I did not introduce `inductTheoremSuffix` etc, it seems more direct to
just spell out the suffix here. If we ever change it there are many
occurrences where they need to be changed anyways, so the definition
doesn't seem to save much work or add that much robustness.
we keep running into examples where working with well-founded recursion
is slow because defeq checks (which are all over the place, including
failing ones that are back-tracked) unfold well-founded definitions.
The definition of a function defined by well-founded recursion should be
an implementation detail that should only be peeked inside by the
equation generator and the functional induction generator.
We now mark the mutual recursive function as irreducible (if the user
did not
set a flag explicitly), and use `withAtLeastTransparency .all` when
producing
the equations.
Proofs can be fixed by using rewriting, or – a bit blunt, but nice for
adjusting
existing proofs – using `unseal` (a.k.a. `attribute [local
semireducible]`).
Mathlib performance does not change a whole lot:
http://speed.lean-fro.org/mathlib4/compare/08b82265-75db-4a28-b12b-08751b9ad04a/to/16f46d5e-28b1-41c4-a107-a6f6594841f8
Build instructions -0.126 %, four modules with significant instructions
decrease.
To reduce impact, these definitions were changed:
* `Nat.mod`, to make `1 % n` reduce definitionally, so that `1` as a
`Fin 2` literal
works nicely. Theorems with larger `Fin` literals tend to need a `unseal
Nat.modCore`
https://github.com/leanprover/lean4/pull/4098
* `List.ofFn` rewritten to be structurally recursive and not go via
`Array.ofFn`:
https://github.com/leanprover-community/batteries/pull/784
Alternative designs explored were
* Making `WellFounded.fix` irreducible.
One benefit is that recursive functions with equal definitions (possibly
after
instantiating fixed parameters) are defeq; this is used in mathlib to
relate
[`OrdinalApprox.gfpApprox`](https://leanprover-community.github.io/mathlib4_docs/Mathlib/SetTheory/Ordinal/FixedPointApproximants.html#OrdinalApprox.gfpApprox)
with `.lfpApprox`.
But the downside is that one cannot use `unseal` in a
targeted way, being explicit in which recursive function needs to be
reducible here.
And in cases where Lean does unwanted unfolding, we’d still unfold the
recursive
definition once to expose `WellFounded.fix`, leading to large terms for
often no good
reason.
* Defining `WellFounded.fix` to unroll defintionally once before hitting
a irreducible
`WellFounded.fixF`. This was explored in #4002. It shares most of the
ups and downs
with the previous variant, with the additional neat benefit that
function calls that
do not lead to recursive cases (e.g. a `[]` base case) reduce nicely.
This means that
the majority of existing `rfl` proofs continue to work.
Issue #4051, which demonstrates how badly things can go if wf recursive
functions can be
unrolled, showed that making the recursive function irreducible there
leads to noticeably
faster elaboration than making `WellFounded.fix` irreducible; this is
good evidence that
the present PR is the way to go.
This fixes https://github.com/leanprover/lean4/issues/3988
---------
Co-authored-by: Leonardo de Moura <leomoura@amazon.com>
Fixes#3270 by moving the deprecation check from
`Lean.Elab.Term.mkConsts` to `Lean.Elab.Term.mkConst`, so
`Lean.Elab.Term.mkBaseProjections`, `.elabAppLValsAux`, `.elabAppFn`,
and `.elabForIn` also hit the check. Not all of these really need to hit
the check, so I'll run `!bench` to see if it's a problem.
As [reported on
Zulip](https://leanprover.zulipchat.com/#narrow/stream/341532-lean4-dev/topic/Find.20references.20broken.20in.20lean.20core/near/437051935).
The `mainModuleName` was being set incorrectly when browsing lean core
sources, resulting in failure of cross-file server requests like "Find
References". Because the `srcSearchPath` is generated asynchronously, we
store it as a `Task Name` which is resolved some time before the header
is finished parsing. (I don't think the `.get` here will ever block,
because the srcSearchPath will be ready by the time the initial command
snap is requested.)
---------
Co-authored-by: Sebastian Ullrich <sebasti@nullri.ch>
This issue was affecting several Mathlib files.
@mattrobball @semorrison This is a different solution for the issue. The
comment at `Extra.lean` describes the new solution and documents the new
issues found with the previous one.
closes#4085
This is still experimental, but it implements identifier support in auto
tactics "in the obvious way". It also converts `quoteAutoTactic` to
generate Expr directly instead of going via syntax (this doesn't have
any effect other than increasing compile cost AFAICT).
even when rewriting the type of `h` becuase there is no expected type.
(When there is an expected type, it already tried both orientations.)
Also feeble attempt to include this information in the docstring without
writing half a manual chapter.
when dealing with well-founded recursive definitions, `tryURefl` isn't
going to be that useful and possibly slow. So disable that code path
when doing well-founded recursion.
(This is a variant of #4025 where I tried using `with_reducible` to
limit the impact of slow unfolding, but if we can get away with
disabling it complete, then even better.)
It currently only reports how many times each declaration has been
unfolded, and how often the `isDefEq` heuristic for `f a =?= f b` has
been used. Only counters above the threshold are reported.
The subst notation substitues in the expected type, if present, or in
the type of the argument, if no expected type is known.
If there is an expected type it already fails if it cannot find the
equations' left hand side or right hand side. But if the expected type
is not known and the equation's lhs is not present in the second
argument's type, it will happily do a no-op-substitution.
This is inconsistent and unlikely what the user intended to do, so we
now print an error message now.
This still only looks for the lhs; search for the rhs as well seems
prudent, but I’ll leave that for a separate PR, to better diagnose the
impact on mathlib.
This triggers a small number of pointless uses of subst in mathlib, see
https://github.com/leanprover-community/mathlib4/pull/12451
This makes `exact?%` behave like `by exact?` rather than `by apply?`.
If the underlying function `librarySearch` finds a suggestion which
closes the goal, use it (and add a code action). Otherwise log an error
and use `sorry`. The error is either
```text
`exact?%` didn't find any relevant lemmas
```
or
```text
`exact?%` could not close the goal. Try `by apply` to see partial suggestions.
```
---
[Zulip](https://leanprover.zulipchat.com/#narrow/stream/287929-mathlib4/topic/Useful.20term.20elaborators/near/434863856)
---------
Co-authored-by: Scott Morrison <scott.morrison@gmail.com>
<!--
# Read this section before submitting
* Ensure your PR follows the [External Contribution
Guidelines](https://github.com/leanprover/lean4/blob/master/CONTRIBUTING.md).
* Please make sure the PR has excellent documentation and tests. If we
label it `missing documentation` or `missing tests` then it needs
fixing!
* Include the link to your `RFC` or `bug` issue in the description.
* If the issue does not already have approval from a developer, submit
the PR as draft.
* The PR title/description will become the commit message. Keep it
up-to-date as the PR evolves.
* If you rebase your PR onto `nightly-with-mathlib` then CI will test
Mathlib against your PR.
* You can manage the `awaiting-review`, `awaiting-author`, and `WIP`
labels yourself, by writing a comment containing one of these labels on
its own line.
* Remove this section, up to and including the `---` before submitting.
-->
See RFC #3644 for a discussion of design choices.
Closes#3644
Adds a `--json` option to the `lean` CLI. When used, the Lean frontend
will print messages as JSON objects using the default `ToJson` encoding
for the `Message` structure. This allows consumers (such as Lake) to
handle Lean output in a more intelligent, well-structured way.
`Message` has been refactored into `BaseMessage`, `Message`, and
`SerialMessage` to enable deriving `ToJson`/ `FromJson` instances
automatically for `BaseMessage` / `SerialMessage`. `SerialMessage` is a
`Message` with its `MessageData` eagerly serialized to a `String`.
previously, the empty `MessageData` (`m!""`) was used to indicate “no
message”, and `throwTacticEx` would format the message differently then.
But the semantics of `MessageData.isEmpty` isn't entirely clear in the
presence of lazy message data (e.g. `.ofPPFormat`).
So to avoid wondering what `isEmpty` should do there, let's simply use
an optional argument to `throwTacticEx` and get rid of
`MessageData.isEmpty`.
This PR partly addresses #3458, by adding an option `autoPromoteIndices`
to turn off the promotion of fixed indices to parameters. The actual fix
for the issue is in a separate PR #3591.
Because nested inductive datatypes parameters cannot contain local
variables, it is often desirable for a fixed index to not be promoted,
as to allow free variables in that place. See example in `3458_1.lean`
* Replaces the unused `Lean.PrettyPrinter.ppConst` with
`MessageData.ofConst` (which similarly avoids an unnecessary `@`) and
that further generates a hover for the constant
* Uses this in `TryThis.addRewriteSuggestion`, so that `rw?` suggestions
don't have unnecessary `@`s.
* Add `MessageData.signature`, as a wrapper around
`PrettyPrinter.signature`, using the same machinery to generate hovers
for constants, improving the hover behaviour in #check so that we get
second order pop-up for constants in the signature. (Not sure how to
write tests for second order hovers, so there is no test for this.)
Adds the ability to show a diff when `guard_msgs` fails, using the
histogram diff algorithm pioneered in jgit. This algorithm tends to
produce more user-friendly diffs, but it can be quadratic in the worst
case. Empirically, the quadratic case of this implementation doesn't
seem to be slow enough to matter for messages smaller than hundreds of
megabytes, but if it's ever a problem, we can mitigate it the same way
jgit does by falling back to Myers diff.
See lean/run/guard_msgs.lean in the tests directory for some examples of
its output.
While implementing #3925, I noticed that the performance of the
`textDocument/semanticTokens/full` request is *extremely* bad due to a
quadratic implementation. Specifically, on my machine, computing the
full semantic tokens for `Lean/Elab/Do.lean` took a full 5s. In
practice, this means that while elaborating the file, one core is
entirely busy with computing the semantic tokens for the file.
This PR fixes this performance bug by re-implementing the semantic token
handling, reducing the latency for `Lean/Elab/Do.lean` from 5s to 60ms.
As a result, the overly cautious refresh latency of 5s in #3925 can
easily be reduced to 2s again.
Since the previous semantic tokens implementation used a very brittle
hack to identify projections, this PR also changes the projection
notation elaboration to augment the `InfoTree` syntax for the field of a
projection with a special syntax node of kind
`Lean.Parser.Term.identProjKind`. With this syntax kind, projection
fields can now easily be identified in the `InfoTree`.
while trying to help a user who was facing an unhelpful
```
omega did not find a contradiction:
[0, 0, 0, 0, 1, -1] ∈ [1, ∞)
[0, 0, 0, 0, 0, 1] ∈ [0, ∞)
[0, 0, 0, 0, 1] ∈ [0, ∞)
[1, -1] ∈ [1, ∞)
[0, 0, 0, 1] ∈ [0, ∞)
[0, 1] ∈ [0, ∞)
[1] ∈ [0, ∞)
[0, 0, 0, 1, 1] ∈ [-1, ∞)
```
I couldn’t resist and wrote a pretty-printer for these problem that
shows the linear combination as such, and includes the recognized atoms.
This is especially useful since oftem `omega` failures stem from failure
to recognize atoms as equal. In this case, we now get:
```
omega-failure.lean:19:2-19:7: error: omega could not prove the goal:
a possible counterexample may satisfy the constraints
d - e ≥ 1
e ≥ 0
d ≥ 0
a - b ≥ 1
c ≥ 0
b ≥ 0
a ≥ 0
c + d ≥ -1
where
a := ↑(sizeOf xs)
b := ↑(sizeOf x)
c := ↑(sizeOf x.fst)
d := ↑(sizeOf x.snd)
e := ↑(sizeOf xs)
```
and this might help the user make progress (e.g. by using `case x`
first, and investingating why `sizeOf xs` shows up twice)
Reusing the best profiling UI out there
Usage:
```
lean -Dtrace.profiler=true -Dtrace.profiler.output=profile.json foo.lean ...
```
then open `profile.json` in https://profiler.firefox.com/.
See also `script/collideProfiles.lean` for minimizing and merging
profiles.
Implements a new method to generate instance names for anonymous
instances that uses a heuristic that tends to produce shorter names. A
design goal is to make them relatively unique within projects and
definitely unique across projects, while also using accessible names so
that they can be referred to as needed, both in Lean code and in
discussions.
The new method also takes into account binders provided to the instance,
and it adds project-based suffixes. Despite this, a median new name is
73% its original auto-generated length. (Compare: [old generated
names](https://gist.github.com/kmill/b72bb43f5b01dafef41eb1d2e57a8237)
and [new generated
names](https://gist.github.com/kmill/393acc82e7a8d67fc7387829f4ed547e).)
Some notes:
* The naming is sensitive to what is explicitly provided as a binder vs
what is provided via a `variable`. It does not make use of `variable`s
since, when names are generated, it is not yet known which variables are
used in the body of the instance.
* If the instance name refers to declarations in the current "project"
(given by the root module), then it does not add a suffix. Otherwise, it
adds the project name as a suffix to protect against cross-project
collisions.
* `set_option trace.Elab.instance.mkInstanceName true` can be used to
see what name the auto-generator would give, even if the instance
already has an explicit name.
There were a number of instances that were referred to explicitly in
meta code, and these have been given explicit names.
Removes the unused `Lean.Elab.mkFreshInstanceName` along with the
Command state's `nextInstIdx`.
Fixes#2343
As a special case, makes the `rcases` machinery use `Nat.casesAuxOn` so
that goal states see `0` and `n + 1` rather than `Nat.zero` and
`Nat.succ n`. This is a followup to enabling custom eliminators for
`cases` and `induction`.
This doesn't use custom eliminators in general since `rcases` uses
`Lean.MVarId.cases`, which is completely different from what `cases` and
`induction` use.
Adds options to control whitespace normalization and message ordering in
`#guard_msgs`.
Examples:
1. `#guard_msgs (whitespace := lax)` ignores differences in whitespace
completely.
2. `#guard_msgs (whitespace := exact)` requires an exact match for
whitespace (after trimming).
3. `#guard_msgs (ordering := sorted)` sorts the list of messages, to
make it insensitive to message order.
