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Mighty Spec Changelog

Chronological log of changes to the Mighty language specification. Each entry references the slice / release in which the change shipped and the originating amendment number (Axx) where applicable.

Status codes match the docs/spec/v0.1-amendments.md legend:

  • F = FROZEN (folded into v1.0-RC verbatim, stable v1.x)
  • S = SUPERSEDED (later amendment took over; see cross-reference)
  • O = OPEN (v1.0 ships as-is; v1.1+ may evolve)
  • R = REVERTED (none yet)

The consolidated normative spec is docs/spec/v1.0-rc.md. Reconciliation notes for contradictions resolved during consolidation are at SPEC_CONSOLIDATION_V0_8_NOTES.md.

v0.1 (slices 1..8) — initial spec ladder walk

The 39-section stardust_language_spec_v0_1.md was the seed document. Slices 1..8 implemented the ladder; the amendments below were adopted en route. No amendment is R — every decision either landed or got superseded by a later, better-shaped one.

Slice 2 (v0.1 surface — lexer/parser/CST)

Amendment Status Title
A1 F Decimal size-literal suffixes k and M
A2 F Expression-position turbofish Path::[T1, T2]
A3 F Keyword-tolerant .method and .field
A4 F Keyword-tolerant effect names
A5 F run <expr> as an expression form
A6 F if let Pattern = expr { ... }

Slice 3 (v0.1 surface — type checker)

Amendment Status Title
A7 F ? strictly requires Result-returning enclosing fn
A8 S → A19 Integer-literal defaulting to I32 (deferred)
A9 F Primitive type names in both namespaces
A10 S → A17 + A65 Built-in method table (residual permissive only)
A11 O Anonymous error unions T!{A,B} → Result[T, Error]
A12 F Postfix ?/! require Msg ident on same line

Slice 4 (v0.1 surface — borrow checker)

Amendment Status Title
A13 S → A26 Hardcoded Copy set (replaced by #[derive(Copy)])
A14 S → A65.b Conservative Sendable set
A15 O Arena escape: direct-naming MVP
A16 F Match exhaustiveness promoted to Error
A17 F Method dispatch policy (inherent first, then traits)
A18 S → A28 + A65.c Protocol-aware agent handler params (Warning)
A19 F Integer/float defaulting pass (closes A8)
A20 S → A55 Lexical borrow regions (Rust 2015 style)
A21 S → A65 Scope-aware tolerance for unresolved values

Slice 5 (v0.1 surface — effects + traits + sandboxes)

Amendment Status Title
A22 F Effect inference algorithm (bottom-up + fixpoint)
A23 F Capability narrowing constraints
A24 F Trait coherence (name-only) + dispatch
A25 F dyn Trait object safety
A26 F Derive set (Copy, Hash, Eq)
A27 S → A43 Top-level sandbox items (metadata-only at parse)
A28 F Strict protocol-handler checks (supersedes A18)
A29 S → A56 move *ref reserved as MT3009
A30 F Strict-profile alloc ban

Slice 6 (v0.1 surface — interpreter)

Amendment Status Title
A31 O Arena runtime enforcement deferred
A32 S → async dispatch Slice-6 agent dispatch is synchronous
A33 F Effect calls dispatched via Host trait
A34 S → A43 + A70 + A99 Budgets + sandboxes are metadata only
A35 F Slice-6 interpreter is single-thread deterministic

Slice 7 (v0.1 surface — runtime)

Amendment Status Title
A36 S → A96 std.http.serve MVP shape (in-memory)
A37 S → A50 + A99 Slice-7 memory budget approximation
A38 S → A71 Telemetry JSON schema (OTLP-flavoured)
A39 F Deterministic mode (RuntimeBuilder::deterministic)
A40 F Mailbox defaults (depth 1024, policy Block)
A41 S → A70 Slice-7 cancellation semantics (between-turn only)
A42 F restart up_to N in DUR semantics
A43 F Top-level sandbox executes as a child runtime
A44 F Slice-7 deref-of-ref write path
A45 O mty run --legacy-interp opt-out

Slice 8 (v0.1 surface — codegen)

Amendment Status Title
A46 F Cranelift-only native backend; LLVM scaffolded
A47 O Wasm Component Model deferred (core modules only)
A48 F mty run defaults to JIT (Cranelift)
A49 O Per-(fn, type-args) monomorphisation (strip in MVP)
A50 F bumpalo-backed arenas with byte-charging
A51 F Codegen trap codes MT8001..MT8010
A52 F Native linker discovery order
A53 F extern { fn ... } resolved via libloading

v0.3 — soundness pass

The first post-v0.1 release. Goal: harden the soundness of borrows, cancellation, telemetry, mailbox shape, and scope-strictness.

Amendment Status Title
A54 F Field-level borrow tracking via Place algebra
A55 F NLL last-use deactivation (supersedes A20)
A56 F Precise MT3009 for move *ref (supersedes A29)
A65 F Scope-aware permissive/strict type-check policy
A65.b F Sendable trait at cross-agent message sites
A65.c F MT4031 strict handler param-type check
A65.d F core profile rejects alloc (ratified)
A70 F Cooperative mid-turn cancellation (supersedes A41)
A71 F OTLP wire-format telemetry (supersedes A38)
A72 F Slab-pool mailbox frames
A73 F Batched per-turn deadline scheduler

Note on numbering: A57..A64 and A66..A69 are skipped (reserved slots used by intermediate drafts during v0.3 development that did not ship).

v0.4 — dogfood + ecosystem

Goal: stand up a real package manager, declarative macros, doc gen, and the registry surface.

No new spec amendments. Highlights:

  • mty-pkg package manager + mighty.lock resolution.
  • Declarative macros + hygienic mangling (precursor to A92).
  • mty doc HTML generator.
  • Registry index protocol shaped per §36.3.
  • mty new package scaffolder.

See RELEASE-v0.4.md and REGISTRY_V0_4_NOTES.md.

v0.5 — self-host lexer + dogfood completion + LSP advanced

Goal: prove self-hosting by porting the lexer, close v0.4 dogfood gaps, and expand the LSP capability surface.

LSP

Amendment Status Title
A74 F LSP v0.5 capability expansion (semantic tokens, rename, inlay hints, code actions, signature help, semantic completion)

Control flow

Amendment Status Title
A80 F break / continue as real HIR nodes
A81 F Iterator protocol via __sdust_iter_next
A82 F Loop back-edge fixed-point in the borrow checker

Macros

Amendment Status Title
A90 F name!(args) macro invocation marker
A91 F MT6001 unknown_macro activated
A92 F Extended hygiene mangling (tuple/struct/ref patterns)
A93 F Cross-file pub macro
A94 O Procedural macros (parse + store + purity check)
A95 F Standard macro library shipped with mty-macros

Dogfood gap closures

Amendment Status Title
A96 F std.http.serve binds a real socket (supersedes A36)
A97 O mighty:web/dom interface added (canonical-ABI bridge OPEN)
A98 F Str method table real impls
A99 F RunResult::MemBudgetExceeded + memory auto-charging
A100 F FsCap allowlist enforcement (process-wide default cap)

Note: A75..A79 and A83..A89 are skipped (reserved during v0.5 development; not used).

v0.6 — multi-core scheduler + benchmarks + self-host parser

Goal: distribute work across N cores, ship first honest benchmarks, and port the parser to Mighty.

Scheduler

Amendment Status Title
A101 F v0.6 multi-worker scheduler (N tokio + crossbeam-deque)
A102 O Agent affinity hints (runtime API only; syntax v1.1+)
A103 O Lightweight migration (routing-table; lossless v1.1+)
A104 F Per-worker scheduler telemetry
A105 F Scheduler driver runtime separation
A106 F Default worker count = available_parallelism()

Integrator easy wins

Amendment Status Title
A107 F Central diagnostic catalog for MT6001-MT6006
A108 F BuiltinId::DomOp(name) MtyIR variant (closes v0.5 deferral #6)
A109 F Per-call FsCap isolation contract

v0.7 — brand rename (Stardust → Mighty)

Tag: v0.7.0-rebrand. Commits: b83673a → 36b3140.

No new spec amendments. The rebrand consolidates four identifier sweeps:

Old New
Language name Stardust Mighty
CLI binary sdust mty
Source extension .sd .mty
Interface extension .sdi .mtyi (no files yet existed)
Manifest filename star.toml mighty.toml
Lockfile star.lock mighty.lock
IR name SIR MtyIR
Diagnostic prefix SDxxxx MTxxxx
Rowan language type Stardust Mighty
Profile dir .stardust/ .mighty/
Crate prefix sdust-* mty-*
WIT namespaces stardust:caps/*, stardust:web/* mty:caps/*, mty:web/*

GitHub repo URL was later renamed hassard0/stardust → hassard0/Mighty (the on-disk directory may still be stardust on some clones; both resolve to the same repo).

Preserved:

  • edition = "2026" (calendar year, not brand)
  • wasi:* WIT namespace (upstream WASI types)
  • STARDUST_* env var prefix (back-compat with v0.6 deployments)
  • pkg.stardust.dev registry URL constant (until a Mighty-branded registry comes online)

See REBRAND_NOTES.md and RENAME_LOG.md for the full interpretation log.

Back-compat shims:

  • mty explain accepts MT0001 (canonical) AND SD0001 (legacy).
  • mty dump --sir is a clap alias of mty dump --ir.
  • The .sd source extension still parses (deprecation review v1.2, removal v2.0 earliest).

v0.8 — spec consolidation (v1.0-RC)

This release. Goal: fold the 88 amendments into a normative v1.0 release candidate spec.

Outputs:

Classification totals:

Status Count
FROZEN 63
SUPERSEDED 15
OPEN 10
REVERTED 0
Total 88

No normative behaviour changed in v0.8. The consolidation is docs-only.

v1.0-RC2 (v0.9 spec-freeze prep, 2026-05-24)

The v0.8 consolidation classified 10 amendments as OPEN. v1.0-RC2 resolves each one — three reclassified to FREEZE-MVP (the MVP behaviour is the v1.0 normative contract; v1.1+ extensions land as additive amendments), seven retained as DEFER-V1.1 with explicit RFC tracking — and ships six first-draft RFCs covering the architecturally-significant v1.1+ promotion paths.

No normative behaviour changed in v0.9. The diff against RC1 is restricted to:

  • Per-amendment **Status:** updates in docs/spec/v0.1-amendments.md.
  • Spec title bump (v1.0-RC → v1.0-RC2) and §A.1 / §A.2 prose promotion in docs/spec/v1.0-rc.md.
  • New RFC directory docs/spec/rfcs/ with six RFCs.
  • New SPEC_FREEZE_V0_9_NOTES.md at repo root documenting the resolutions + v1.0 freeze plan + freeze blockers + post-v0.9 work.

OPEN-amendment resolutions

Amendment RC1 status RC2 resolution RFC
A11 OPEN DEFER-V1.1 RFC-001
A15 OPEN FREEZE-MVP —
A31 OPEN FREEZE-MVP —
A45 OPEN DEFER-V1.1 —
A47 OPEN DEFER-V1.1 RFC-002
A49 OPEN FREEZE-MVP —
A94 OPEN DEFER-V1.1 RFC-003
A97 OPEN DEFER-V1.1 RFC-002
A102 OPEN DEFER-V1.1 RFC-005
A103 OPEN DEFER-V1.1 RFC-006

A100 was FROZEN at RC1 (process-wide-default cap is the v1.0 normative contract) but carried a v1.1+ residual tag for MtyIR-lower per-call cap threading. RC2 adds RFC-004 to track that residual without reclassifying A100 itself.

RFCs drafted

RFC Covers Target Comment window
RFC-001 A11 first-class union ADTs v1.1 30 days
RFC-002 A47 + A97 Wasm Component Model wrapper v1.1 60 days
RFC-003 A94 sandboxed proc-macro execution v1.1 30 days
RFC-004 A100 carryover + A109 per-call FsCap v1.1 30 days
RFC-005 A102 agent affinity front-end syntax v1.1 14 days
RFC-006 A103 lossless live agent migration v1.1 or v1.2 60 days

Classification totals at RC2

Status Count
FROZEN 63
FREEZE-MVP 3 (A15, A31, A49)
SUPERSEDED 15
DEFER-V1.1 7 (A11, A45, A47, A94, A97, A102, A103)
REVERTED 0
Total 88

(FROZEN and FROZEN-MVP carry the same v1.x stability commitment. The "MVP" qualifier signals that a v1.1+ additive extension is planned; the MVP behaviour itself never changes.)

v1.0-RC3 (v0.12 spec polish, 2026-05-25)

The v0.11 Python 2nd implementation surfaced three normative gaps in the RC2 spec and sixteen interpretation ambiguities the impl had to guess at. v1.0-RC3 closes all three gaps and codifies a decision for every ambiguity. No normative behaviour changed in v0.12 — the Rust reference compiler already implements every decision here; RC3 just promotes those implementation choices into normative prose so a third or fourth front-end implementation can build to spec alone.

Gaps closed (originating: KNOWN_ISSUES #10 / #11 / #12)

Issue Topic RC3 resolution
#10 Operator precedence not normative New §11.1.1 promotes the Pratt precedence table from crates/mty-syntax/src/parser/exprs.rs verbatim. docs/internals/parser.md now points at the spec for the authoritative table.
#11 Six FROZEN typeck codes are constructor-only Per-code disposition in new §33.1: all six RETAINED as "FROZEN — emit-site landing in v1.x". Each describes a real future-emit condition; code-points + explain text are stable; the Rust compiler funnels them into more general codes today.
#12 package / export / requires + other lexer keywords missing from §3.3 §3.3 rewritten into §3.3.1 reserved keywords (full 63-word v1.0 list including the booleans), §3.3.2 contextual keywords (4 positions), §3.3.3 reserved for future use (7 names the spec reserves but the v1.0 lexer treats as identifiers). §4.1, §21.1, §26.2 add per-keyword syntax sections.

Python-impl ambiguities resolved (originating: PYTHON_IMPL_V0_11_NOTES.md)

All 16 findings have a normative disposition (full table in SPEC_RC3_V0_12_NOTES.md). Findings #6, #8, #9, #12, #16 are covered by the gap-closure work above. The remaining 11:

# Topic RC3 spec edit
1 Underscore-separator placement in INT_LITERAL §3.4.1 — MT0006 for leading / trailing / consecutive underscores.
2 5K lex behaviour (K reserved) §3.4.4 — unrecognised suffix letters lex as IDENT continuation; no lex-time diagnostic.
3 HTML literal interpolation layer §3.4.3 + §22.2 — body lexes as single HTML_LITERAL token; interpolation split is v1.0 OPEN, candidate A110.
4 Unterminated block-comment diagnostic §3.2 — MT0004 unterminated_block_comment.
5 /// vs //// §3.2 — exactly 3 slashes = doc comment; 4+ = ordinary line comment.
7 Postfix ?Msg same-line + trivia comments §3.5 / §11.1.1 footnote — newline in ANY trivia (whitespace or comments) forces bare-propagate interpretation.
10 Bare fn ... = <expr> body form §4.4 — promoted to normative shorthand.
11 Struct field separator (newline vs comma) §4.5 — both accepted; a single body may mix.
13 Sandbox / budget entry separator (= vs none) §16.2 — both shapes accepted; = recommended.
14 arena <label>: <expr> inline form §10.1 — promoted to normative alternative.
15 Anonymous protocol-message decl (Ping(...)) §13.1 — bare form and msg-prefixed form both accepted.

Diff summary (RC2 → RC3)

  • docs/spec/v1.0-rc.md: title bump RC2 → RC3; new §11.1.1 (operator precedence table); rewritten §3.3 (keyword set, +20 keywords); expanded §3.2 / §3.4 / §3.5 (lexer ambiguities closed); new §4.1 (package decl), §4.4 (= <expr> body form), §4.5 (field separators); expanded §10.1 (arena inline form); expanded §13.1 (bare msg form); expanded §16.2 (entry-separator forms); new §21.1 (requires clauses); new §26.2 (export <abi> fn); new §33.1 (FROZEN typeck codes deferred emit-site).
  • docs/spec/v0.1-amendments.md: status-legend section cross-refs RC3; candidate amendments A110 / A111 noted as deferred-to-v1.1+.
  • docs/internals/parser.md: precedence section now points at normative §11.1.1.
  • KNOWN_ISSUES.md: items #10, #11, #12 added to the catalog. #10 and #12 marked resolved in v1.0-RC3; #11 carries a per-code action table and remains open until each emit site lands.
  • dev/history/notes/SPEC_RC3_V0_12_NOTES.md: NEW — per-finding disposition rationale.

Candidate amendments tracked (not yet allocated)

  • A110 — HTML-literal interpolation lexing layer. Splits {name} placeholders from the HTML_LITERAL blob. Target v1.1.
  • A111 — Runtime / static enforcement of unsafe fn requires clauses. Target v1.x (likely after the broader verifier work).

Neither is allocated a number in docs/spec/v0.1-amendments.md until a v0.12+ slice ships the corresponding behaviour.

Classification totals at RC3 (unchanged from RC2)

Status Count
FROZEN 63
FREEZE-MVP 3 (A15, A31, A49)
SUPERSEDED 15
DEFER-V1.1 7 (A11, A45, A47, A94, A97, A102, A103)
REVERTED 0
Total 88

v1.0 (planned) — release stability

After the v1.0-RC3 bake-in period, v1.0 stable ships with:

  • The FROZEN + FROZEN-MVP matrix locked.
  • The DEFER-V1.1 matrix continues to evolve in v1.x minor releases per Appendix B.
  • The 6 RFCs enter their public comment windows; acceptance drives the v1.1 amendments.

Proposed v1.0 freeze date: 2026-09-01 (earliest plausible). Triggers documented in SPEC_FREEZE_V0_9_NOTES.md (RFC comment windows opened, external re-implementation reconciled, conformance corpus completeness audited).

RFC candidates from the OPEN matrix

Amendments most likely to need RFC treatment before v1.1+ promotion:

  • A11 — first-class union ADTs (replace the Result[T, Error] sentinel lowering).
  • A47 — Wasm Component Model wrappers (full wit-component).
  • A94 — sandboxed proc-macro execution surface.
  • A100 — per-call FsCap materialisation from sandbox manifest at the MtyIR lower.
  • A102 — agent affinity front-end syntax design.
  • A103 — lossless live agent migration design.

The OPEN-status amendments without architectural questions (A45 deprecation, A49 monomorphisation expansion, A80 labelled break, A81 trait-based iterators, A92 set-of-scopes hygiene, A93/A95 mty-pkg wiring) are tracked as ordinary backlog work rather than RFCs.