Internals

Maintainer notes. Not user documentation — these record decisions, dead ends and measurements, and they assume you already know the codebase.

Design notes

value-semantics-limits.md — where the memory model costs, and why those costs were accepted.
design-aggregate-ref.md — aggregate references.
design-aggregates.md — how arrays and structs behave under value semantics with implicit arenas, and why no borrow checker is needed.
design-maps.md — map values and in-place mutation.
design-generics.md — generics monomorphization.
design-concurrency.md — concurrency runtime, channel core, and measurement.
design-ffi.md — FFI ownership, prototypes, and coverage.
design-corelib.md — corelib handle guards, path layering, and shim conventions.
design-gfx.md — core:gfx's values-and-handles-only boundary, ownership and thread rules.
design-subscripts.md — subscript lowering and rules.
design-enums.md — enum payloads and error operators.
design-functions.md — closure capture and sink adoption.
design-scalar-match.md — scalar patterns in match.
goose-review.md — which Goose design ideas transfer to Tycho, with the incompatible ones named.

1.0-readiness.md — the 2026-11-10 readiness snapshot: internal gates, current performance, and the two external requirements.
archived-c-compiler.md — the deleted C compiler, the revision its citations resolve against, and the frozen reject-site index.
FRICTION.md — the running log of what fought back while writing real programs against this language. The primary source for what is actually hard here.
audit-brief.md — what a third-party reviewer would need.
cold-probe-binary-2026-10-26.md — a docs-only binary-protocol server/client probe, its friction and the doc or corelib fixes it produced.
ffi-review-2026-08-14.md — an FFI boundary review.
audit-2026-08-16.md — security audit across the whole threat model: two vulnerabilities found and fixed, and what it did not cover.
audit-2026-09-25.md — a defect hunt across the compilers, runtime, shims, network stack, tycho-db and parsers: 90 baseline defects recorded, all 90 fixed, none open.
roadmap-closed-2026-08.md — the 1.0 conditions closed in August 2026, moved out of ROADMAP.md.
windows-port.md — the design record of the native Windows port. Cited by tests/run.sh, scripts/ci.sh and the wine lanes.

corelib-parity.md — Odin core capability map, the explicit non-goals, and the staged order for closing the gaps.
plan-value-storage-places.md — storage reuse, the inout append fix, and follow-up evidence/documentation corrections.

Each plan-*-DONE.md is the finished record of one campaign, kept for its evidence rather than its instructions: repo-polish, chess, kv, kvsrv, rsa, sat, scheme, scheme-compiler, vm.