Kit Updated: 2026.6.11

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Kit 2026.6.11 is a busy release centered on applications, parser ergonomics, and capability tooling. Plain projects now get first-class application manifests with project-local installs, lambdas can trail a call as the final argument, interpolated heredocs dedent correctly, and capability errors are aggregated into a single actionable report backed by a new trust-on-first-use consent store. Cold builds also get noticeably faster.

What Changed

Applications are now first-class: a plain kit init creates an application kit.toml (not publishable), dependencies install project-locally to ./kit-packages/, and a bare kit run executes the manifest entry-point, much like cargo run. kit add in a directory without a manifest now offers to create one. Packages can also declare a kit-version compatibility pin that kit install enforces.

Capability errors get a major usability pass: instead of reporting missing package capabilities one at a time, the compiler now aggregates them into a single C004 diagnostic listing every missing capability along with the complete --allow command. A new --allow-requested flag grants exactly what packages declare, and a trust-on-first-use consent store remembers capability grants so you only approve them once.

The parser learns two documented-but-missing ergonomics: trailing lambda arguments (f arg fn(x) => body parses as the final call argument) and multi-line parenthesized lambda blocks. Interpolated squiggly heredocs now strip common indentation and drop the trailing newline, matching plain heredocs. Three more documented-but-unimplemented parser gaps surfaced by the website guides are fixed, so the tour and grammar examples now compile as written.

Thanks to Alvydas ( avitkauskas) for reporting and helping test the interpolated heredoc indentation issue (#201) and the documentation example parser gaps (kit-website #4, #5, #6) behind these fixes.

Build performance improves across the board: the full stdlib tree is embedded at build time (standalone binary installs now ship the complete stdlib), backend compile phases overlap, and partition codegen resolution paths are memoized for faster cold builds. The compile spinner is suppressed when stderr is not a TTY, keeping CI logs clean.

Quality work rounds out the release: generated-program differential backend testing, property-style tests for List builtins, executable docs and formatter properties, codegen fixes for capability capture discards and inlined constant operands, parser memory leak fixes in sql blocks and using expressions, quasiquote formatter spacing, and a wasm build fix that keeps Io.Threaded out of freestanding targets.

Release Highlights

• Add application manifests with project-local installs; bare kit run uses the manifest entry-point.
• Support trailing lambda arguments and paren-closed lambda blocks.
• Strip common indentation across interpolated heredoc segments.
• Aggregate capability errors into one C004, add --allow-requested, and add a trust-on-first-use capability consent store.
• Add kit-version compatibility pinning for packages.
• Embed the full stdlib tree and speed up cold builds.
• Add differential backend testing and property-style List tests.

Release Commits

The list below uses the v2026.6.9..v2026.6.11 tag range, with each short SHA linked to the corresponding GitLab commit in kit-lang.

• Fix capability capture discard codegen regression (40b600e)
• Memoize partition codegen resolution paths for faster cold builds (4b52499)
• Overlap backend compile phases and trim cold-build overheads (8ee4e22)
• Bypass zig command cache in tests (c7f00ce)
• Embed the full stdlib tree, generated at build time (810d155)
• Add application manifests with project-local installs (44dd554)
• Report all missing package capabilities in one C004 (00dd0a3)
• Support trailing lambda arguments and paren-closed lambda blocks (d782ac7)
• Strip common indentation across interpolated heredoc segments (fbc7405)
• Fix three documented-but-unimplemented parser gaps (3ed5411)
• Add executable docs, formatter properties, and repair the fuzz step (a8159fa)
• Add generated-program differential backend testing (fb9710f)
• Inline skipped local constants in unboxed arithmetic operands (7d1dfed)
• Add property-style tests for List builtins (6924150)
• Fix parser memory leaks in sql blocks and using expressions (f8d2c49)
• Preserve spacing before unquote tokens in quasiquote bodies (c545d43)
• Suppress the compile spinner when stderr is not a TTY (fc97f21)
• Run the manifest entry-point when kit run gets no file (e0ae919)
• Add kit-version compatibility pinning for packages (116d90d)
• Aggregate capability errors across packages; add --allow-requested (2a1f727)
• Bump version to 2026.6.11 and regenerate changelog (7b2bdc2)
• Fix wasm build: keep Io.Threaded out of freestanding targets (0bfe045)
• Regenerate changelog (c242a3b)
• Add trust-on-first-use capability consent store (c84d450)