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5160 commits

Author SHA1 Message Date
Kim Morrison
a6ed0d640d
feat: add #guard_panic command and substring option for #guard_msgs (#11908)
This PR adds two features to the message testing commands:

## `#guard_panic` command

A new `#guard_panic` command that succeeds if the nested command
produces a panic message. Unlike `#guard_msgs`, it does not check the
exact message content, only that a panic occurred.

This is useful for testing commands that are expected to panic, where
the exact panic message text may be volatile. It is particularly useful
when minimizing a panic discovered "in the wild", while ensuring the
panic behaviour is preserved.

## `substring := true` option for `#guard_msgs`

Adds a `substring := true` option to `#guard_msgs` that checks if the
docstring appears as a substring of the output (after whitespace
normalization), rather than requiring an exact match. This is useful
when you only care about part of the message.

Example:
```lean
/-- Unknown identifier -/
#guard_msgs (substring := true) in
example : α := x
```

## Refactoring

Also refactors `runAndCollectMessages` as a shared helper function used
by both `#guard_msgs` and `#guard_panic`.

🤖 Prepared with Claude Code

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
2026-01-07 01:34:49 +00:00
Kim Morrison
c358b0c734
feat: add guards for grind patterns for getElem?_eq_none theorems (#11761)
This PR adds some `grind_pattern` `guard` conditions to potentially
expensive theorems.
2026-01-05 08:55:02 +00:00
Kim Morrison
8207919728
chore: cleanup grind List tests (#11903)
Some of these tests were last investigated a long time ago: happily many
of the failing tests now work due to subsequent improvements to grind.
2026-01-05 05:02:33 +00:00
Kim Morrison
b46688d683
feat: add Nat.gcd_left_comm and Int.gcd_left_comm (#11901)
This PR adds `gcd_left_comm` lemmas for both `Nat` and `Int`:

- `Nat.gcd_left_comm`: `gcd m (gcd n k) = gcd n (gcd m k)`
- `Int.gcd_left_comm`: `gcd a (gcd b c) = gcd b (gcd a c)`

These lemmas establish the left-commutativity property for gcd,
complementing the existing `gcd_comm` and `gcd_assoc` lemmas.

Upstreamed from
https://github.com/leanprover-community/mathlib4/pull/33235

🤖 Prepared with Claude Code

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
2026-01-05 03:12:50 +00:00
Kim Morrison
fab1897f28
feat: add with_unfolding_none tactic (#11880)
This PR adds a `with_unfolding_none` tactic that sets the transparency
mode to `.none`, in which no definitions are unfolded. This complements
the existing `with_unfolding_all` tactic and provides tactic-level
access to the `TransparencyMode.none` added in
https://github.com/leanprover/lean4/pull/11810.

🤖 Prepared with Claude Code

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
2026-01-03 08:36:51 +00:00
Henrik Böving
4eb5b5776d
perf: inline IsUTF8FirstByte (#11872)
This PR marks IsUTF8FirstByte as inline.

I have a use case where it shows up significantly in the profile.
2026-01-02 11:21:54 +00:00
Leonardo de Moura
d4563a818f
feat: simplifier for Sym (#11856)
This PR adds the basic infrastructure for the structural simplifier used
by the symbolic simulation (`Sym`) framework.
2026-01-01 04:34:50 +00:00
Paul Reichert
e8781f12c0
feat: use MonadAttach in the takeWhileM and dropWhileM iterator combinators (#11852)
This PR changes the definition of the iterator combinators `takeWhileM`
and `dropWhileM` so that they use `MonadAttach`. This is only relevant
in rare cases, but makes it sometimes possible to prove such combinators
finite when the finiteness depends on properties of the monadic
predicate.
2025-12-31 12:38:21 +00:00
Paul Reichert
1590a72913
feat: make FinitenessRelation part of the public API (#11789)
This PR makes the `FinitenessRelation` structure, which is helpful when
proving the finiteness of iterators, part of the public API. Previously,
it was marked internal and experimental.
2025-12-29 20:45:41 +00:00
Leonardo de Moura
2234c91163
feat: add TransparencyMode.none (#11810)
This PR adds a new transparency mode `.none` in which no definitions are
unfolded.
2025-12-27 03:10:17 +00:00
Henrik Böving
4d2647f9c7
fix: foldlM mismatch part 2 (#11779)
This PR fixes an oversight in the initial #11772 PR.

Closes #11778.
2025-12-23 10:29:20 +00:00
Leonardo de Moura
a471f005d6
feat: add [grind norm] and [grind unfold] attributes (#11776)
This PR adds the attributes `[grind norm]` and `[grind unfold]` for
controlling the `grind` normalizer/preprocessor.

The `norm` modifier instructs `grind` to use a theorem as a
normalization rule. That is, the theorem is applied during the
preprocessing step. This feature is meant for advanced users who
understand how the preprocessor and `grind`'s search procedure interact
with each other.
New users can still benefit from this feature by restricting its use to
theorems that completely eliminate a symbol from the goal. Example:
```lean
theorem max_def : max n m = if n ≤ m then m else n
```
For a negative example, consider:
```lean
opaque f : Int → Int → Int → Int
theorem fax1 : f x 0 1 = 1 := sorry
theorem fax2 : f 1 x 1 = 1 := sorry
attribute [grind norm] fax1
attribute [grind =] fax2

example (h : c = 1) : f c 0 c = 1 := by
  grind -- fails
```
In this example, `fax1` is a normalization rule, but it is not
applicable to the input goal since `f c 0 c` is not an instance of `f x
0 1`. However, `f c 0 c` matches the pattern `f 1 x 1` modulo the
equality `c = 1`. Thus, `grind` instantiates `fax2` with `x := 0`,
producing the equality `f 1 0 1 = 1`, which the normalizer simplifies to
`True`. As a result, nothing useful is learned. In the future, we plan
to include linters to automatically detect issues like these. Example:
```lean
opaque f : Nat → Nat
opaque g : Nat → Nat

@[grind norm] axiom fax : f x = x + 2
@[grind norm ←] axiom fg : f x = g x

example : f x ≥ 2 := by grind
example : f x ≥ g x := by grind
example : f x + g x ≥ 4 := by grind
```

The `unfold` modifier instructs `grind` to unfold the given definition
during the preprocessing step. Example:
```lean
@[grind unfold] def h (x : Nat) := 2 * x
example : 6 ∣ 3*h x := by grind
```
2025-12-23 03:54:35 +00:00
Henrik Böving
a847b13b1a
fix: implemented_by Array.foldlM behavior when stop > start (#11774)
This PR fixes a mismatch between the behavior of `foldlM` and
`foldlMUnsafe` in the three array
types. This mismatch is only exposed when manually specifying a `stop`
value greater than the size
of the array and only exploitable through `native_decide`.

The mismatch was introduced as part of
4ba21ea10c which introduced
`foldlMUnsafe` and thus likely a mistake when building the `unsafe`
implementation instead of a
specification mistake.

Closes #11773
2025-12-22 23:46:45 +00:00
Leonardo de Moura
186a81627b
fix: Array.foldlMUnsafe bug (#11772)
This PR a bug in the optimized and unsafe implementation of
`Array.foldlM`.

Issue was reported here:

https://leanprover.zulipchat.com/#narrow/channel/113488-general/topic/Array.2Efoldl.20bug.20.28can.20prove.20False.29/near/565077432
2025-12-22 23:00:16 +00:00
Leonardo de Moura
0d2a574f96
feat: user-defined grind attributes (#11765)
This PR implements user-defined `grind` attributes. They are useful for
users that want to implement tactics using the `grind` infrastructure
(e.g., `progress*` in Aeneas). New `grind` attributes are declared using
the command
```lean
register_grind_attr my_grind
```
The command is similar to `register_simp_attr`. After the new attribute
is declared. Recall that similar to `register_simp_attr`, the new
attribute cannot be used in the same file it is declared.
```lean
opaque f : Nat → Nat
opaque g : Nat → Nat

@[my_grind] theorem fax : f (f x) = f x := sorry

example theorem fax2 : f (f (f x)) = f x := by
  fail_if_success grind
  grind [my_grind]
```

TODO: remove leftovers after update stage0
2025-12-22 02:57:25 +00:00
Kim Morrison
a7562bc578
feat: add guarded grind_pattern to List.eq_nil_of_length_eq_zero (#11760)
This PR allows `grind` to use `List.eq_nil_of_length_eq_zero` (and
`Array.eq_empty_of_size_eq_zero`), but only when it has already proved
the length is zero.
2025-12-22 00:05:58 +00:00
Kim Morrison
c86b10d141
chore: add grind pattern guide for Sublist.eq_of_length_le (#11762)
This PR moves the grind pattern from `Sublist.eq_of_length` to the
slightly more general `Sublist.eq_of_length_le`, and adds a grind
pattern guard so it only activates if we have a proof of the hypothesis.
2025-12-22 00:01:33 +00:00
Luisa Cicolini
eb11ccb234
feat: lemmas around BitVec.extractLsb' and BitVec.extractLsb (#11728)
This PR introduces some additional lemmas around `BitVec.extractLsb'`
and `BitVec.extractLsb`.

---------

Co-authored-by: Tobias Grosser <github@grosser.es>
Co-authored-by: Tobias Grosser <tobias@grosser.es>
2025-12-18 11:27:27 +00:00
Paul Reichert
4e656ea8e9
refactor: move Std.Range to Std.Legacy.Range (#11438)
This PR renames the namespace `Std.Range` to `Std.Legacy.Range`. Instead
of using `Std.Range` and `[a:b]` notation, the new range type `Std.Rco`
and its corresponding `a...b` notation should be used. There are also
other ranges with open/closed/infinite boundary shapes in
`Std.Data.Range.Polymorphic` and the new range notation also works for
`Int`, `Int8`, `UInt8`, `Fin` etc.
2025-12-18 02:07:33 +00:00
Paul Reichert
5ef0207a85
refactor: remove IteratorCollect (#11706)
This PR removes the `IteratorCollect` type class and hereby simplifies
the iterator API. Its limited advantages did not justify the complexity
cost.
2025-12-17 23:02:33 +00:00
Paul Reichert
a1b8ffe31b
feat: improve MPL support for loops over iterators, fix MPL spec priorities (#11716)
This PR adds more MPL spec lemmas for all combinations of `for` loops,
`fold(M)` and the `filter(M)/filterMap(M)/map(M)` iterator combinators.
These kinds of loops over these combinators (e.g. `it.mapM`) are first
transformed into loops over their base iterators (`it`), and if the base
iterator is of type `Iter _` or `IterM Id _`, then another spec lemma
exists for proving Hoare triples about it using an invariant and the
underlying list (`it.toList`). The PR also fixes a bug that MPL always
assigns the default priority to spec lemmas if `Std.Tactic.Do.Syntax` is
not imported and a bug that low-priority lemmas are preferred about
high-priority ones.

For context, the MPL bug was related to the fact that the `Attr.spec`
syntax is not built-in. Therefore, Lean falls back to the `Attr.simple`
syntax, which *basically* also works, but which stores the priority at a
different position. The routine to extract the priority does not
consider this and so it falls back to the default priority given an
`Attr.simple` syntax object.
2025-12-17 22:49:42 +00:00
Henrik Böving
f21f8d96f9
perf: improve auto completion and fuzzy matching (#11630)
This PR improves the performance of autocompletion and fuzzy matching by
introducing an ASCII fast path into one of their core loops and making
Char.toLower/toUpper more efficient.

Co-authored-by: Rob23oba <152706811+Rob23oba@users.noreply.github.com>
2025-12-17 16:04:05 +00:00
Paul Reichert
489f8acd77
feat: get-elem tactic support for subarrays (#11710)
This PR extends the get-elem tactic for ranges so that it supports
subarrays. Example:
```lean
example {a : Array Nat} (h : a.size = 28) : Id Unit := do
  let mut x := 0
  for h : i in *...(3 : Nat) do
    x := a[1...4][i]
```
2025-12-17 13:44:17 +00:00
Paul Reichert
08f0d12ffb
feat: add lemmas about Int ranges (#11705)
This PR provides many lemmas about `Int` ranges, in analogy to those
about `Nat` ranges. A few necessary basic `Int` lemmas are added. The PR
also removes `simp` annotations on `Rcc.toList_eq_toList_rco`,
`Nat.toList_rcc_eq_toList_rco` and consorts.
2025-12-17 10:04:28 +00:00
Luisa Cicolini
06d2390fb3
feat: add BitVec.cpop and lemmas (#11257)
This PR adds the definition of `BitVec.cpop`, which relies on the more
general `BitVec.cpopNatRec`, and build some theory around it. The name
`cpop` aligns with the [RISCV ISA
nomenclature](https://msyksphinz-self.github.io/riscv-isadoc/#_cpop).

Co-authored-by: @tobiasgrosser, @bollu

---------

Co-authored-by: Tobias Grosser <tobias@grosser.es>
Co-authored-by: Tobias Grosser <github@grosser.es>
Co-authored-by: Siddharth <siddu.druid@gmail.com>
2025-12-17 09:51:24 +00:00
Paul Reichert
3ac9bbb3d8
feat: MPL specs for loops over iterators (#11693)
This PR makes it possible to verify loops over iterators. It provides
MPL spec lemmas about `for` loops over pure iterators. It also provides
spec lemmas that rewrite loops over `mapM`, `filterMapM` or `filterM`
iterator combinators into loops over their base iterator.
2025-12-17 09:36:44 +00:00
Joachim Breitner
118160bf07
refactor: handle irrefutable patterns in match compilation individually (#11695)
This PR refactors match compilation, to handle “side-effect free”
patterns (`.var`, `.inaccessible`, `.as`) eagerly and for each
alternative separately. The idea is that there should be less interplay
between different alternatives, and prepares the ground for #11105.

This may cause some corner case match statements to compiler or fail
compile that behaved differently before. For example, it can now use a
sparse case where previously was using a full case, and pattern
completeness may not be clear to lean now. On the other hand, using a
sparse case can mean that match statements mixing matching in indicies
with matching on the indexed datatype can work.
2025-12-17 09:02:17 +00:00
Paul Reichert
e2617903f8
feat: MonadAttach (#11532)
This PR adds the new operation `MonadAttach.attach` that attaches a
proof that a postcondition holds to the return value of a monadic
operation. Most non-CPS monads in the standard library support this
operation in a nontrivial way. The PR also changes the `filterMapM`,
`mapM` and `flatMapM` combinators so that they attach postconditions to
the user-provided monadic functions passed to them. This makes it
possible to prove termination for some of these for which it wasn't
possible before. Additionally, the PR adds many missing lemmas about
`filterMap(M)` and `map(M)` that were needed in the course of this PR.
2025-12-16 18:57:00 +00:00
Markus Himmel
7ba21c4d1b
fix: incorrect inherit_doc (#11704)
This PR fixes an incorrect `inherit_doc` in `Init.System.IO`.
2025-12-16 17:30:01 +00:00
Leonardo de Moura
12c282b1e9
doc: add link to reference manual in grind docstring (#11700)
This PR adds a link to the `grind` docstring. The link directs users to
the section describing `grind` in the reference manual.

<img width="840" height="354" alt="image"
src="https://github.com/user-attachments/assets/8efedc53-26cd-4f2c-8d47-a9d3a324e579"
/>
2025-12-16 15:35:55 +00:00
Sebastian Graf
5f4d724c2d
feat: abstract metavariables when generalizing match motives (#8099) (#11696)
This PR improves `match` generalization such that it abstracts
metavariables in types of local variables and in the result type of the
match over the match discriminants. Previously, a metavariable in the
result type would silently default to the behavior of `generalizing :=
false`, and a metavariable in the type of a free variable would lead to
an error (#8099). Example of a `match` that elaborates now but
previously wouldn't:
```lean
example (a : Nat) (ha : a = 37) :=
    (match a with | 42 => by contradiction | n => n) = 37
```
This is because the result type of the `match` is a metavariable that
was not abstracted over `a` and hence generalization failed; the result
is that `contradiction` cannot pick up the proof `ha : 42 = 37`.
The old behavior can be recovered by passing `(generalizing := false)`
to the `match`.

Furthermore, programs such as the following can now be elaborated:
```lean
example (n : Nat) : Id (Fin (n + 1)) :=
  have jp : ?m := ?rhs
  match n with
  | 0 => ?jmp1
  | n + 1 => ?jmp2
  where finally
  case m => exact Fin (n + 1) → Id (Fin (n + 1))
  case jmp1 => exact jp ⟨0, by decide⟩
  case jmp2 => exact jp ⟨n, by omega⟩
  case rhs => exact pure
```
This is useful for the `do` elaborator.

Fixes #8099.
2025-12-16 14:34:29 +00:00
Henrik Böving
bd5d750780
chore: fix BitVec docstring typo (#11694)
Closes #11680
2025-12-16 08:54:14 +00:00
Joachim Breitner
9b49b6b68d
fix: let grind handle Nat.ctorIdx (#11670)
This PR fixes the `grind` support for `Nat.ctorIdx`. Nat constructors
appear in `grind` as offsets or literals, and not as a node marked
`.constr`, so handle that case as well.
2025-12-15 10:26:16 +00:00
Paul Reichert
c79d74d9a1
refactor: move Iter and others from Std.Iterators to Std (#11446)
This PR moves many constants of the iterator API from `Std.Iterators` to
the `Std` namespace in order to make them more convenient to use. These
constants include, but are not limited to, `Iter`, `IterM` and
`IteratorLoop`. This is a breaking change. If something breaks, try
adding `open Std` in order to make these constants available again. If
some constants in the `Std.Iterators` namespace cannot be found, they
can be found directly in `Std` now.
2025-12-15 08:24:12 +00:00
Leonardo de Moura
62b900e8ef
feat: basic equality propagation for IntModule in grind (#11677)
This PR adds basic support for equality propagation in `grind linarith`
for the `IntModule` case. This covers only the basic case. See note in
the code.
We remark this feature is irrelevant for `CommRing` since `grind ring`
already has much better support for equality propagation.
2025-12-14 22:40:11 +00:00
Evan Chen
429e09cd82
doc: trivial typo in Grind/Attr.lean (#11676)
This PR fixes typo "the the custom pattern" -> "the custom pattern".
2025-12-14 20:12:47 +00:00
Junyan Xu
fb6c96e54b
chore: expose Nat.log2 (#11401)
Necessary for kernel reduction of `binaryRec`, see
leanprover-community/mathlib4#30144
2025-12-14 05:19:29 +00:00
Joachim Breitner
0bfbb71796
perf: restore kernel-reduction friendly Nat.hasNotBit definition (#11657)
This PR improves upon #11652 by keeping the kernel-reduction-optimized
definition.
2025-12-13 17:00:33 +00:00
Leonardo de Moura
38c401cf3b
feat: new Int operations in grind (#11656)
This PR adds support for `Int.sign`, `Int.fdiv`, `Int.tdiv`, `Int.fmod`,
`Int.tmod`, and `Int.bmod` to `grind`. These operations are just
preprocessed away. We assume that they are not very common in practice.
Examples:
```lean
example {x y : Int} : y = 0 → (x.fdiv y) = 0 := by grind
example {x y : Int} : y = 0 → (x.tdiv y) = 0 := by grind
example {x y : Int} : y = 0 → (x.fmod y) = x := by grind
example {x y : Int} : y = 1 → (x.fdiv (2 - y)) = x := by grind
example {x : Int} : x > 0 → x.sign = 1 := by grind
example {x : Int} : x < 0 → x.sign = -1 := by grind
example {x y : Int} : x.sign = 0 → x*y = 0 := by grind
```

See #11622
2025-12-13 14:55:34 +00:00
Leonardo de Moura
a2ceebe200
feat: semiring * propagators in grind (#11653)
This PR adds propagation rules corresponding to the `Semiring`
normalization rules introduced in #11628. The new rules apply only to
non-commutative semirings, since support for them in `grind` is limited.
The normalization rules introduced unexpected behavior in Mathlib
because they neutralize parameters such as `one_mul`: any theorem
instance associated with such a parameter is reduced to `True` by the
normalizer.
2025-12-13 14:32:34 +00:00
Leonardo de Moura
292b74b0a4
chore: update grind docstring (#11654)
This PR updates the `grind` docstring. It was still mentioning `cutsat`
which has been renamed to `lia`. This issue was reported during ItaLean.
2025-12-13 14:32:30 +00:00
Joachim Breitner
d76752ffb8
feat: grind support for .ctorIdx (#11652)
This PR teaches `grind` how to reduce `.ctorIdx` applied to
constructors. It can also handle tasks like
```
xs ≍ Vec.cons x xs' → xs.ctorIdx = 1
```
thanks to a `.ctorIdx.hinj` theorem (generated on demand).
2025-12-13 13:32:19 +00:00
Joe Hendrix
ac7b95da86
feat: port Batteries.WF for executable well-founded fixpoints (#11620)
This PR ports Batteries.WF to Init.WFC for executable well-founded
fixpoints. It introduces `csimp` theorems to replace the recursors and
non-executable definitions with executable definitions.

This ocassionally comes up on Zulip as it prevents admiting definitions
generated from well-founded induction. (e.g., [#lean4 > Computable
WellFounded.fix](https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/Computable.20WellFounded.2Efix/with/529347861)
and [#mathlib4 > Why Nat.find is computable, when Wellfounded.fix
isn't?](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Why.20Nat.2Efind.20is.20computable.2C.20when.20Wellfounded.2Efix.20isn't.3F/with/545143617)).

This was motivated by running into poor elaboration performance with
recursive definitions involving complex inductive types generated by a
custom elaborator. It would be helpful to explore bypassing the
elaborator and generating elaborated terms directly, but this requires
an executable fixpoint (such as `WellFounded.fixC` introduced in
batteries).
2025-12-12 18:22:54 +00:00
Paul Reichert
9d7d15b276
feat: lint coercions that are deprecated or banned in core (#11511)
This PR implements a linter that warns when a deprecated coercion is
applied. It also warns when the `Option` coercion or the
`Subarray`-to-`Array` coercion is used in `Init` or `Std`. The linter is
currently limited to `Coe` instances; `CoeFun` instances etc. are not
considered.

The linter works by collecting the `Coe` instance declaration names that
are being expanded in `expandCoe?` and storing them in the info tree.
The linter itself then analyzes the info tree and checks for banned or
deprecated coercions.
2025-12-12 15:09:13 +00:00
Kim Morrison
ad02aa159c
chore: remove ≥6 month old deprecations (#11627) 2025-12-12 10:40:04 +00:00
Leonardo de Moura
8220baf6db
feat: add a few Semiring normalization rules to grind (#11628)
This PR adds a few `*` normalization rules for `Semiring`s to `grind`.
2025-12-12 09:10:49 +00:00
Wojciech Różowski
3937af3d75
feat: add a lemma relating minKey? and min? for DTreeMap (#11528)
This PR adds lemmas relating `minKey?` and `min?` on the keys list for
all `DTreeMap` and other containers derived from it.
2025-12-12 08:03:00 +00:00
Eric Wieser
646df6ba16
feat: add lemmas about EStateM.run (#11600)
This PR adds a few lemmas about `EStateM.run` on basic operations.
2025-12-12 03:00:17 +00:00
Kim Morrison
552fa10a60
feat: @[suggest_for ℤ] and @[suggest_for ℚ] annotations (#11596)
This PR adds `@[suggest_for ℤ]` on `Int` and `@[suggest_for ℚ]` on
`Rat`, following the pattern established by `@[suggest_for ℕ]` on `Nat`
in #11554.


🤖 Prepared with Claude Code

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
2025-12-12 02:59:35 +00:00
Robert Maxton
7d2dbe8787
feat: expose decidable_of_bool (#11625)
This PR adds `@[expose]` to `decidable_of_bool` so that
proofs-by-`decide` elsewhere that reduce to `decidable_of_bool` continue
to reduce.
2025-12-12 02:57:49 +00:00