v0.19.0

0.19.0 (2026-09-06)

⚠ BREAKING CHANGES

• constraints: String.Min / Max count Unicode characters, not UTF-8 bytes. Use MinBytes / MaxBytes when you need a byte-size limit.
• diagnostics: consumers of Diagnostic.Msg, diagnosticf, or legacy diag message formatters must use Report fields / FormatReport and pass spans at every user-facing emit site.
• refinements: ensure … or Err(...) as the failure form is replaced by ensure … else Err(...). Migrate existing failure sites to else; reserve or for assertion alternatives such as A() or B().
• Ensure failure blocks now require the else keyword. Bare failure blocks without else will produce a parse error.

Features

• constraints: expand built-in string and number checks (#203) (0556c4d)
• diagnostics: ship structured reports with real spans (#201) (8f51c42)
• lsp: complete exported names after Go pkg. (c364b92)
• refinements: ensure proofs that survive until mutation (#198) (a6aac0f)
• testrunner: run native Go-only _test.go packages (c364b92)
• typechecker: allow ensure against named constrained types (#204) (d84233f)

Bug Fixes

• compiler: link sibling Go sources in forst run sandboxes (#199) (c364b92)
• transformer: register bridge return types via RegisterTypeIfMissing (8bcafcb)
• vscode: highlight ensure else ErrorName sites (a6aac0f)

Performance Improvements

• hasher: cheap HashNode identity and little-endian writes (#202) (b671eb3)

Documentation

• document implicit Error propagation for ensure !err (a6aac0f)