Declarations with `@[elab_as_elim]` could elaborate as type-incorrect
expressions. Reported by Jireh Loreaux [on
Zulip](https://leanprover.zulipchat.com/#narrow/stream/287929-mathlib4/topic/bug.20in.20revert/near/450522157).
(In principle the elabAsElim routine could revert fvars appearing in the
expected type that depend on the discriminants (if the discriminants are
fvars) to increase the likelihood of type correctness, but that's at the
cost of some complexity to both the elaborator and to the user.)
Now it suggests using `@[ext (iff := false)]` to disable generating the
`ext_iff` lemma.
This PR also adjusts error messages and attribute documentation.
Additionally, to simplify the code now the `x` and `y` arguments can't
come in reverse order (this feature was was added in the refactor
#4543).
Closes#4758
A more restrictive but efficient max sharing primitive.
**Motivation:** Some software verification proofs may contain
significant redundancy that can be eliminated using hash-consing (also
known as `shareCommon`). For example, [theorem
`sha512_block_armv8_test_4_sym`](460fe5d74c/Proofs/SHA512/SHA512Sym.lean (L29))
took a few seconds at [`addPreDefinitions`
](1a12f63f74/src/Lean/Elab/PreDefinition/Main.lean (L155))
and one second at `fixLevelParams` on a MacBook Pro (with M1 Pro). The
proof term initially had over 16 million subterms, but the redundancy
was indirectly and inefficiently eliminated using `Core.transform` at
`addPreDefinitions`. I tried to use `shareCommon` method to fix the
performance issue, but it was too inefficient. This PR introduces a new
`shareCommon'` method that, although less flexible (e.g., it uses only a
local cache and hash-consing table), is much more efficient. The new
procedure minimizes the number of RC operations and optimizes the
caching strategy. It is 20 times faster than the old `shareCommon`
procedure for theorem `sha512_block_armv8_test_4_sym`.
I noticed that a change to `Lean.PrettyPrinter.Delaborator.Builtins`
rebuilt more modules than I expected, so I moved a definition and
reduced some dependcies.
More reduction would be possible to move const-delaboration out of the
big `Lean.PrettyPrinter`, and import from `Lean.PrettyPrinter`
selectively.
Add helper function for computing the number of allocated
sub-expressions in a given expression. Note: Use this function primarily
for diagnosing performance issues.
This PR addresses the absence of the `profileitM` function in two
auxiliary functions. The added `profileitM` instances are particularly
useful for diagnosing performance issues in declarations that contain
many repeated sub-terms.
The name `remove` was chosen because it is more popular in mainstream
programming languages, but being consistent with other Lean container
types (including `Lean.HashMap` and `Batteries.HashMap`) is more
important, so let's change the name while we still can.
the internal constructions for structural and well-founded recursion
use plenty of `PProd` and `MProd`, and reading these, deeply
nested and in prefix notation, is unnecessarily troublesome.
Therefore this introduces notations
```
a ×ₚ b -- PProd a b
a ×ₘ b -- MProd a b
()ₚ -- PUnit.unit
(x,y,z)ₚ -- PProd.mk x (PProd.mk y z)
(x,y,z)ₘ -- MProd.mk x (MProd.mk y z)
```
(This is the post-stage0-part 2.)
the internal constructions for structural and well-founded recursion
use plenty of `PProd` and `MProd`, and reading these, deeply
nested and in prefix notation, is unnecessarily troublesome.
Therefore this introduces notations
```
a ×ₚ b -- PProd a b
a ×ₘ b -- MProd a b
()ₚ -- PUnit.unit
(x,y,z)ₚ -- PProd.mk x (PProd.mk y z)
(x,y,z)ₘ -- MProd.mk x (MProd.mk y z)
```
(This is part 1, the rest will follow in #4730 after a stage0 update.)
This now works:
```lean
inductive Tree where | node : List Tree → Tree
mutual
def Tree.size : Tree → Nat
| node ts => list_size ts
def Tree.list_size : List Tree → Nat
| [] => 0
| t::ts => t.size + list_size ts
end
```
It is still out of scope to expect to be able to use nested recursion
(e.g. through `List.map` or `List.foldl`) here.
Depends on #4718.
---------
Co-authored-by: Tobias Grosser <tobias@grosser.es>
the support for mutual structural recursion (new since #4575) is
extended so that Lean tries to infer it even without annotations.
* The error message when termination checking fails looks quite
different now. Maybe a bit better, maybe with more room for
improvements.
* If there are too many combinations (with an arbitrary cut-off) for a
given argument type, it will just give up and ask the user to use
`termination_by structural`.
* It is now legal to specify `termination_by structural` on not
necessarily all functions of a clique; this simply restricts the
combinations of arguments that Lean considers.
---------
Co-authored-by: Tobias Grosser <tobias@grosser.es>
This adds the types
* `IndGroupInfo`, a variant of `InductiveVal` with information that
applies to a whole group of mutual inductives and
* `IndGroupInst` which extends `IndGroupInfo` with levels and parameters
to indicate a instantiation of the group.
One purpose of this abstraction is to make it clear when a fuction
operates on a group as a whole, rather than a specific inductive within
the group.
This is extracted from #4718 and #4733 to reduce PR size and improve
bisectability.
Improves a number of elements related to Git checkouts, cloud releases,
and related error handling.
* On error, Lake now prints all top-level logs. Top-level logs are those
produced by Lake outside of the job monitor (e.g., when cloning
dependencies).
* When fetching a remote for a dependency, Lake now forcibly fetches
tags. This prevents potential errors caused by a repository recreating
tags already fetched.
* Tweaked Git error handling to hopefully be more informative.
* The builtin package facets `release`, `optRelease`, `extraDep` are now
caption in the same manner as other facets. Previously, they were
attempting to be too clever.
* `afterReleaseSync` and `afterReleaseAsync` now fetch `optRelease`
rather than `release`.
* Added support for optional jobs, whose failure does not cause the
whole build to failure (and made `optRelease` such a job).
Closes#4302.
We now get `.below` and `.brecOn` definitions for nested inductives.
No surprises in the implementation: the kernel already gives us suitable
`.rec_1` etc. recursors, and our construction follows the structure of
this recursor.
---------
Co-authored-by: Tobias Grosser <tobias@grosser.es>
Adds a command and tactic to print the `Array <| DiscrTree.Key` for
equalities helping the user to debug perceived `simp` failures.
---------
Co-authored-by: Joachim Breitner <mail@joachim-breitner.de>
this idiom shows up multiple times, is non-trivial (in the sense that
the `localInsts` has to be updated, and I am about to use it once more.
Hence time to abstract this out.
When the `decide` tactic fails, it can try to give hints about the
failure:
- It tells you which `Decidable` instances it unfolded, by making use of
the diagnostics feature.
- If it encounters `Eq.rec`, it gives you a hint that one of these
instances was likely defined using tactics.
- If it encounters `Classical.choice`, it hints that you might have
classical instances in scope.
- During this, it tries to process `Decidable.rec`s and matchers to pin
blame on a particular instance that failed to reduce.
This idea comes from discussion with Heather Macbeth [on
Zulip](https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/Decidable.20with.20structures/near/449409870).
this code
```
inductive N where
| cons : (Nat -> N) -> N
mutual
def f : N -> Nat
| .cons a => g (a 32) + 1
termination_by structural n => n
def g : N -> Nat
| .cons a => f (a 42) + 1
termination_by structural n => n
end
```
would break. When searching for the right `belowDict` we now have to,
evne after instantiating the paramters for a reflexive argument, again
search through a bunch of `PProd`s.
(Instead of searching we could pass down the index, but since we are
searching anyways in this function let's just re-use.)
Fixes: #4726
Matchers usually have implicit arguments, and even if they don't the
notation hides the name of the matcher function.
Now when hovering over `match` expressions you can see the actual
underlying matcher expression.
if will fail otherwise, but with a worse error message, and it's helpful
in later transformation to know that the parameters are the same for the
whole group.
Upstreaming of basic material on `List.Pairwise` and `List.Nodup`. More
complete API to follow later, this is just a first approximation of what
leansat will need.
When a definition is redeclared, the original code would clobber the
value of `const2ModIdx` every time, meaning that a constant would be
attributed to a module which occurs later than the modules for constants
referencing this one. Preferring the original module ensures that these
module indexes are dependency-ordered. This originally came up as a bug
in `shake`, which assumes this property, see
[Zulip](https://leanprover.zulipchat.com/#narrow/stream/287929-mathlib4/topic/check.20for.20unused.20imports.20doesn't.20stop/near/449139309).
