This PR fixes an `AppBuilder` exception in the `cbv` tactic when
simplifying projections whose projection function is dependent (closes
#12457).
Previously, `handleProj` unconditionally used `mkCongrArg` to prove `e.i
= e'.i` from `e = e'`, but `mkCongrArg` requires a non-dependent
function. For dependent projections (e.g., `fun x => x.2 : (x :
String.Slice) → x.1.Pos`), this would fail.
Now, `handleProj` first checks whether the projection function type is
non-dependent (a simple arrow). If so, it proceeds with `mkCongrArg` as
before. Otherwise, it falls back to:
1. Attempting to reduce the projection directly.
2. If reduction fails, using a heterogeneous congruence lemma
(`mkHCongr`) converted to an equality via `mkEqOfHEq`, provided the
original and rewritten struct are definitionally equal.
This PR verifies all of the `String` iterators except for the bytes
iterator by relating them to `String.toList`.
Along the way we define `String.posLE` and `String.posLT` analogously to
`String.posGE` and `String.posGT` and redefine `String.prev` to go
through `String.posLT`.
We also define and verify `String.positionsFrom` and
`String.revPositionsFrom`, which are the obvious generaliziations of
`String.positions` and `String.revPositions` starting at a positions
other than the start/end.
Finally, we get various lemmas about strings and positions, including
some nice induction principles `String.Pos.next_induction` and
`String.Pos.prev_induction`.
Of course, we also have all of the analogous results for `String.Slice`.
This PR adds a simplification rule for `Task.get (Task.pure x) = x` into
the LCNF simplifier. This
ensures that we avoid touching the runtime for a `Task` that instantly
gets destructed anyways.
This PR adds the attribute `@[univ_out_params]` for specifying which
universe levels should be treated as output parameters. By default, any
universe level that does not occur in any input parameter is considered
an output parameter.
This PR sets the `irreducible` attribute before generating the equations
for recursive definitions. This prevents these equations to be marked as
`defeq`, which could lead to `simp` generation proofs that do not type
check at default transparency.
This issue is surfacing more easily since well-founded recursion on
`Nat` is implemented with a dedicated fix point operator (#7965). Before
that, `WellFounded.fix` was used, which is inherently not reducing, so
we did get the desired result even without the explicit reducibility
setting.
Fixes#12398.
This PR adds a finishing `decide_cbv` tactic, which applies
`of_decide_eq_true` and then tries to discharge the remaining goal using
`cbv`.
Stacked on top of #12408.
---------
Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>
This PR adds caching to `replaceRecApps`, the procedure responsible for
replacing recursive applications for wellfounded recursion, improving
performance when many references to the same recursive call exist, e.g.
when recursive calls exist in proof terms.
Closes#12404
---------
Co-authored-by: Joachim Breitner <mail@joachim-breitner.de>
This PR adds a user facing `cbv` tactic that can be used outside of the
`conv` mode.
Example usage:
```lean4
example : "hello" ++ " " ++ "world" = "hello world" := by cbv
```
---------
Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>
This PR gives a proof of `LawfulToForwardSearcherModel` for `Slice`
patterns, which amounts to proving that our implementation of KMP is
correct.
Note that this PR also changes the KMP implementation to make it
slightly more efficient and easier to verify. I also have a correctness
proof for the old implementation, so there were no bugs in the old
implementation.
This PR fixes a bug in `mvcgen` caused by incomplete `match` splitting.
In particular, if a program `match s with ...` matches on a state
variable `s` (presumably the result of a call to `get`), then `s` will
also occur in the stateful goal `H ⊢ₛ wp⟦match s with ...⟧ Q s`
*outside* the program expression; this was not anticipated before.
This PR adds `mvcgen` support for specifications in the local context.
Example:
```lean
import Std.Tactic.Do
open Std.Do
set_option mvcgen.warning false
def foo (x : Id Nat → Id Nat) : Id Nat := do
let r₁ ← x (pure 42)
let r₂ ← x (pure 26)
pure (r₁ + r₂)
theorem foo_spec
(x : Id Nat → Id Nat)
(x_spec : ∀ (k : Id Nat) (_ : ⦃⌜True⌝⦄ k ⦃⇓r => ⌜r % 2 = 0⌝⦄), ⦃⌜True⌝⦄ x k ⦃⇓r => ⌜r % 2 = 0⌝⦄) :
⦃⌜True⌝⦄ foo x ⦃⇓r => ⌜r % 2 = 0⌝⦄ := by
mvcgen [foo, x_spec] <;> grind
def bar (k : Id Nat) : Id Nat := do
let r ← k
if r > 30 then return 12 else return r
example : ⦃⌜True⌝⦄ foo bar ⦃⇓r => ⌜r % 2 = 0⌝⦄ := by
mvcgen [foo_spec, bar] -- unfold `bar` and automatically apply the spec for the higher-order argument `k`
```
This PR improves the slice API with lemmas for `drop`/`take` operations
on `Subarray` and more lemmas about `Std.Slice.fold`, `Std.Slice.foldM`
and `Std.Slice.forIn`. It also changes the `simp` and `grind`
annotations for `Slice`-related lemmas. Lemmas converting between slices
of different shapes are no longer `simp`/`grind`-annotated because they
often complicated lemmas and hindered automation.
This PR adds a custom simproc to handle `Decidable.rec`, where we force
the rewrite in the argument of the `Decidable` type, that normally is
not rewritten due to being a subsingleton.
Closes#12386
This PR develops custom simprocs for dealing with `ite`/`dite`
expressions in `cbv` tactics, based on equivalent simprocs from
`Sym.simp`, with the difference that if the condition is not reduced to
`True`/`False`, we make use of the decidable instance and calculate to
what the condition reduces to.
Stacked on top of #12391.
This PR adds `IO.FS.Metadata.numLinks`, which contains the number of
hard links to a file.
This changes the implementation of `System.FilePath.metadata` and
`System.FilePath.symlinkMetadata` to use libuv. Otherwise, `st_nlink`
was not properly set on Windows. This also has the side benefit of
provided sub-second precision for file times on Windows (fulfilling an
old TODO). Also, while libuv supports `lstat` for Windows, enabling that
is left to a future PR.
This PR fixes a platform inconsistency in `IO.FS.removeFile` where it
could not delete read-only files on Windows.
The implementation now uses `uv_fs_unlink` instead of `std::remove`, as
libuv can delete read-only files. The PR also fixes a inconsistency in
`IO_test.lean` where it would generate files in the wrong directory when
run interactively.
---------
Co-authored-by: Markus Himmel <markus@himmel-villmar.de>
This PR adds a few unification hints that we will need after
`backward.isDefEq.respectTransparency` is `true` by default.
See #12338
It was part of #12179.
This PR moves the elaboration of structure/class Verso docstrings until
after the fact that it's a class is registered, so code samples in the
docstring can use it as a class. Redundant addition of structure and
constructor docstrings are also removed, because they're already handled
in MutualInductive.lean.
Closes#11651
This PR treats the first character of the first line of a docstring as
being in the leftmost column, even if it physically is not. This allows
left-column items like headers to be used even after spaces. It also
detects the indentation of the entire docstring, using it as the
zero-point for indentation sensitive syntax such as headers.
Closes#12067.
This PR fixes poor error reporting from Verso docstrings. Before, if the
Verso parser didn't consume the whole docstring, then Lean would try to
parse the closing -/ and fail; this would lead to backtracking and an
assumption that the docstring must be non-Verso, with only the non-Verso
commands like #guard_msgs as possibilities. Now, the input is always
consumed.
Closes#12118.
This PR implements better support for unfolding class fields marked as
`reducible`. For example, we want to mark fields that are types such as
```lean
MonadControlT.stM : Type u -> Type u
```
The motivation is similar to our heuristic that type definitions should
be abbreviations.
Now, suppose we want to unfold `stM m (ExceptT ε m) α` using the
`.reducible` transparency setting, we want the result to be `stM m m
(MonadControl.stM m (ExceptT ε m) α)` instead of
`(instMonadControlTOfMonadControl m m (ExceptT ε m)).1 α`. The latter
would defeat the intent of marking the field as reducible, since the
instance `instMonadControlTOfMonadControl` is `[instance_reducible]` and
the resulting term would be stuck when using `.reducible` transparency
mode.
**Remark**: This feature introduces a few breakages in core and Mathlib.
So, it is disabled for now in this PR. To enable, we must use
`set_option backward.whnf.reducibleClassField true`
This PR adds two benchmarks (sieve of Eratosthenes, removing duplicates
from the list) and one test (a function with sublinear complexity
defined via well-founded recursion evaluated on large naturals with up
to `60` digits).
The tests have been suggested by @b-mehta.
This PR changes the semantics of `inline` annotations in the compiler.
The behavior of the original `@[inline]` attribute remains the same but
the function `inline` now comes with a restriction that it can only use
declarations that are local to the current module. This comes as a
preparation to pulling the compiler out into a separate process.
Closes: #12334
This PR changes the handling of over-applied cases expressions in
`ToLCNF` to avoid generating function declarations that are called
immediately. For example, `ToLCNF` previously produced this:
```lean-4
set_option trace.Compiler.init true
/--
trace: [Compiler.init] size: 4
def test x y : Bool :=
fun _y.1 _y.2 : Bool :=
cases x : Bool
| PUnit.unit =>
fun _f.3 a : Bool :=
return a;
let _x.4 := _f.3 _y.2;
return _x.4;
let _x.5 := _y.1 y;
return _x.5
-/
#guard_msgs in
def test (x : Unit) (y : Bool) : Bool :=
x.casesOn (fun a => a) y
```
which is now simplified to
```lean-4
set_option trace.Compiler.init true
/--
trace: [Compiler.init] size: 3
def test x y : Bool :=
cases x : Bool
| PUnit.unit =>
let a := y;
return a
-/
#guard_msgs in
def test (x : Unit) (y : Bool) : Bool :=
x.casesOn (fun a => a) y
```
This is especially relevant for #8309 because there `dite` is defined as
an over-applied `Bool.casesOn`.
This PR adds the option `doc.verso.module`. If set, it controls whether
module docstrings use Verso syntax. If not set, it defaults to the value
of the `doc.verso` option.
Closes#12070.
This PR fixes an issue on new NeoVim versions that would cause the
language server to display an error when using certain code actions.
(For some reason, NeoVim recently decided to diverge from VS Code in
terms of when it emits code action resolution requests, which means that
not setting the `data?` field won't preclude NeoVim from emitting a
request anymore, which in turn means that the server can't resolve the
code action.)
This PR ensures `simp` does not "simplify" instances by default. The old
behavior can be retrieved by using `simp +instances`. This PR is similar
to #12195, but for `dsimp`.
The backward compatibility flag for `dsimp` also deactivates this new
feature.
```
set_option backward.dsimp.instances true
```
Applying `simp` (and `dsimp`) to instances creates non-standard
instances, and this creates all sorts of problems in Mathlib.
---------
Co-authored-by: Henrik Böving <hargonix@gmail.com>
Co-authored-by: Sebastian Graf <sgraf1337@gmail.com>
Co-authored-by: Kim Morrison <kim@tqft.net>
