This PR adds rewrites that normalizes left shifts by extracting bits and
concatenating zeroes. If the shift amount is larger than the bit-width,
then the resulting bitvector is zero.
```lean
theorem shiftLeft_eq_zero {x : BitVec w} {n : Nat} (hn : w ≤ n) : x <<< n = 0#w
theorem shiftLeft_eq_concat_of_lt {x : BitVec w} {n : Nat} (hn : n < w) :
x <<< n = ((x.extractLsb' 0 (w-n)).append (BitVec.zero n)).cast (by omega)
```
This PR documents the equality between the `ModuleIdx` of an module and
the index in the array of `moduleNames` of the same module.
I asked about this in the Office hours and it was confirmed that this is
a current feature and one that is likely not to change!
This PR fixes a few bugs in the `grind` tactic: missing issues, bad
error messages, incorrect threshold in the canonicalizer, and bug in the
ground pattern internalizer.
This PR supports rewriting `ushiftRight` in terms of `extractLsb'`. This
is the companion PR to #6743 which adds the similar lemmas about
`shiftLeft`.
```lean
theorem ushiftRight_eq_zero {x : BitVec w} {n : Nat} (hn : w ≤ n) :
x >>> n = 0#w
theorem ushiftRight_eq_extractLsb'_of_lt {x : BitVec w} {n : Nat} (hn : n < w) :
x >>> n = ((0#n) ++ (x.extractLsb' n (w - n))).cast (by omega)
```
This PR adds the lemmas that show what happens when multiplying by
`twoPow` to an arbitrary term, as well to another `twoPow`.
This will be followed up by a PR that uses these to build a simproc to
canonicalize `twoPow w i * x` and `x * twoPow w i`.
This PR ensures that conditional equation theorems for function
definitions are handled correctly in `grind`. We use the same
infrastructure built for `match`-expression equations. Recall that in
both cases, these theorems are conditional when there are overlapping
patterns.
Avoids build time overhead until the option is proven to speed up
average projects. Adds Init.Prelude (many tiny declarations, "worst
case") and Init.List.Sublist (many nontrivial theorems, "best case")
under -DElab.async=true as new benchmarks for tracking.
This PR adds a fast path for bitblasting multiplication with constants
in `bv_decide`.
While the circuit generated is the same (as the AIG already performs
constant folding) this avoids calling out to the shift and addition
bitblaster unless required. Thus the overall time to generate the
circuit is reduced. Inspired by
[bitwuzla](25d77f819c/src/lib/bitblast/bitblaster.h (L454)).
This PR updates our lexical structure documentation to mention the newly
supported ⱼ which lives in a separate unicode block and is thus not
captured by the current ranges.
This PR adds support for `bv_decide` to automatically split up
non-recursive structures that contain information about supported types.
It can be controlled using the new `structures` field in the `bv_decide`
config.
This PR ensures that the branches of an `if-then-else` term are
internalized only after establishing the truth value of the condition.
This change makes its behavior consistent with the `match`-expression
and dependent `if-then-else` behavior in `grind`.
This feature is particularly important for recursive functions defined
by well-founded recursion and `if-then-else`. Without lazy
`if-then-else` branch internalization, the equation theorem for the
recursive function would unfold until reaching the generation depth
threshold, and before performing any case analysis. See new tests for an
example.
This PR adds support for case splitting on `match`-expressions with
overlapping patterns to the `grind` tactic. `grind` can now solve
examples such as:
```
inductive S where
| mk1 (n : Nat)
| mk2 (n : Nat) (s : S)
| mk3 (n : Bool)
| mk4 (s1 s2 : S)
def g (x y : S) :=
match x, y with
| .mk1 a, _ => a + 2
| _, .mk2 1 (.mk4 _ _) => 3
| .mk3 _, .mk4 _ _ => 4
| _, _ => 5
example : g a b > 1 := by
grind [g.eq_def]
```
This PR adds better support for overlapping `match` patterns in `grind`.
`grind` can now solve examples such as
```lean
inductive S where
| mk1 (n : Nat)
| mk2 (n : Nat) (s : S)
| mk3 (n : Bool)
| mk4 (s1 s2 : S)
def f (x y : S) :=
match x, y with
| .mk1 _, _ => 2
| _, .mk2 1 (.mk4 _ _) => 3
| .mk3 _, _ => 4
| _, _ => 5
example : b = .mk2 y1 y2 → y1 = 2 → a = .mk4 y3 y4 → f a b = 5 := by
unfold f
grind (splits := 0)
```
---------
Co-authored-by: Leonardo de Moura <leodemoura@amazon.com>
This PR adds lemmas about HashMap.alter and .modify. These lemmas
describe the interaction of alter and modify with the read methods of
the HashMap. The additions affect the HashMap, the DHashMap and their
respective raw versions. Moreover, the raw versions of alter and modify
are defined.
---------
Co-authored-by: Paul Reichert <6992158+datokrat@users.noreply.github.com>
This PR adds `foo.fun_cases`, an automatically generated theorem that
splits the goal according to the branching structure of `foo`, much like
the Functional Induction Principle, but for all functions (not just
recursive ones), and without providing inductive hypotheses.
The design isn't quite final yet as to which function parameters should
become targets of the motive, and which parameters of the theorem, but
the current version is already proven to be useful, so start with this
and iterate later.
This PR adds the ability to define possibly non-terminating functions
and still be able to reason about them equationally, as long as they are
tail-recursive or monadic.
Typical uses of this feature are
```lean4
def ack : (n m : Nat) → Option Nat
| 0, y => some (y+1)
| x+1, 0 => ack x 1
| x+1, y+1 => do ack x (← ack (x+1) y)
partial_fixpiont
def whileSome (f : α → Option α) (x : α) : α :=
match f x with
| none => x
| some x' => whileSome f x'
partial_fixpiont
def computeLfp {α : Type u} [DecidableEq α] (f : α → α) (x : α) : α :=
let next := f x
if x ≠ next then
computeLfp f next
else
x
partial_fixpiont
noncomputable def geom : Distr Nat := do
let head ← coin
if head then
return 0
else
let n ← geom
return (n + 1)
partial_fixpiont
```
This PR contains
* The necessary fragment of domain theory, up to (a variant of)
Knaster–Tarski theorem (merged as
https://github.com/leanprover/lean4/pull/6477)
* A tactic to solve monotonicity goals compositionally (a bit like
mathlib’s `fun_prop`) (merged as
https://github.com/leanprover/lean4/pull/6506)
* An attribute to extend that tactic (merged as
https://github.com/leanprover/lean4/pull/6506)
* A “derecursifier” that uses that machinery to define recursive
function, including support for dependent functions and mutual
recursion.
* Fixed-point induction principles (technical, tedious to use)
* For `Option`-valued functions: Partial correctness induction theorems
that hide all the domain theory
This is heavily inspired by [Isabelle’s `partial_function`
command](https://isabelle.in.tum.de/doc/codegen.pdf).
This PR defines `reverse` for bitvectors and implements a first subset
of theorems (`getLsbD_reverse, getMsbD_reverse, reverse_append,
reverse_replicate, reverse_cast, msb_reverse`). We also include some
necessary related theorems (`cons_append, cons_append_append,
append_assoc, replicate_append_self, replicate_succ'`) and deprecate
theorems`replicate_zero_eq` and `replicate_succ_eq`.
---------
Co-authored-by: Alex Keizer <alex@keizer.dev>
Co-authored-by: Kim Morrison <kim@tqft.net>
This PR changes the identifier parser to allow for the ⱼ unicode
character which was forgotten as it lives by itself in a codeblock with
coptic characters.
This PR deprecates `List.iota`, which we make no essential use of. `iota
n` can be replaced with `(range' 1 n).reverse`. The verification lemmas
for `range'` already have better coverage than those for `iota`.
Any downstream projects using it (I am not aware of any) are encouraged
to adopt it.
This PR modifies LCNF.toMonoType to use a more refined type erasure
scheme, which distinguishes between irrelevant/erased information
(represented by lcErased) and erased type dependencies (represented by
lcAny). This corresponds to the irrelevant/object distinction in the old
code generator.
This PR renames the option `infoview.maxTraceChildren` to
`maxTraceChildren` and applies it to the cmdline driver and language
server clients lacking an info view as well. It also implements the
common idiom of the option value `0` meaning "unlimited".
This PR fixes a bug in the equational theorem generator for
`match`-expressions. See new test for an example.
Signed-off-by: Leonardo de Moura <leodemoura@amazon.com>
Co-authored-by: Leonardo de Moura <leodemoura@amazon.com>
This PR introduces a new feature that allows users to specify which
inductive datatypes the `grind` tactic should perform case splits on.
The configuration option `splitIndPred` is now set to `false` by
default. The attribute `[grind cases]` is used to mark inductive
datatypes and predicates that `grind` may case split on during the
search. Additionally, the attribute `[grind cases eager]` can be used to
mark datatypes and predicates for case splitting both during
pre-processing and the search.
Users can also write `grind [HasType]` or `grind [cases HasType]` to
instruct `grind` to perform case splitting on the inductive predicate
`HasType` in a specific instance. Similarly, `grind [-Or]` can be used
to instruct `grind` not to case split on disjunctions.
Co-authored-by: Leonardo de Moura <leodemoura@amazon.com>
The current text is missing a negative sign on the bottom of the
interval that `Int.bmod` can return. While I'm here, I added
illustrative example outputs to match docs for tdiv/ediv/fdiv/etc.
This PR adds the attributes `[grind cases]` and `[grind cases eager]`
for controlling case splitting in `grind`. They will replace the
`[grind_cases]` and the configuration option `splitIndPred`.
After update stage0, we will push the second part of this PR.
