This PR adds a code action for `grind` parameters. We need to use
`set_option grind.param.codeAction true` to enable the option. The PR
also adds a modifier to instruct `grind` to use the "default" pattern
inference strategy.
This PR reduces noise in the 'Equivalence classes' section of the
`grind` diagnostics. It now uses a notion of *support expressions*.
Right now, it is hard-coded, but we will probably make it extensible in
the future. The current definition is
- `match`, `ite` and `dite`-applications. They have builtin support in
`grind`.
- Cast-like applications used by `grind`: `toQ`, `toInt`, `Nat.cast`,
`Int.cast`, and `cast`
- `grind` gadget applications (e.g., `Grind.nestedDecidable`)
- Projections of constructors (e.g., `{ x := 1, y := 2}.x`)
- Auxiliary arithmetic terms constructed by solvers such as `cutsat` and
`ring`.
If an equivalence class contains at most one non-support term, it goes
into the “others” bucket. Otherwise, we display the non-support elements
and place the support terms in a child node.
**BEFORE**:
<img width="1397" height="1558" alt="image"
src="https://github.com/user-attachments/assets/4fd4de31-7300-4158-908b-247024381243"
/>
**AFTER**:
<img width="840" height="340" alt="image"
src="https://github.com/user-attachments/assets/05020f34-4ade-49bf-8ccc-9eb0ba53c861"
/>
**Remark**: No information is lost; it is just grouped differently."
This PR adds an alternative implementation of `Deriving Ord` based on
comparing `.ctorIdx` and using a dedicated matcher for comparing same
constructors (added in #10152). The new option
`deriving.ord.linear_construction_threshold` sets the constructor count
threshold (10 by default) for using the new construction.
It also (unconditionally) changes the implementation for enumeration
types to simply compare the `ctorIdx`.
This PR implements `mvcgen invariants?` for providing initial invariant
skeletons for the user to flesh out. When the loop body has an early
return, it will helpfully suggest `Invariant.withEarlyReturn ...` as a
skeleton.
```lean
def mySum (l : List Nat) : Nat := Id.run do
let mut acc := 0
for x in l do
acc := acc + x
return acc
/--
info: Try this:
invariants
· ⇓⟨xs, acc⟩ => _
-/
#guard_msgs (info) in
theorem mySum_suggest_invariant (l : List Nat) : mySum l = l.sum := by
generalize h : mySum l = r
apply Id.of_wp_run_eq h
mvcgen invariants?
all_goals admit
def nodup (l : List Int) : Bool := Id.run do
let mut seen : HashSet Int := ∅
for x in l do
if x ∈ seen then
return false
seen := seen.insert x
return true
/--
info: Try this:
invariants
· Invariant.withEarlyReturn (onReturn := fun r acc => _) (onContinue := fun xs acc => _)
-/
#guard_msgs (info) in
theorem nodup_suggest_invariant (l : List Int) : nodup l ↔ l.Nodup := by
generalize h : nodup l = r
apply Id.of_wp_run_eq h
mvcgen invariants?
all_goals admit
```
This PR fixes a potential miscompilation when using non-exposed type
definitions using the module system by turning it into a static error. A
future revision may lift the restriction by making the compiler metadata
independent of the current module.
This PR makes `mvcgen` reduce through `let`s, so that it progresses over
`(have t := 42; fun _ => foo t) 23` by reduction to `have t := 42; foo
t` and then introducing `t`.
This PR adds an alternative implementation of `DerivingBEq` based on
comparing `.ctorIdx` and using a dedicated matcher for comparing same
constructors (added in #10152), to avoid the quadratic overhead of the
default match implementation. The new option
`deriving.beq.linear_construction_threshold` sets the constructor count
threshold (10 by default) for using the new construction. Such instances
also allow `deriving ReflBEq, LawfulBeq`, although these proofs for
these properties are still quadratic.
This PR adds the `reduceCtorIdx` simproc which recognizes and reduces
`ctorIdx` applications. This is not on by default yet because it does
not use the discrimination tree (yet).
This PR redefines `String` to be the type of byte arrays `b` for which
`b.IsValidUtf8`.
This moves the data model of strings much closer to the actual data
representation at runtime.
In the near future, we will
- provide variants of `String.Pos` and `Substring` that only allow for
valid positions
- redefine all `String` functions to be much closer to their C++
implementations
In the near-to-medium future we will then provide comprehensive
verification of `String` based on these refactors.
This PR adds support the Count Trailing Zeros operation `BitVec.ctz` to
the bitvector library and to `bv_decide`, relying on the existing `clz`
circuit. We also build some theory around `BitVec.ctz` (analogous to the
theory existing for `BitVec.clz`) and introduce lemmas
`BitVec.[ctz_eq_reverse_clz, clz_eq_reverse_ctz, ctz_lt_iff_ne_zero,
getLsbD_false_of_lt_ctz, getLsbD_true_ctz_of_ne_zero,
two_pow_ctz_le_toNat_of_ne_zero, reverse_reverse_eq,
reverse_eq_zero_iff]`.
`ctz` operation is common in numerous compiler intrinsics (see
[here](https://clang.llvm.org/docs/LanguageExtensions.html#intrinsics-support-within-constant-expressions))
and architectures (see
[here](https://en.wikipedia.org/wiki/Find_first_set)).
---------
Co-authored-by: Siddharth <siddu.druid@gmail.com>
This PR adds `reprove N by T`, which effectively elaborates `example
type_of% N := by T`. It supports multiple identifiers. This is useful
for testing tactics.
🤖 Generated with [Claude Code](https://claude.ai/code)
---------
Co-authored-by: Claude <noreply@anthropic.com>
This PR enables the new E-matching pattern inference heuristic for
`grind`, implemented in PR #10422.
**Important**: Users can still use the old pattern inference heuristic
by setting:
```lean
set_option backward.grind.inferPattern true
```
In PR #10422, we introduced the new modifier `@[grind!]` for enabling
the minimal indexable subexpression condition. This option can now also
be set in `grind` parameters. Example:
```lean
opaque f : Nat → Nat
opaque fInv : Nat → Nat
axiom fInv_f : fInv (f x) = x
/-- trace: [grind.ematch.pattern] fInv_f: [f #0] -/
#guard_msgs in
set_option trace.grind.ematch.pattern true in
example {x y} : f x = f y → x = y := by
/-
The modifier `!` instructs `grind` to use the minimal indexable subexpression
(i.e., `f x` in this case).
-/
grind [!fInv_f]
```
This PR refines and clarifies the `meta` phase distinction in the module
system.
* `meta import A` without `public` now has the clarified meaning of
"enable compile-time evaluation of declarations in or above `A` in the
current module, but not downstream". This is now checked statically by
enforcing that public meta defs, which therefore may be referenced from
outside, can only use public meta imports, and that global evaluating
attributes such as `@[term_parser]` can only be applied to public meta
defs.
* `meta def`s may no longer reference non-meta defs even when in the
same module. This clarifies the meta distinction as well as improves
locality of (new) error messages.
* parser references in `syntax` are now also properly tracked as meta
references.
* A `meta import` of an `import` now properly loads only the `.ir` of
the nested module for the purposes of execution instead of also making
its declarations available for general elaboration.
* `initialize` is now no longer being run on import under the module
system, which is now covered by `meta initialize`.
This PR ensures users can select the "minimal indexable subexpression"
condition in `grind` parameters. Example, they can now write `grind [!
-> thmName]`. `grind?` will include the `!` modifier whenever users had
used `@[grind!]`. This PR also fixes a missing case in the new pattern
inference procedure.
It also adjusts some `grind` annotations and tests in preparation for
setting the new pattern inference heuristic as the new default.
This PR changes the order of steps tried when proving equational
theorems for structural recursion. In order to avoid goals that `split`
cannot handle, avoid unfolding the LHS of the equation to `.brecOn` and
`.rec` until after the RHS has been split into its final cases.
Fixes: #10195
This PR lets the `split` tactic generalize discriminants that are not
free variables and proofs using `generalize`. If the only
non-fvar-discriminants are proofs, then this avoids the more elaborate
generalization strategy of `split`, which can fail with dependent
motives, thus mitigating issue #10424.
This PR implements the new E-matching pattern inference heuristic for
`grind`. It is not enabled yet. You can activate the new behavior using
`set_option backward.grind.inferPattern false`. Here is a summary of the
new behavior.
* `[grind =]`, `[grind =_]`, `[grind _=_]`, `[grind <-=]`: no changes;
we keep the current behavior.
* `[grind ->]`, `[grind <-]`, `[grind =>]`, `[grind <=]`: we stop using
the *minimal indexable subexpression* and instead use the first
indexable one.
* `[grind! <mod>]`: behaves like `[grind <mod>]` but uses the minimal
indexable subexpression restriction. We generate an error if the user
writes `[grind! =]`, `[grind! =_]`, `[grind! _=_]`, or `[grind! <-=]`,
since there is no pattern search in these cases.
* `[grind]`: it tries `=`, `=_`, `<-`, `->`, `<=`, `=>` with and without
the minimal indexable subexpression restriction. For the ones that work,
we generate a code action to encourage users to select the one they
prefer.
* `[grind!]`: it tries `<-`, `->`, `<=`, `=>` using the minimal
indexable subexpression restriction. For the ones that work, we generate
a code action to encourage users to select the one they prefer.
* `[grind? <mod>]`: where `<mod>` is one of the modifiers above, it
behaves like `[grind <mod>]` but also displays the pattern.
Example:
```lean
/--
info: Try these:
• [grind =] for pattern: [f (g #0)]
• [grind =_] for pattern: [r #0#0]
• [grind! ←] for pattern: [g #0]
-/
#guard_msgs in
@[grind] axiom fg₇ : f (g x) = r x x
```
This PR adds a normalizer for non-commutative semirings to `grind`.
Examples:
```lean
open Lean.Grind
variable (R : Type u) [Semiring R]
example (a b c : R) : a * (b + c) = a * c + a * b := by grind
example (a b : R) : (a + 2 * b)^2 = a^2 + 2 * a * b + 2 * b * a + 4 * b^2 := by grind
example (a b : R) : b^2 + (a + 2 * b)^2 = a^2 + 2 * a * b + b * (1+1) * a * 1 + 5 * b^2 := by grind
example (a b : R) : a^3 + a^2*b + a*b*a + b*a^2 + a*b^2 + b*a*b + b^2*a + b^3 = (a+b)^3 := by grind
```
This PR changes the automation in `deriving_LawfulEq_tactic_step` to use
`with_reducible` when asserting the shape of the goal using `change`, so
that we do not accidentally unfold `x == x'` calls here. Fixes#10416.
This PR adds the ability to do `deriving ReflBEq, LawfulBEq`. Both
classes have to listed in the `deriving` clause. For `ReflBEq`, a simple
`simp`-based proof is used. For `LawfulBEq`, a dedicated,
syntax-directed tactic is used that should work for derived `BEq`
instances. This is meant to work with `deriving BEq` (but you can try to
use it on hand-rolled `@[methods_specs] instance : BEq…` instances).
Does not support mutual or nested inductives.
This PR fixes a bug where definitions with nested proofs that contain
`sorry` might not report "warning: declaration uses 'sorry'" if the
proof has the same type as another nested proof from a previous
declaration. The bug only affected log messages; `#print axioms` would
still correctly report uses of `sorryAx`.
The fix is that now the abstract nested proofs procedure does not
consult the aux lemma cache if the proof contains a `sorry`.
Closes#10196
This PR gives anonymous constructor notation (`⟨x,y⟩`) an error recovery
mechanism where if there are not enough arguments then synthetic sorries
are inserted for the missing arguments and an error is logged, rather
than outright failing.
Closes#9591.
This PR adds the `reduceBEq` and `reduceOrd` simprocs. They rewrite
occurrences of `_ == _` resp. `Ord.compare _ _` if both arguments are
constructors and the corresponding instance has been marked with
`@[method_specs]` (introduced in #10302), which now by default is the
case for derived instances.
This PR introduces the `@[specs]` attribute. It can be applied to
(certain) type class instances and define “specification theorems” for
the class’ operations, by taking the equational theorems of the
implementation function mentioned in the type class instance and
rephrasing them in terms of the overloaded operations. Fixes#5295.
Example:
```
inductive L α where
| nil : L α
| cons : α → L α → L α
def L.beqImpl [BEq α] : L α → L α → Bool
| nil, nil => true
| cons x xs, cons y ys => x == y && L.beqImpl xs ys
| _, _ => false
@[method_specs] instance [BEq α] : BEq (L α) := ⟨L.beqImpl⟩
/--
info: theorem instBEqL.beq_spec_2.{u_1} : ∀ {α : Type u_1} [inst : BEq α] (x_2 : α) (xs : L α) (y : α) (ys : L α),
(L.cons x_2 xs == L.cons y ys) = (x_2 == y && xs == ys)
-/
#guard_msgs(pass trace, all) in
#print sig instBEqL.beq_spec_2
```
It also introduces the `method_specs_norm` simpset to allow registering
further normalization of the theorems. The intended use of this is to
rewrite, say, `Append.append` to the `HAppend.hAppend` (i.e. `++`) that
the user wants to see. Library annotations to follow in a separate PR.
This PR makes the builtin Verso docstring elaborators bootstrap
correctly, adds the ability to postpone checks (which is necessary for
resolving forward references and bootstrapping issues), and fixes a
minor parser bug.
This PR implements sanity checks in the `grind ring` module to ensure
the instances synthesized by type class resolution are definitionally
equal to the corresponding ones in the `grind` core classes. The
definitional equality test is performed with reduction restricted to
reducible definitions and instances.
This PR fixes an issue where the "eta feature" in the app elaborator,
which is invoked when positional arguments are skipped due to named
arguments, results in variables that can be captured by those named
arguments. Now the temporary local variables that implement this feature
get fresh names. The names used for the closed lambda expression still
use the original parameter names.
Closes#6373
This PR enables using `notation` items in
`infix`/`infixl`/`infixr`/`prefix`/`postfix`. The motivation for this is
to enable being able to use `pp.unicode`-aware parsers. A followup PR
can combine core parsers as such:
```lean
infixr:30 unicode(" ∨ ", " \\/ ") => Or
```
Continuation of #10373.
This PR modifies pretty printing of `fun` binders, suppressing the safe
shadowing feature among the binders in the same `fun`. For example,
rather than pretty printing as `fun x x => 0`, we now see `fun x x_1 =>
0`. The calculation is done per `fun`, so for example `fun x => id fun x
=> 0` pretty prints as-is, taking advantage of safe shadowing.
The motivation for this change is that many users have reported that
safe shadowing within the same `fun` is confusing.
