This PR adds support for detecting congruent terms in the (WIP) `grind`
tactic. It also introduces the `grind.debug` option, which, when set to
`true`, checks many invariants after each equivalence class is merged.
This option is intended solely for debugging purposes.
This PR adds a custom type and instance canonicalizer for the (WIP)
`grind` tactic. The `grind` tactic uses congruence closure but
disregards types, type formers, instances, and proofs. Proofs are
ignored due to proof irrelevance. Types, type formers, and instances are
considered supporting elements and are not factored into congruence
detection. Instead, `grind` only checks whether elements are
structurally equal, which, in the context of the `grind` tactic, is
equivalent to pointer equality. See new tests for examples where the
canonicalizer is important.
This PR ensures that `simp` and `dsimp` do not unfold definitions that
are not intended to be unfolded by the user. See issue #5755 for an
example affected by this issue.
Closes#5755
---------
Co-authored-by: Kim Morrison <kim@tqft.net>
This PR adds a new preprocessing step to the `grind` tactic:
universe-level normalization. The goal is to avoid missing equalities in
the congruence closure module.
This PR fixes a bug in `Lean.Meta.Closure` that would introduce
under-applied delayed assignment metavariables, which would keep them
from ever getting instantiated. This bug affected `match` elaboration
when the expected type contained postponed elaboration problems, for
example tactic blocks.
Closes#5925, closes#6354
This PR introduces the following features to the WIP `grind` tactic:
- `Expr` internalization.
- Congruence theorem cache.
- Procedure for adding new facts
- New tracing options
- New preprocessing steps: fold projections and eliminate dangling
`Expr.mdata`
This PR adds reserved names for congruence theorems used in the
simplifier and `grind` tactics. The idea is prevent the same congruence
theorems to be generated over and over again.
After update stage0, we must use the new API in the simplifier.
This PR ensures that the configuration in `Simp.Config` is used when
reducing terms and checking definitional equality in `simp`.
closes#5455
---------
Co-authored-by: Kim Morrison <kim@tqft.net>
This PR fixes a bug in the simplifier. It was producing terms with loose
bound variables when eliminating unused `let_fun` expressions.
This issue was affecting the example at #6374. The example is now timing
out.
This PR makes it harder to create "fake" theorems about definitions that
are stubbed-out with `sorry` by ensuring that each `sorry` is not
definitionally equal to any other. For example, this now fails:
```lean
example : (sorry : Nat) = sorry := rfl -- fails
```
However, this still succeeds, since the `sorry` is a single
indeterminate `Nat`:
```lean
def f (n : Nat) : Nat := sorry
example : f 0 = f 1 := rfl -- succeeds
```
One can be more careful by putting parameters to the right of the colon:
```lean
def f : (n : Nat) → Nat := sorry
example : f 0 = f 1 := rfl -- fails
```
Most sources of synthetic sorries (recall: a sorry that originates from
the elaborator) are now unique, except for elaboration errors, since
making these unique tends to cause a confusing cascade of errors. In
general, however, such sorries are labeled. This enables "go to
definition" on `sorry` in the Infoview, which brings you to its origin.
The option `set_option pp.sorrySource true` causes the pretty printer to
show source position information on sorries.
**Details:**
* Adds `Lean.Meta.mkLabeledSorry`, which creates a sorry that is labeled
with its source position. For example, `(sorry : Nat)` might elaborate
to
```
sorryAx (Lean.Name → Nat) false
`lean.foo.12.8.12.13.8.13._sorry._@.lean.foo._hyg.153
```
It can either be made unique (like the above) or merely labeled. Labeled
sorries use an encoding that does not impact defeq:
```
sorryAx (Unit → Nat) false (Function.const Lean.Name ()
`lean.foo.14.7.13.7.13.69._sorry._@.lean.foo._hyg.174)
```
* Makes the `sorry` term, the `sorry` tactic, and every elaboration
failure create labeled sorries. Most are unique sorries, but some
elaboration errors are labeled sorries.
* Renames `OmissionInfo` to `DelabTermInfo` and adds configuration
options to control LSP interactions. One field is a source position to
use for "go to definition". This is used to implement "go to definition"
on labeled sorries.
* Makes hovering over a labeled `sorry` show something friendlier than
that full `sorryAx` expression. Instead, the first hover shows the
simplified ``sorry `«lean.foo:48:11»``. Hovering over that hover shows
the full `sorryAx`. Setting `set_option pp.sorrySource true` makes
`sorry` always start with printing with this source position
information.
* Removes `Lean.Meta.mkSyntheticSorry` in favor of `Lean.Meta.mkSorry`
and `Lean.Meta.mkLabeledSorry`.
* Changes `sorryAx` so that the `synthetic` argument is no longer
optional.
* Gives `addPPExplicitToExposeDiff` awareness of labeled sorries. It can
set `pp.sorrySource` when source positions differ.
* Modifies the delaborator framework so that delaborators can set Info
themselves without it being overwritten.
Incidentally closes#4972.
Inspired by [this Zulip
thread](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Is.20a.20.60definition_wanted.60.20keyword.20possible.3F/near/477260277).
This PR removes the deprecated aliases `Int.div := Int.tdiv` and
`Int.mod := Int.tmod`. Later we will rename `Int.ediv` to `Int.div` and
`Int.emod` to `Int.mod`.
This PR removes unnecessary parameters from the funcion induction
principles. This is a breaking change; broken code can typically be adjusted
simply by passing fewer parameters.
Part 1, before stage0 update.
Closes#6320
This PR fixes a bug that could cause the `injectivity` tactic to fail in
reducible mode, which could cause unfolding lemma generation to fail
(used by tactics such as `unfold`). In particular,
`Lean.Meta.isConstructorApp'?` was not aware that `n + 1` is equivalent
to `Nat.succ n`.
Closes#5064
This PR implements `Simp.Config.implicitDefEqsProofs`. When `true`
(default: `true`), `simp` will **not** create a proof term for a
rewriting rule associated with an `rfl`-theorem. Rewriting rules are
provided by users by annotating theorems with the attribute `@[simp]`.
If the proof of the theorem is just `rfl` (reflexivity), and
`implicitDefEqProofs := true`, `simp` will **not** create a proof term
which is an application of the annotated theorem.
The default setting does change the existing behavior. Users can use
`simp -implicitDefEqProofs` to force `simp` to create a proof term for
`rfl`-theorems. This can positively impact proof checking time in the
kernel.
This PR also fixes an issue in the `split` tactic that has been exposed
by this feature. It was looking for `split` candidates in proofs and
implicit arguments. See new test for issue exposed by the previous
feature.
---------
Co-authored-by: Kim Morrison <kim@tqft.net>
This PR adds the builtin simproc `USize.reduceToNat` which reduces the
`USize.toNat` operation on literals less than `UInt32.size` (i.e.,
`4294967296`).
This PR deprecates `Fin.ofNat` in favour of `Fin.ofNat'` (which takes an
`[NeZero]` instance, rather than returning an element of `Fin (n+1)`).
After leaving the deprecation warning in place for some time, we will
then rename `ofNat'` back to `ofNat`.
This PR uses `Array.findFinIdx?` in preference to `Array.findIdx?` where
it allows converting a runtime bounds check to a compile time bounds
check.
(and some other minor cleanup)
This PR fixes a non-termination bug that occurred when generating the
match-expression equation theorems. The bug was triggered when the proof
automation for the equation theorem repeatedly applied `injection(` to
the same local declaration, as it could not be removed due to forward
dependencies. See issue #6067 for an example that reproduces this issue.
closes#6067
This PR modifies the signature of the functions `Nat.fold`,
`Nat.foldRev`, `Nat.any`, `Nat.all`, so that the function is passed the
upper bound. This allows us to change runtime array bounds checks to
compile time checks in many places.
This PR fixes a non-termination bug that occurred when generating the
match-expression splitter theorem. The bug was triggered when the proof
automation for the splitter theorem repeatedly applied `injection` to
the same local declaration, as it could not be removed due to forward
dependencies. See issue #6065 for an example that reproduces this issue.
closes#6065
This PR avoids runtime array bounds checks in places where it can
trivially be done at compile time.
None of these changes are of particular consequence: I mostly wanted to
learn how much we do this, and what the obstacles are to doing it less.
This PR does the same fix as #6104, but such that it doesn't break the
test/the file in `Plausible`. This is done by not creating unused let
binders in metavariable types that are made by `elimMVar`. (This is also
a positive thing for users looking at metavariable types, for example in
error messages)
We get rid of `skipAtMostNumBinders`. This function was originally
defined for the purpose of making this test work, but it is a hack
because it allows cycles in the metavariable context.
It would make sense to split these changes into 2 PRs, but I combined
them here to show that the combination of them closes#6013 without
breaking anything
Closes#6013
This PR replaces `Array.feraseIdx` and `Array.insertAt` with
`Array.eraseIdx` and `Array.insertIdx`, both of which take a `Nat`
argument and a tactic-provided proof that it is in bounds. We also have
`eraseIdxIfInBounds` and `insertIdxIfInBounds` which are noops if the
index is out of bounds. We also provide a `Fin` valued version of
`Array.findIdx?`. Together, these quite ergonomically improve the array
indexing safety at a number of places in the compiler/elaborator.
This PR fixes a bug at the definitional equality test (`isDefEq`). At
unification constraints of the form `c.{u} =?= c.{v}`, it was not trying
to unfold `c`. This bug did not affect the kernel.
closes#6117
This PR fixes an issue in the `injection` tactic. This tactic may
execute multiple sub-tactics. If any of them fail, we must backtrack the
partial assignment. This issue was causing the error: "`mvarId` is
already assigned" in issue #6066. The issue is not yet resolved, as the
equation generator for the match expressions is failing in the example
provided in this issue.
This PR fixes the caching infrastructure for `whnf` and `isDefEq`,
ensuring the cache accounts for all relevant configuration flags. It
also cleans up the `WHNF.lean` module and improves the configuration of
`whnf`.
This PR modifies `Lean.MVarId.replaceTargetDefEq` and
`Lean.MVarId.replaceLocalDeclDefEq` to use `Expr.equal` instead of
`Expr.eqv` when determining whether the expression has changed. This is
justified on the grounds that binder names and binder infos are
user-visible and affect elaboration.
This PR introduces date and time functionality to the Lean 4 Std.
Breaking Changes:
- `Lean.Data.Rat` is now `Std.Internal.Rat` because it's used by the
DateTime library.
---------
Co-authored-by: Markus Himmel <markus@himmel-villmar.de>
Co-authored-by: Mac Malone <tydeu@hatpress.net>
