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Lean 4 fork for HoTT-compatible kernel extensions (Path types, transport, HITs). Maintained against upstream leanprover/lean4.
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Joachim Breitner 7fa7ec1887
fix: instantiate mvars after synthesizing inductive type header (#12558) 
This PR fixes a `(kernel) declaration has metavariables` error that
occurred when a `by` tactic was used in a dependent inductive type index
that refers to a previous index:

```lean
axiom P : Prop
axiom Q : P → Prop
-- Previously gave: (kernel) declaration has metavariables 'Foo'
inductive Foo : (h : P) → (Q (by exact h)) → Prop
```

The root cause: `elabDepArrow` calls `mkForallFVars [h_fvar] body`
before the `by` tactic's metavariable `?m` is resolved. Since `h_fvar`
is in `?m`'s local context, `elimMVarDeps` creates a delayed assignment
`?newMVar #[h_fvar] := ?m`. After `synthesizeSyntheticMVarsNoPostponing`
assigns `?m := h_fvar`, `instantiateMVars` can resolve the delayed
assignment (substituting `h_fvar` with the actual argument, `bvar 0`, in
the pending value), yielding the correct type `∀ (h : P), Q (bvar 0) →
Prop`. The fix is to call `instantiateMVars` on the header type right
after `synthesizeSyntheticMVarsNoPostponing` in `elabHeadersAux`.

Fixes #12543.

🤖 This PR was created with [Claude Code](https://claude.ai/claude-code).

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-02-18 15:29:33 +00:00
.claude chore: add module/prelude guidance to CLAUDE.md (#12542) 2026-02-18 00:57:20 +00:00
.github fix: nightly revision date logic and mathlib trigger auth (#12463) 2026-02-13 06:03:15 +00:00
doc chore: improve release command PR status checking (#12536) 2026-02-17 21:21:30 +00:00
images
releases_drafts chore: remove stale release draft notes (#12518) 2026-02-17 19:56:23 +00:00
script chore: remove batteries dependency from ProofWidgets4 in release_repos.yml (#12535) 2026-02-17 20:35:20 +00:00
src fix: instantiate mvars after synthesizing inductive type header (#12558) 2026-02-18 15:29:33 +00:00
stage0 chore: update stage0 2026-02-18 07:56:34 +00:00
tests fix: instantiate mvars after synthesizing inductive type header (#12558) 2026-02-18 15:29:33 +00:00
.gitattributes doc: grove: update and add String data (#11551) 2025-12-08 16:49:37 +00:00
.gitignore chore: add .vscode/settings.json to .gitignore (#10795) 2025-10-16 07:08:41 +00:00
.gitpod.Dockerfile chore: add gitpod configuration (#6382) 2024-12-15 21:38:13 +00:00
.gitpod.yml chore: add gitpod configuration (#6382) 2024-12-15 21:38:13 +00:00
.ignore
CMakeLists.txt chore: reformat all cmake files (#12218) 2026-01-28 18:23:08 +00:00
CMakePresets.json chore: CI: enable leak sanitizer again (#11339) 2025-11-27 18:32:35 +00:00
CODEOWNERS chore: make @hargoniX code owner of the compiler (#10732) 2025-10-10 04:43:38 +00:00
CONTRIBUTING.md doc: triage 2024-07-26 18:24:06 +02:00
flake.lock chore: update to c++20 (#12117) 2026-02-11 01:17:40 +00:00
flake.nix chore: update to c++20 (#12117) 2026-02-11 01:17:40 +00:00
lean-toolchain doc: VS Code dev setup (#2961) 2023-11-30 08:35:03 +00:00
lean.code-workspace chore: lean.code-workspace: fix terminal cwd (#10802) 2025-10-16 20:19:12 +00:00
LICENSE
LICENSES feat: ship cadical (#4325) 2024-08-23 09:13:27 +00:00
README.md doc: update URLs that are currently pointing to redirects (#10397) 2025-09-17 15:50:07 +00:00
RELEASES.md chore: updates to release_checklist.md (#7817) 2025-04-04 03:45:36 +00:00

README.md

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