Fixes#4455, fixes#4705, fixes#5219
Also fixes a minor bug where a dot in brackets would report incorrect
completions instead of no completions.
---------
Co-authored-by: Sebastian Ullrich <sebasti@nullri.ch>
I found that the kernel has special support for `e =?= true`, and will
in this case aggressively whnf `e`. This explains the following behavior
(for a `sqrt` function with fuel):
```lean
theorem foo : sqrt 100000000000000000002 == 10000000000 := rfl -- fast
theorem foo : sqrt 100000000000000000002 = 10000000000 := rfl -- slow
theorem foo : sqrt 100000000000000000002 = 10000000000 := by decide -- fast
```
The special support in the kernel only applies for closed `e` and `true`
on the RHS. It could be generlized (also open terms, also `false`, other
data type's constructors, different orientation). But maybe I should
wait for evidence that this generaziation really matters, or whether
all applications (proof by reflection) can be made to have this form.
This PR enables the use of incrementality for completion in tactic
blocks. Consider the following example:
```lean
example : True := by
have : True := T
sleep 10000
```
Before this PR, in order to respond to a completion request after `T`,
`sleep 10000` has to complete first since the command must be fully
elaborated. After this PR, the completion request is responded to
immediately.
Currently, `ll_infer_type` is responsible for telling the user about
`noncomputable` when a definition depends on one without executable
code. However, this is imperfect because type inference does not check
every subexpression. This leads to errors later on that users find to be
hard to interpret.
Now, `Lean.IR.checkDecls` has a friendlier error message when it
encounters constants without compiled definitions, suggesting to
consider using `noncomputable`. While this function is an internal IR
consistency check, it is also reasonable to have it give an informative
error message in this particular case. The suggestion to use
`noncomputable` is limited to just unknown constants.
Some alternatives would be to either (1) create another checker just for
missing constants, (2) change `ll_infer_type` to always visit every
subexpression no matter if they are necessary for inferring the type, or
(3) investigate whether `tests/lean/run/1785.lean` is due to a deeper
issue.
Closes#1785
This is "upstreaming" mathlib's `unfold_let` tactic by incorporating its
functionality into `unfold`. Now `unfold` can, in addition to unfolding
global definitions, unfold local definitions. The PR also updates the
`conv` version of the tactic.
An improvement over `unfold_let` is that it beta reduces unfolded local
functions.
Two features not present in `unfold` are that (1) `unfold_let` with no
arguments does zeta delta reduction of *all* local definitions, and also
(2) `unfold_let` can interleave unfoldings (in contrast, `unfold a b c`
is exactly the same as `unfold a; unfold b; unfold c`).
Closes RFC #4090
When an eliminator was overapplied with more than one additional
argument, elaboration produced an incorrect term because the list of
processed arguments was being reversed. Now these arguments are not
reversed.
1. Remove the need to allocate an intermediate `String` for literally
every character in a JSON `String`.
2. Use a single `String` buffer in the entire `Json.compress` machinery.
3. Use `toListAppend`
Number 1 is doing most of the lifting in the perf diff, the rest are
some minor but measurable improvements.
We change the `bv_decide` to understand `BitVec.extractLsb'` as a
primitive, and add a normalization lemma for `extractLsb`.
It's important to pick the primed version as a primitive, because it is
not always possible to rewrite `extractLsb'` back into `extractLsb` (see
#5007 for that direction, and the relevant side-conditions).
That is, with this PR, `bv_decide` is able to bitblast both versions of
extracting bits.
I don't think we gain anything from having them as `abbrev` here, and
the simpNF linter complains:
```
-- Init.Data.BitVec.Lemmas
#check @BitVec.toNat_intMin /- simp can prove this:
by simp only [BitVec.toNat_twoPow]
One of the lemmas above could be a duplicate.
If that's not the case try reordering lemmas or adding @[priority].
-/
#check @BitVec.toNat_intMax /- Left-hand side simplifies from
(BitVec.intMax w).toNat
to
(2 ^ w - 1 % 2 ^ w + 2 ^ (w - 1)) % 2 ^ w
using
simp only [@BitVec.toNat_sub, @BitVec.ofNat_eq_ofNat, BitVec.toNat_ofNat, BitVec.toNat_twoPow, Nat.add_mod_mod]
Try to change the left-hand side to the simplified term!
-/
```
```
#lint only simpNF in all
```
reports (amongst others):
```
-- Init.Data.Int.Order
#check @Int.toNat_of_nonneg /- Left-hand side simplifies from
↑a.toNat
to
max a 0
using
simp only [Int.ofNat_toNat]
Try to change the left-hand side to the simplified term!
-/
#check Int.toNat_sub_toNat_neg /- Left-hand side simplifies from
↑n.toNat - ↑(-n).toNat
to
max n 0 - max (-n) 0
using
simp only [Int.ofNat_toNat]
Try to change the left-hand side to the simplified term!
-/
```
This doesn't completely resolve the danger (only relevant in `prelude`
files) of importing `Init.Data.List.Basic` but not `Init.Data.List.Impl`
and thereby not having `@[csimp]` lemmas installed for some list
operations.
I'm going to address this better while working on `Array`.
Sebastian mentioned that the use of the kernel defeq was to work around
a performance issue that was fixed since. Let's see if we can do
without.
This is also a semantic change: Ground terms (no free vars, no mvars)
are reduced at
“all” transparency even if the the transparency setting is default. This
was the case
even before 03f6b87647 switched to the
kernel defeq
checking for performance. It seems that this is rather surprising
behavior from the user
point of view. The fallout on batteries and mathlib is rather limited,
only a few
`rfl` proofs seem to have (inadvertently or not) have relied on this.
The speedcenter reports no significant regressions on core or mathlib.
