This PR changes the behaviour of `apply?` so that the `sorry` it uses to
close the goal is non-synthetic. (Recall that correct use of synthetic
sorries requires that the tactic also generates an error message, which
we don't want to do in this situation.) Either this PR or #8230 are
sufficient to defend against the problem reported in #8212.
This PR prevents `exact?` and `apply?` from suggesting tactics that
correspond to correct proofs but do not elaborate, and it allows these
tactics to suggest `expose_names` when needed.
These tactics now indicate that a non-compiling term was generated but
do not suggest that that term be inserted. `exact?` also no longer
suggests that the user try `apply?` if no partial suggestions were
found.
This addresses part of #5407 but does not achieve the exact expected
behavior therein (due to #6122).
#3850 included a commit that added an extra test for `exact?`, but was
otherwise unrelated the to PR. It also removed a test. I've
cherry-picked that test over, and restored the deleted test, and next
will remove the commit from #3850.
`Nat.succ_eq_add_one` and `Nat.pred_eq_sub_one` are now simp lemmas. For
theorems about `Nat.succ` or `Nat.pred` without corresponding theorem
for `+ 1` or `- 1`, this adds the corresponding theorem.
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>
The matches returned by the lazy discriminator tree are partially
constrained by a priority, but ties are broken by the order in which
keys are traversed and the order of declarations.
This PR changes the match key traversal to use an explicit stack rather
than recursion and implicitly changes the order in which results are
returned to favor left-matches first e.g., given the term `f a b` with
constants `f a b`, and a tree with patterns `f a x -> 1` `f x b -> 2`
that have the same priority, this will return `#[1, 2]` since the early
matches for the key `a` are returned before the match for `x` which has
a star.
This appears to address the [lower quality results mentioned on
zulip](https://leanprover.zulipchat.com/#narrow/stream/428973-nightly-testing/topic/Mathlib.20status.20updates/near/429955747).
This makes several changes to rw? and lazy discrimination trees based on
test failures in rewrite search.
Changes include:
1. Reverting to Mathlib function for candidate lemma priority in rw?
2. Introducing additional filters for auto-generated named in lazy
discriminator tree.
3. Refactoring lazy discriminator values to clarify what is stored.
4. Including star keys in calculation of match closeness in
prioritization.
5. Using more fields in current core context when initializing lazy
discriminator tree and avoiding max heartbeat issues.
---------
Co-authored-by: Scott Morrison <scott.morrison@gmail.com>
Sets the default value to `pp.fieldNotation.generalized` to `true`.
Updates tests, and fixes some minor flaws in the implementation of the
generalized field notation pretty printer.
Now generalized field notation won't be used for any function that has a
`motive` argument. This is intended to prevent recursors from pretty
printing using it as (1) recursors are more like control flow structures
than actual functions and (2) generalized field notation tends to cause
elaboration problems for recursors.
Note: be sure functions that have an `@[app_unexpander]` use
`@[pp_nodot]` if applicable. For example, `List.toArray` needs
`@[pp_nodot]` to ensure the unexpander prints it using `#[...]`
notation.
