• Preserve non-final types in Hashable unions (#26039)
• Support enum literals as tagged-union discriminants (#25855)
• Sync vendored typeshed stubs (#25952). Typeshed diff
• Sync vendored typeshed stubs (#25997). Typeshed diff
• Synthesize NamedTuple __match_args__ (#25934)
• Treat assigned enum hooks conservatively (#25958)
• Validate deprecated warning categories (#26025)

Contributors

• @AlexWaygood
• @MichaReiser
• @ankddev
• @sqqueak
• @lerebear
• @sharkdp
• @denyszhak
• @ibraheemdev
• @charliermarsh

Install ty 0.0.50

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ty/releases/download/0.0.50/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ty/releases/download/0.0.50/ty-installer.ps1 | iex"

Download ty 0.0.50

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>