Sailfin Enhancement Proposals

SFEP Purpose and Process

Capsule Distribution and the Registry Protocol

The Toolchain Surface and Its Output Contracts

sfn check — Fast Analysis Without Codegen

Colon Type Annotations

Unified Build Architecture

sfn fmt — Canonical Formatter

Effect Validation as Build Gate

CLI Modularization

Tracks #351

Sailfin-Native Test Infrastructure

Tracks #965, #839, #842, #840 (historical intake); SFN-17

Content-Addressed Test Artifacts and Deterministic Suite Partitioning

Tracks #1012, #1230, #1233, #843 (historical intake); SFN-431, SFN-545, SFN-547

Result<T, E> and the ? Operator

Tracks #321, #323

Host-Aware exe_path Intrinsic

Agent-Legible Build/Test Output

Tracks SFN-725, SFN-726

The Capability-Sealed Runtime — Claim Ladder and Link-Time Admission

Hierarchical Sub-Effects as Subsumption

Tracks #1180, #1182

Borrow / Ownership Checking for the Native Runtime

Tracks #1207, #1209

sfn/http — Typed HTTP Surface

Tracks #1321

Role-Oriented Compiler Capsules

Tracks #345 (historical epic); Linear project Role-Oriented Compiler Capsules. §3.7 steps 1-2 (landed): SFN-705, SFN-706, SFN-707, SFN-708, SFN-709, SFN-710, SFN-711, SFN-712, SFN-713, SFN-714, SFN-715, SFN-717, SFN-718, SFN-734. §3.7 steps 3-8 (groomed 2026-08-06): SFN-735 through SFN-751. §3.3.1 remediation: SFN-894.

Native Windows Self-Host (MSVC ABI)

Tracks SFN-53, SFN-54, SFN-55, SFN-56, SFN-57, SFN-58

Darwin (macOS arm64) Memory Governor

Tracks SFN-626

Capsule-Defined Decorators

Tracks #1557

Model Engines, Adapters, Tensors, Training

Native Runtime Architecture

Tracks #321, #322, #451, #822, #1089, #1118, #1181, #1203, #1209, SFN-558

Delivery Process — Drift-Tolerant Issues, Seed Discovery, Release Cadence

CLI Modularization — Per-Worker RSS Relief First, Then Migration

Tracks #1671

Typed / Generic-Element Array Higher-Order Functions (map / filter / reduce)

Tracks #1943, #1945

Lambda expression syntax for 1.0 — keep, reform, or defer

Tracks #690, #1683 (historical intake)

First-Class Function Values

Tracks #1609, #1610, #1172

Inline `export <declaration>` syntax

Tracks #1681, #1680

Infer untyped lambda parameter and return types from the expected call-site function type

Tracks #1683 (historical intake)

Length-aware ({i8*, i64}) ABI for query-side string runtime helpers

Tracks #1704 (historical intake)

Structured, Enforced `x is T` Type-Guard Operator

Tracks #1753

Deriving prelude-mirror registry signatures from the prelude (kill latent ABI drift)

Tracks #572, #1779, #1780

TLS termination + upstream TLS for the native runtime (OpenSSL)

Tracks #1540, #1820, #1821, #1822

Peer-Language Process Adoption — Merge Queue, ICE Discipline, Perf History, Corpus Runs, Reduction, Fuzzing

Tracks #1806, #1807, #1808, #1809 (Tier 1, §3.13)

Generic Type Parameter Constraints and Monomorphization

Tracks #1867, #1868, #1869, #1870, #1871, #1872

Nominal Object Model — Honest Rejection of TypeScript-Shaped Data Syntax

Tracks #1860, #1887, #1888, #1838, #1855, #1900, #1904, #1905

Global Artifact Cache Store and Garbage Collection

Tracks #1892, #1893

Unified expected-type + typing-environment context for the typecheck walk

Tracks #1900, #1904, #1905

Nested / Local Function Declarations (non-capturing static `fn` items)

Tracks #1609, #1922, #1935, #1940, #1950, SFN-108

Phase-scoped arena reclamation to reduce per-module peak RSS

Tracks #1989

Invocation-scoped runtime identity + in-process sha256 for the test runner

Tracks #1995, #1996, #1997, #1998, #1999, #2008, #2010

Shared-frontend test runner — parent compiles, children only execute

Tracks SFN-152, #2010, #1997

Native Toolchain Version Pinning + Dispatch

Tracks SFN-167, SFN-168, SFN-169, SFN-170, SFN-171, SFN-172

Compiler Bootstrap Manifest

Tracks SFN-197

Native crypto + TLS stack — removing the OpenSSL dependency

Tracks https://linear.app/sailfin/project/native-crypto-tls-stack-zero-openssl-5ce55ca8f46e

Effect-transparency for concurrency-primitive leaves (spawn / parallel / channel send·receive)

Tracks SFN-86, #1702

Streamed per-test results over a captured pipe (retiring the results.log/fail.bin side-channel)

Tracks SFN-393

Workspace Manifest — Multi-Capsule Policy and the Capability Envelope

Tracks SFN-413 (Phase 1 member declaration — multi-line arrays + glob, Done), SFN-412 (workspace.toml reflow after seed pin), SFN-414 (Phase 2 root [toolchain] default), SFN-415 (Phase 3 [workspace.package]/[workspace.dependencies] inheritance), SFN-416 (Phase 4a declared-surface capability audit), SFN-418 (Phase 4b inferred-surface audit), SFN-419 (Phase 4c sfn capabilities audit + enforce/warn gate), SFN-417 (Phase 5 default-members + exclude). Epic: Linear project 'Workspace Manifest & Multi-Capsule Policy'

Accelerated ML — Substrate Interop and Capability-Typed Accelerator Programming

Shape-Typed Tensor IR and Fusion

Tracks #2485, SFN-424, SFN-427, SFN-429

Low-Precision Numeric Substrate

Tracks #2484, SFN-423, SFN-426

Typed task handles (Task<T>) and ordered multi-await (join_all)

Tracks SFN-440, SFN-441, SFN-446

aarch64-Linux Target Support (Raspberry Pi Install + On-Device Self-Host)

Tracks SFN-471,SFN-472,SFN-473,SFN-474,SFN-475,SFN-476,SFN-579,SFN-580,SFN-581,SFN-644,SFN-798,SFN-799,SFN-826

String Interpolation with ${ } (migrating off {{ }})

Tracks SFN-482 (Phases 1–3), SFN-483 (Phase 4), SFN-576 (literal escape)

Sized Integer Types and Overflow Semantics

Tracks SFN-501, SFN-502, SFN-503, SFN-570, SFN-573

Typed SSA Activation — Making the Metadata IR Load-Bearing

Tracks SFN-508, SFN-509, SFN-511, SFN-512, SFN-514, SFN-517, SFN-519; structured types: SFN-585, SFN-588–SFN-606

The Owned Syscall Layer (Axis 3, tier-1 Linux x86-64)

Tracks SFN-510, SFN-513, SFN-515, SFN-516, SFN-518, SFN-520, SFN-521, SFN-522, SFN-523, SFN-524, SFN-525

Diagnostic Unification — One Coded, Spanned, Severity-Bearing Diagnostic

Tracks SFN-534, SFN-535, SFN-536, SFN-537, SFN-538, SFN-539, SFN-540, SFN-541, SFN-608, SFN-915, SFN-916

Numerical and Behavioural Contracts (the Result Pillar)

sfn/sync — scope and blocking predecessor for a synchronization capsule

Generic resource-reclamation seam

sfn/sync — public API surface and semantics

Codegen Provider Ownership — Which Toolchain Roles Sailfin Owns

Tracks https://linear.app/sailfin/project/cross-platform-clang-independence-baeafe4f0a9a

Platform Access Ownership — the `-nostdlib` Program

Native Cross-Target Builds (`sfn build --target=<triple>`)

Tracks SFN-774, SFN-775, SFN-776, SFN-777, SFN-1039, SFN-1117

Non-Elidable Zeroization for Uniquely Owned Secret Buffers

Tracks SFN-703, SFN-782, SFN-783, SFN-784, SFN-785, SFN-786, SFN-787, SFN-788, SFN-789, SFN-790, SFN-791

Import-Reachability Filtering of the Capsule Source Closure

Tracks SFN-804, SFN-830, SFN-831, SFN-832, SFN-833, SFN-834, SFN-894

In-Process .tar.gz Reader and Writer (sfn/archive)

Tracks SFN-753

Domain-Oriented Repository Topology

Tracks https://linear.app/sailfin/project/repository-topology-and-capsule-layout-fd4f474aaaae

Installed Toolchain Lifecycle, Exact Selection, and Update Policy

Tracks https://linear.app/sailfin/project/installed-toolchain-lifecycle-e6024b4498bb

Repo Tooling Ownership — Retiring `scripts/` into Native Verbs

Tracks https://linear.app/sailfin/project/repo-tooling-ownership-13d4826f99a9

Concurrency runtime maturity — cancel-on-fault and async I/O

Tracks #1540, #1963

Derivable Interface Implementations (@derive)

Compile-Time Match Exhaustiveness Checking

Generic Collections — Map, Set, and Tuple

Tracks #1941

Import-surface compaction across the phase rewind to cut emit peak RSS

Tracks SFN-382; supersedes SFN-94

Signature-Checked Interface Conformance

Shared runtime/dep object cache for nested builds in the e2e suite

Nullable Access Operators (?. and ??)

Cross-invocation runtime-object persistence for the `sfn test` link path

Tracks SFN-1086