This PR modifies the syntax of `induction`, `cases`, and other tactics
that use `Lean.Parser.Tactic.inductionAlts`. If a case omits `=> ...`
then it is assumed to be `=> ?_`. Example:
```lean
example (p : Nat × Nat) : p.1 = p.1 := by
cases p with | _ p1 p2
/-
case mk
p1 p2 : Nat
⊢ (p1, p2).fst = (p1, p2).fst
-/
```
This works with multiple cases as well. Example:
```lean
example (n : Nat) : n + 1 = 1 + n := by
induction n with | zero | succ n ih
/-
case zero
⊢ 0 + 1 = 1 + 0
case succ
n : Nat
ih : n + 1 = 1 + n
⊢ n + 1 + 1 = 1 + (n + 1)
-/
```
The `induction n with | zero | succ n ih` is short for `induction n with
| zero | succ n ih => ?_`, which is short for `induction n with | zero
=> ?_ | succ n ih => ?_`. Note that a consequence of parsing is that
only the last alternative can omit `=>`. Any `=>`-free alternatives
before an alternative with `=>` will be a part of that alternative.
Rationale:
- In the future we may require `tacticSeq` to be indented. For
one-constructor types, this lets the rest of the tactic sequence not
need indentation.
- This is a semi-structured alternative to the `cases'`/`induction'`
tactics in mathlib.
This PR ensure that `bv_decide` can handle the simp normal form of a
shift.
Consider:
```lean
theorem test1 (b s : BitVec 5) (hb : b = 0) (hs : s ≠ 0)
: b <<< s = 0 := by
bv_decide
```
This works out, however:
```lean
theorem test2 (b s : BitVec 5) (hb : b = 0) (hs : s ≠ 0)
: b <<< s = 0 := by
simp
bv_decide
```
this fails because the `simp` normal form adds `toNat` to the right hand
argument of the `<<<` and `bv_decide` cannot deal with shifts by
non-constant `Nat`.
Discovered by @spdskatr
This PR fixes a bug in bv_decide where if it was presented with a match
on an enum with as many arms as constructors but the last arm being a
default match it would (wrongly) give up on the match.
This PR modifies `all_goals` so that in recovery mode it commits changes
to the state only for those goals for which the tactic succeeds (while
preserving the new message log state). Before, we were trusting that
failing tactics left things in a reasonable state, but now we roll back
and admit the goal. The changes also fixes a bug where we were rolling
back only the metacontext state and not the tactic state, leading to an
inconsistent state (a goal list with metavariables not in the
metacontext). Closes#7883
Alternatively we could stop on the first error, however it is helpful to
see what the tactic did to each goal while interactively writing a
tactic script. There is some non-monotonicity here though since tactics
can solve for metavariables that appear in successive goals, and
conceivably a later goal succeeds only if a previous one does. Given
that the non-monotonicity is limited to recovery mode (which is for
example the RHS and not the LHS of the `<;>` combinator), we think this
is acceptable.
Another justification for the change to roll back the state on each
failure is that we need to admit goals in the failing cases. When a
tactic throws an error, we cannot assume the goal list is meaningful.
Rolling back lets us admit just the goal the tactic started with,
without needing to try to work out which new metavariables should be
admitted in the error state, allowing the tactic to continue trying the
tactic on the next goal.
This PR adds the attribute `[grind ext]`. It is used to select which
`[ext]` theorems should be used by `grind`. The option `grind +extAll`
instructs `grind` to use all `[ext]` theorems available in the
environment.
After update stage0, we need to add the builtin `[grind ext]`
annotations to key theorems such as `funext`.
This PR extends `Std.Channel` to provide a full sync and async API, as
well as unbounded, zero sized and bounded channels.
A few notes on the implementation:
- the bounded channel is inspired by [Go channels on
steroids](https://docs.google.com/document/d/1yIAYmbvL3JxOKOjuCyon7JhW4cSv1wy5hC0ApeGMV9s/pub)
though currently doesn't do any of the lock-free optimizations
- @mhuisi convinced me that having a non-closable channel may be a good
idea as this alleviates the need for error handling which is very
annoying when working with `Task`. This does complicate the API a little
bit and I'm not quite sure whether this is a choice we want users to
give. An alternative to this would be to just write `send!` that panics
on sending to a closed channel (receiving from a closed channel is not
an error), this is for example the behavior that golang goes with.
This PR fixes two issues that were preventing `grind` to solve
`getElem?_eq_some_iff`.
1. Missing propagation rule for `Exists p = False`
2. Missing conditions at `isCongrToPrevSplit` a filter for discarding
unnecessary case-splits.
This PR fixes an issue introduced bug #6125 where an `inductive` or
`structure` with an autoimplicit parameter with a type that has a
metavariable would lead to a panic. Closes#7788.
This was due to switching from `Term.addAutoBoundImplicits'` to
`Term.addAutoBoundImplicits` and not properly handling metavariables in
the parameters list. To fix this, now the inductive type headers record
the abstracted type and the number of parameters, rather than record the
parameters, the type, the local context, and the local instances. A
benefit to this over `Term.addAutoBoundImplicits'` is that the type's
parameters do not appear twice in the local context.
This PR fixes two bugs in `grind`.
1. Model-based theory combination was creating type incorrect terms.
2. `Nat.cast` vs `NatCast.natCast` issue during normalization.
This PR fixes an issue where `let n : Nat := sorry` in the Infoview
pretty prints as ``n : ℕ := sorry `«Foo:17:17»``. This was caused by
top-level expressions being pretty printed with the same rules as
Infoview hovers. Closes#6715. Refactors `Lean.Widget.ppExprTagged`; now
it takes a delaborator, and downstream users should configure their own
pretty printer option overrides if necessary if they used the `explicit`
argument (see `Lean.Widget.makePopup.ppExprForPopup` for an example).
Breaking change: `ppExprTagged` does not set `pp.proofs` on the root
expression.
This PR cleans up the `Option` development, upstreaming some results
from mathlib in the process.
Notable changes:
- the name `<op>_eq_some_iff` is preferred over `<op>_eq_some`
- the `simp` normal form for `<$>` is `Option.map`, for `>>=` is
`Option.bind` and for `<|>` is `Option.orElse` (for the former two, this
was already true before this PR). All further lemmas about these
operations are now stated only in terms of
`Option.map`/`Option.bind`/`Option.orElse`. Previously, in some cases
both versions were available, with a prime used to disambiguate (the
primed version was usually the "non-ascii-art" version). Now, there are
no lemmas about the ascii-art versions besides the ones turning them
into the non-ascii-art operations, and there is only one version of
every lemma, about the non-ascii-art operation, and named without a
prime.
This PR adds a mixin typeclass for `Lean.Grind.CommRing` recording the
characteristic of the ring, and constructs instances for `Int`, `IntX`,
`UIntX`, and `BitVec`.
This PR eliminates another source of facts of the form `-1 *
NatCast.natCast x <= 0` for each `x : Nat` in the local context. These
facts are now stored internally in the cutsat state.
cc @kim-em
This PR improves the normalization of `Bool` terms in `grind`. Recall
that `grind` currently does not case split on Boolean terms to reduce
the size of the search space.
This PR updates `rw?`, `show_term`, and other tactic-suggesting tactics
to suggest `expose_names` when necessary and validate tactics prior to
suggesting them, as `exact?` already did, and it also ensures all such
tactics produce hover info in the messages showing tactic suggestions.
This introduces a breaking change in the `TryThis` API: the `type?`
parameter of `addRewriteSuggestion` is now an `LOption`, not an
`Option`, to obviate the need for a hack we previously used to indicate
that a rewrite closed the goal.
Closes#7350
This PR fixes an issue where uses of 'noncomputable' definitions can get
incorrectly compiled, while also removing the use of 'noncomputable'
definitions altogether. Some uses of 'noncomputable' definitions (e.g.
Classical.propDecidable) do not get compiled correctly by type erasure.
Running the optimizer on the result can lead to them being optimized
away, eluding the later IR-level check for uses of noncomputable
definitions.
To fix this, we add a 'noncomputable' check earlier in the
erase_irrelevant pass.
This PR adds extensibility to the `evalAndSuggest` procedure used to
implement `try?`. Users can now implement their own handlers for any
tactic. The new test demonstrates how this feature works.
This PR fixes an issue in the cutsat counterexamples. It removes the
optimization (`Cutsat.State.terms`) that was used to avoid the new
theorem `eq_def`. In the two new tests, prior to this PR, `cutsat`
produced a bogus counterexample with `b := 2`.
This PR prevents redundant invocations to `markAsCutsatTerm` which would
trigger equalities of the form `x = x` being propagated. This redundancy
only affected performance and "polluted" trace messages with redundant
information.
This PR improves support for `Nat` in the `cutsat` procedure used in
`grind`:
- `cutsat` no longer *pollutes* the local context with facts of the form
`-1 * NatCast.natCast x <= 0` for each `x : Nat`. These facts are now
stored internally in the `cutsat` state.
- A single context is now used for all `Nat` terms.
The PR also introduces a mapping mechanism for all "foreign" types that
can be converted to `Int`. Currently, only `Nat` is supported, but
additional types will be added in the future.
This PR fixes an issue where `x.f.g` wouldn't work but `(x.f).g` would
when `x.f` is generalized field notation. The problem was that `x.f.g`
would assume `x : T` should be the first explicit argument to `T.f`. Now
it uses consistent argument insertion rules. Closes#6400.
This also improves the algorithm for finding a relevant argument. Before
it would try looking at the type and the whnf of the type, but now it
iteratively unfolds types, checking each intermediate expansion.
This PR modifies the pretty printing of pi types. Now `∀` will be
preferred over `→` for propositions if the domain is not a proposition.
For example, `∀ (n : Nat), True` pretty prints as `∀ (n : Nat), True`
rather than as `Nat → True`. There is also now an option `pp.foralls`
(default true) that when false disables using `∀` at all, for
pedagogical purposes. This PR also adjusts instance implicit binder
pretty printing — nondependent pi types won't show the instance binder
name. Closes#1834.
The linked RFC also suggests using `_` for binder names in case of
non-dependance. We're tabling that idea. Potentially it is useful for
hygienic names; this could improve how `Nat → True` pretty prints as `∀
(a : Nat), True`, with this `a` that's chosen by implication notation
elaboration. Relatedly, this PR exposes even further the issue where
binder names are reused in a confusing way. Consider: `Nat → Nat → (a :
Nat) → a = a` pretty prints as `∀ (a a a : Nat), a = a`.
This PR modifies the pretty printing of raw natural number literals; now
both `pp.explicit` and `pp.natLit` enable the `nat_lit` prefix. An
effect of this is that the hover on such a literal in the Infoview has
the `nat_lit` prefix.
Amendment to RFC #3021: In the reference-level explanation, now it
should read
> When `pp.natLit` and `pp.explicit` are false, then the `nat_lit n`
expression delaborates as `n`, and otherwise it delaborates as `nat_lit
n`.
This PR adds SMT-LIB operators to detect overflow
`BitVec.(umul_overflow, smul_overflow)`, according to the definitions
[here](https://github.com/SMT-LIB/SMT-LIB-2/blob/2.7/Theories/FixedSizeBitVectors.smt2),
and the theorems proving equivalence of such definitions with the
`BitVec` library functions (`umulOverflow_eq`, `smulOverflow_eq`).
Support theorems for these proofs are `BitVec.toInt_one_of_lt,
BitVec.toInt_mul_toInt_lt, BitVec.le_toInt_mul_toInt,
BitVec.toNat_mul_toNat_lt, BitVec.two_pow_le_toInt_mul_toInt_iff,
BitVec.toInt_mul_toInt_lt_neg_two_pow_iff` and `Int.neg_mul_le_mul,
Int.bmod_eq_self_of_le_mul_two, Int.mul_le_mul_of_natAbs_le,
Int.mul_le_mul_of_le_of_le_of_nonneg_of_nonpos, Int.pow_lt_pow`. The PR
also includes a set of tests.
Co-authored by @tobiasgrosser.
---------
Co-authored-by: Tobias Grosser <tobias@grosser.es>
Co-authored-by: Tobias Grosser <github@grosser.es>
Co-authored-by: Siddharth <siddu.druid@gmail.com>
This PR adds a shared mutex (or read-write lock) as `Std.SharedMutex`.
In order to easily migrate a `Std.Mutex` to `Std.SharedMutex` if
necessary, the functions for obtaining exclusive access are named the
same, allowing a correct drop in to be done by just swapping types.
