This PR removes `tryMatchEquations` and `tryMatcher` from
`Lean.Meta.Tactic.Cbv.Main`, as both are already defined and used in
`Lean.Meta.Tactic.Cbv.ControlFlow`. The copies in `Main.lean` were
unreachable dead code.
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This PR renames `instance_reducible` to `implicit_reducible` and adds a
new
`backward.isDefEq.implicitBump` option to prepare for treating all
implicit
arguments uniformly during definitional equality checking.
## Changes
**Rename `instance_reducible` → `implicit_reducible`:**
- Rename `ReducibilityStatus.instanceReducible` constructor to
`implicitReducible`
- Register new `[implicit_reducible]` attribute, keep
`[instance_reducible]` as alias
- Rename `isInstanceReducible` → `isImplicitReducible` (with deprecated
aliases)
- Update all references across src/ and tests/
The rename reflects that this reducibility level is used not just for
instances
but for any definition that needs unfolding during implicit argument
resolution
(e.g., `Nat.add`, `Array.size`).
**Add `backward.isDefEq.implicitBump` option:**
- When `true` (+ `respectTransparency`), bumps transparency to
`.instances` for
ALL implicit arguments in `isDefEqArgs`, not just instance-implicit ones
- Defaults to `false` for staging compatibility — will be flipped to
`true` after
stage0 update
- Adds `// update me!` to `stage0/src/stdlib_flags.h` to trigger CI
stage0 update
## Follow-up (after stage0 update)
- Flip `backward.isDefEq.implicitBump` default to `true`
- Fix resulting test/module failures
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---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
## Summary
This PR adds documentation comments to the key transparency-related
definitions explaining the design rationale behind the transparency
hierarchy and the v4.29 changes:
- `TransparencyMode`: explains "try-hard" vs "speculative" `isDefEq`,
the transparency hierarchy (`none < reducible < instances < default <
all`), instance diamonds, and why implicit arguments received special
treatment
- `ReducibilityStatus`: documents each status with its corresponding
`TransparencyMode` level and typical use case
- `@[instance_reducible]`: explains decoupling of instance registration
from transparency
- `backward.isDefEq.respectTransparency`: explains the original
motivation for bumping transparency on implicit arguments, and why it
became a performance bottleneck
- `backward.whnf.reducibleClassField`: explains why `[reducible]` class
fields need special handling when the instance is only
`[instance_reducible]`
- `canUnfoldDefault` and `isDefEqArgs`: brief inline comments linking to
the design rationale
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---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
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>
This PR fixes an issue where commands that do not support incrementality
did not have their elaboration interrupted when a relevant edit is made
by the user. As all built-in variants of def/theorem share a common
incremental elaborator, this likely had negligible impact on standard
Lean files but could affect other use cases heavily relying on custom
commands such as Verso.
This PR fixes a bug where Lake recached artifacts already present within
the cache. As a result, Lake would attempt to overwrite the read-only
artifacts, causing a permission denied error.
This PR adds guidance to `.claude/CLAUDE.md` about the `module` +
`prelude` convention required for files in `src/Lean/`, `src/Std/`, and
`src/lake/Lake/`. CI enforces that these files contain `prelude`, but
with `prelude` nothing is auto-imported, so explicit `Init.*` imports
are needed for standard library features like `while`,
`String.startsWith`, etc.
🤖 Prepared with Claude Code
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This PR adds a "Copyright Headers" section to `.claude/CLAUDE.md`
instructing Claude to:
- Always use `date +%Y` for the copyright year instead of relying on
memory
- Match the copyright holder to what the author uses in other recent
files in the repo
- Skip copyright headers for test files in `tests/`
🤖 Prepared with Claude Code
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
This PR adds guidance to the release slash command to check actual PR
merge state (using `gh pr view`) when reporting status, rather than
relying on cached CI results. This prevents incorrectly reporting
already-merged PRs as still needing review.
🤖 Prepared with Claude Code
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
This PR removes the batteries dependency from ProofWidgets4 in
`release_repos.yml`. ProofWidgets4 no longer has any `require`
statements in its lakefile, so it doesn't depend on batteries.
🤖 Prepared with Claude Code
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
The `releases_drafts/` folder contained two entries that were already
covered in earlier releases:
- `module-system.md` — the module system was stabilized in v4.27.0
(https://github.com/leanprover/lean4/pull/11637)
- `environment.md` — the `importModules`/`finalizeImport` `loadExts`
change landed in v4.20.0 (https://github.com/leanprover/lean4/pull/6325)
Discovered while preparing the v4.29.0-rc1 release notes.
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This PR begins the development cycle for v4.30.0 by updating
`LEAN_VERSION_MINOR` to 30 in `src/CMakeLists.txt`.
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
This PR fixes a bug with `cache clean` where it would fail if the cache
directory does not exist.
This introduces a `removeDirAllIfExists` utility which is also now used
in `lake clean`. While `lake clean` did previously check for a
nonexistent build directory, this version should be more robust to
racing runs of `lake clean` as well.
This PR bundles some lemmas about hash maps into equivalences for easier
rewriting.
It still makes sense to have the individual directions since they
sometimes have weaker typeclass assumptions.
This PR improves the error messages produced by the `decide_cbv` tactic
by only reducing the left-hand side of the equality introduced by
`of_decide_eq_true`, rather than attempting to reduce both sides via
`cbvGoal`.
Previously, `evalDecideCbv` called `cbvGoalCore` which would try to
reduce both sides of `decide P = true` and leave a remaining goal on
failure, resulting in a generic error showing the mvar ID. Now, a
dedicated `cbvDecideGoal` function in `Cbv/Main.lean`:
- closes the goal immediately when the LHS reduces to `Bool.true`
- reports a clear error when the LHS reduces to `Bool.false`, telling
the user the proposition is false
- reports a clear error with the stuck expression when reduction cannot
complete
Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>
This PR improves the error message when `mvcgen` cannot resolve the name
of a spec theorem.
Example:
```lean
/-- error: Could not resolve spec theorem `abc` -/
#guard_msgs (error) in
example : True := by mvcgen [abc]
```
This used to print the syntax object representing the ident "abc".
This PR adds declaration names to leanchecker error messages to make
debugging easier when the kernel rejects a declaration.
Previously, leanchecker would only show the kernel error without
identifying which declaration failed:
```
uncaught exception: (kernel) type checker does not support loose bound variables
```
Now it includes the declaration name:
```
uncaught exception: while replaying declaration 'myDecl':
(kernel) type checker does not support loose bound variables
```
Fixes: #11937
---------
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: nomeata <148037+nomeata@users.noreply.github.com>
This PR adds `Std.Iter.toHashSet` and variants.
Included: variants starting from both monadic and non-monadic iterators,
producing extensional and non-extensional hash sets and tree sets.
Lemmas are included, showing that `it.toHashSet ~m HashSet.ofList
it.toList` (equivalence of hash sets) and `it.toExtHashSet =
ExtHashSet.ofList it.toList` (equality of extensional hash sets).
This PR adds the ability to register theorems with the `cbv_eval`
attribute in the reverse direction using the `←` modifier, mirroring the
existing `simp` attribute behavior. When `@[cbv_eval ←]` is used, the
equation `lhs = rhs` is inverted to `rhs = lhs`, allowing `cbv` to
rewrite occurrences of `rhs` to `lhs`.
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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
This PR shows `HashSet.ofList l ~m l.foldl (init := ∅) fun acc a =>
acc.insert a` (which is "just" the definition).
We also include the analogous statement about `insertMany`, and prove
this lemmas for dependent hash maps, normal hash maps, hash sets, as
well as the raw and extensional versions, and of course we also give the
corresponding tree map statements.
This PR adds tooling for profiling Lean programs with human-readable
function names in Firefox Profiler:
- **`script/lean_profile.sh`** — One-command pipeline: record with
samply, symbolicate, demangle, and open in Firefox Profiler
- **`script/profiler/lean_demangle.py`** — Faithful port of
`Name.demangleAux` from `NameMangling.lean`, with a postprocessor that
folds compiler suffixes into compact annotations (`[λ, arity↓]`, `spec
at context[flags]`)
- **`script/profiler/symbolicate_profile.py`** — Resolves raw addresses
via samply's symbolication API
- **`script/profiler/serve_profile.py`** — Serves demangled profiles to
Firefox Profiler without re-symbolication
- **`PROFILER_README.md`** — Documentation including a guide to reading
demangled names
### Example output in Firefox Profiler
| Raw C symbol | Demangled |
|---|---|
| `l_Lean_Meta_Sym_main` | `Lean.Meta.Sym.main` |
| `l_Lean_Meta_foo___redArg___lam__0` | `Lean.Meta.foo [λ, arity↓]` |
| `l_Lean_MVarId_withContext___at__...___spec__2___boxed` |
`Lean.MVarId.withContext [boxed] spec at Lean.Meta.bar[λ, arity↓]` |
Example:
<img width="1145" height="570" alt="image"
src="https://github.com/user-attachments/assets/8d23cc6a-1b89-4c60-9f4a-9f9f0f6e7697"
/>
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---------
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This PR fixes a bug where `grind [foo]` fails when the theorem `foo` has
a different universe variable name than the goal, even though universe
polymorphism should allow the universes to unify.
The issue was in `instantiateGroundTheorem` (used for theorems with no
quantified parameters), which was passing `thm.proof` directly instead
of calling `getProofWithFreshMVarLevels`. This meant ground theorems
retained their original universe level params instead of getting fresh
level metavariables that could unify with the goal's universe levels.
Fixes
https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/grind.20fails.20because.20of.20universe.20variable.20name🤖 Prepared with Claude Code
Co-authored-by: Claude <noreply@anthropic.com>
This PR fixes a release workflow bug where the reference-manual
repository would get tagged with a stale release notes title (e.g.,
still showing "-rc1" for a stable release).
The root cause was a sequencing issue: `release_steps.py` didn't update
the release notes title when bumping the reference-manual toolchain, and
`release_checklist.py` only checked the title while the bump PR was
open. Once merged, it went straight to tagging without rechecking.
Two fixes:
- `release_checklist.py`: add a title correctness check before tagging
reference-manual (blocks tagging if the title is wrong)
- `release_steps.py`: automatically update the `#doc` title line in the
release notes file when bumping reference-manual (handles both
RC-to-stable and RC-to-RC transitions)
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This PR proves that membership is preserved by eraseDups: an element
exists in the deduplicated list iff it was in the original.
Includes a helper lemma for the loop invariant of eraseDupsBy.loop to
establish the relationship between membership in the result, remaining
list, and accumulator.
The proof changed compared to the proposal discussed on Zulip:
https://leanprover.zulipchat.com/#narrow/channel/348111-batteries/topic/Where.20should.20List.2Emem_eraseDup.20and.20List.2Emem_eraseDups.20l.2E.2E.2E
Specifically, I could not apply @Rob23oba 's short proof suggestion
because it is located in `src/Init/Data`, a context where the `grind`
strategy is not yet available.
In the Zulip thread, there is a discussion about the
similarities/differences between Lean's `List.eraseDups` and Batteries'
`List.eraseDup`; whether it makes sense to keep both (perhaps with a
suitable renaming of Batterie's definition) or deprecate one (if any, it
would be Batteries' since it is currently unused whereas Lean's is used
across the board in Lean, Batteries, and Mathlib). See the Batteries PR:
https://github.com/leanprover-community/batteries/pull/1580
changelog-library
Closes https://github.com/leanprover/lean4/issues/11786
---------
Co-authored-by: Kim Morrison <477956+kim-em@users.noreply.github.com>
This PR introduces the theorem
`BitVec.sshiftRight_eq_setWidth_extractLsb_signExtend` theorem, proving
`x.sshiftRight n` is equivalent to first sign-extending `x`, extracting
the appropriate least significant bits, and then setting the width back
to `w`.
---------
Co-authored-by: Tobias Grosser <github@grosser.es>
This PR strips unneeded symbol names from libleanshared.so on Linux. It
appears that on other platforms the symbols names we are interested in
here are already removed by the linker.
This PR deprecates `extract_eq_drop_take` in favor of the more correct
name `extract_eq_take_drop`, so that we'll be able to use the old name
for a lemma `xs.extract start stop = (xs.take stop).drop start`. Until
the deprecation deadline has passed, this new lemma will be called
`extract_eq_drop_take'`.
This PR adds automatic ProofWidgets4 version pin updates to
`release_steps.py` when processing mathlib4. ProofWidgets4 uses
sequential version tags (`v0.0.X`) rather than toolchain-based tags
(`v4.X.Y`), so the existing regex that updates dependency versions in
lakefiles doesn't match it. This has caused CI failures in two
consecutive releases where the mathlib4 PR was created with a stale
ProofWidgets4 pin.
Changes:
- `script/release_steps.py`: Add `find_proofwidgets_tag()` to look up
the latest ProofWidgets4 tag compatible with the target toolchain, and
use it to update mathlib4's lakefile automatically
- `doc/dev/release_checklist.md`: Document the ProofWidgets4 pin update
step for mathlib4
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---------
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This PR fixes#12495 where equational theorem generation fails for
structurally recursive definitions using a Box-like wrapper around
nested inductives.
## Root Cause
`withInferTypeConfig` (in `InferType.lean`) ensures various MetaM config
settings (`beta`, `iota`, `zeta`, `zetaHave`, `zetaDelta`, `proj`) are
enabled during type inference, but was missing `etaStruct`. When
`inferType` is called from a context where `etaStruct` is disabled —
such as inside `simpMatch` (which sets `etaStruct := .none` via
`SimpM.run` → `withSimpContext`) — `whnf` cannot eta-expand structure
values needed for recursor iota reduction.
Concretely, projecting from a type like `Rec.rec_2 ... base` (where
`base : Box Rec`) requires eta-expanding `base` to `Box.mk base.data` so
the `Box` recursor can reduce. With `etaStruct := .none`,
`toCtorWhenStructure` skips the eta-expansion, leaving `whnf` stuck and
`inferProjType` unable to recognize the resulting type as a structure.
## Fix
Add `etaStruct := .all` to the config settings ensured by
`withInferTypeConfig`, alongside the existing `beta`, `iota`, `zeta`,
`zetaHave`, `zetaDelta`, and `proj` settings. This also allows reverting
the workaround (`try/catch` around `simpMatch?`) that was added in the
first commit.
## Test plan
- [x] Existing test `tests/lean/run/issue12495.lean` passes
- [x] Full test suite (3561 tests) passes with 0 failures
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---------
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Avoids wasted work in `setImportedEntries`. This is still not ideal as
exts that are set but never/rarely read still have a cost proportional
to the number of imported modules but it's an easy step forward.
This PR removes the unnecessary and potentially broken handling of
`let`s by zeta-reduction in Sym-based `mvcgen`.
It turns out to be unnecessary for the benchmarks so far, so there is a
lack of motivation to publicize `betaRevS` which would be needed to fix
it.
This PR ensures `isDefEq` does not increase the transparency mode to
`.default` when checking whether implicit arguments are definitionally
equal. The previous behavior was creating scalability problems in
Mathlib. That said, this is a very disruptive change. The previous
behavior can be restored using the command
```
set_option backward.isDefEq.respectTransparency false
```
