ty 0.0.78

on Python PyPI

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>