Kit Updated: 2026.5.31 - Kit Programming Language

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This post covers Kit v2026.5.31. The detailed notes below come from the project changelog.

Kit 2026.5.31 is a focused compiler, type-checker, FFI, and tooling release. It keeps Unit-parameter callees and release-list temporaries alive, improves type annotation handling, adds a warning for unknown annotation type names, fixes an FFI extern-call panic, and tightens package wrapper linking for installed Kit packages.

The type checker now treats lowercase identifiers in type annotations as quantified type variables and warns with W021 when an annotation references an unknown type name. Release tooling also now asks whether to use a suffix or tomorrow's date when the computed version already matches today's date.

Release Snapshot

Release: v2026.5.31
Date: May 31, 2026
Changelog entries: 6
Primary areas: compiler lifetime fixes, type annotation inference, annotation warnings, FFI extern safety, ffi-zig package linking, release tooling

What Changed

The compiler keeps Unit-parameter callees and release-list temporaries alive, covering regressions tracked in issues #153 and #154.

Type annotations are more expressive and better checked. Lowercase annotation identifiers are treated as quantified type variables, and unknown type names now produce warning W021 instead of silently passing through.

Thanks to Greg ( prosumma) for reporting and helping test the release-build regression (#154) and the polymorphic annotation issue (#155) that these fixes address.

FFI calls are safer: passing a Float to an Int-typed extern-c parameter no longer panics, and ffi-zig wrapper linking resolves installed Kit package directories.

Version tooling is clearer when today's version is already in use: the bump script now prompts for a same-day suffix or tomorrow's date instead of choosing implicitly.

Release Highlights

Keep Unit-parameter callees and release-list temporaries alive.
Treat lowercase annotation identifiers as quantified type variables.
Warn with W021 on unknown type names in annotations.
Fix an FFI panic when a Float reaches an Int-typed extern-c parameter.
Resolve installed Kit package directories when linking ffi-zig wrappers.
Prompt for same-day suffix vs. tomorrow's date when bumping an already-current version.

Exact Changelog

The list below matches the 2026.5.31 changelog entry, with each short SHA linked to the corresponding GitLab commit in kit-lang.

fix(compiler): keep Unit-param callees and release list temporaries (#153, #154) (e772ed6)
fix(type-checker): treat lowercase annotation idents as quantified type variables (#155) (24cb7d2)
feat(type-checker): warn (W021) on unknown type names in annotations (#156) (c79d76a)
chore(tools): prompt for suffix vs tomorrow when version matches today (41958b2)
Fix FFI panic when a Float reaches an Int-typed extern-c parameter (3cb187e)
fix(ffi): resolve installed Kit package dirs when linking ffi-zig wrappers (f864562)
Bumped version to 2026.5.31 (18ae580)