3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2026-08-02 12:13:25 +00:00
Commit graph

4691 commits

Author SHA1 Message Date
Nikolaj Bjorner
318738b309 Fix #9063: avoid leaking internal seq skolem terms into models
When building the model value of a sequence, an unresolved element such as
(seq.nth_i k!0 0) over an internal sequence constant could be emitted
verbatim, exposing internal skolem symbols (e.g. k!0) in the user-visible
model returned by get-model / get-value.

Such a term is not a proper value and is unconstrained at model-construction
time, so replace it with a concrete fresh value from the sequence factory.
This only affects model values that were already non-concrete (i.e. leaking
internal terms); genuine concrete sequence values satisfy m.is_value and are
left untouched, so sat/unsat verdicts and normal string/sequence models are
unaffected.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 57b9b87e-950a-49ea-bbb3-ed585646a5a9
2026-07-28 10:58:04 -07:00
Copilot
d652bd3fc6
Fix set.size soundness: cardinality lower bound for concrete distinct members (#10246)
`set.size` reported `sat` for `(= 1 (set.size (set.union (set.singleton
1) (set.singleton 2))))` — a soundness bug, not just a performance gap.
The returned model did not satisfy the constraint.

## Root cause

In `theory_finite_set_size::run_solver()`, the cardinality sub-solver
enumerates propositional models of the membership structure and sums
fresh "slack" variables to represent `set.size`. All slacks were bounded
only by `>= 0`, so the arithmetic solver could freely assign `size = 1`
even when two distinct concrete members were independently asserted:

- **Model M₁** (`{1}` active, `{2}` inactive) — element 1 is a concrete
witness → slack must be `≥ 1`
- **Model M₂** (`{1}` inactive, `{2}` active) — element 2 is a concrete
witness → slack must be `≥ 1`

Without this enforcement: `slack₁ = 1, slack₂ = 0` satisfied `size = 1`.
With it: `size ≥ 2`.

## Changes

- **`src/smt/theory_finite_set_size.cpp`** — In `run_solver()`, after
retrieving the propositional model, check if exactly one singleton
equivalence class is active *and* a positive `set.in` assertion exists
for that element in an active set. If so, assert `slack >= 1` instead of
`>= 0`. This is sound: the concrete member witnesses the slot contains
at least one element.

- **`src/ast/rewriter/finite_set_axioms.cpp`** — Add the missing
monotonicity lower bounds for union:
  ```
  |A ∪ B| ≥ |A|    and    |A ∪ B| ≥ |B|
  ```
These complement the existing upper bound `|A ∪ B| ≤ |A| + |B|` and let
the arithmetic solver derive `|{1} ∪ {2}| ≥ 2` directly from the
singleton axiom `|{i}| = 1`.

## Verified cases

| Query | Before | After |
|---|---|---|
| `(= 1 (set.size (set.union (set.singleton 1) (set.singleton 2))))` |
`sat`  | `unsat` ✓ |
| `(= 2 (set.size (set.union (set.singleton 1) (set.singleton 2))))` |
`sat` ✓ | `sat` ✓ |
| `set.in 1 s ∧ set.in 2 s ∧ (= 1 (set.size s))` | `sat`  | `unsat` ✓ |
| `¬(>= (set.size (set.union ...)) 2)` | `sat`  | `unsat` ✓ |

<!-- START COPILOT CODING AGENT SUFFIX -->

- Fixes #10232

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Nikolaj Bjorner <nikolaj@cs.stanford.edu>
2026-07-27 15:05:49 -07:00
Nikolaj Bjorner
538d419978
Update theory_lra.cpp 2026-07-24 14:10:06 -07:00
Nikolaj Bjorner
d60d6a0665 add incremental propagate for nla to retain some propagation lemmas 2026-07-23 19:50:54 -07:00
Nikolaj Bjorner
e3cc338fc9 nla: restore eager propagate_nla during theory_lra propagation
PR #10180 moved nonlinear bound propagation to final_check only, removing
the eager propagate_nla() from the search-time propagation path. This left
E-matching without nla-implied bound facts during search, causing an
instantiation blowup on number-theory goals (e.g. FStar.Math.Euclid),
which exhausted rlimit and returned unknown on queries previously proved.

Re-run propagate_nla() before propagate_bounds_with_lp_solver() in the
l_true case of propagate_core so tightened nonlinear bounds are surfaced
to the SMT core during search. Recovers FStar.Math.Euclid-1/-2.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 96a14756-2ffe-4cc3-87e7-49fda1b6113a
2026-07-23 16:20:44 -07:00
Copilot
a3c7dc9433
fix: smtlib2_compliant mode turns unsat to unknown due to Int/Real sort mismatch in coeffs2app (#10204)
With `(set-option :smtlib2_compliant true)`, Z3 disables implicit
Int→Real coercions. When the LP solver generates Gomory cuts/bounds over
expressions that mix Int and Real LP variables (as happens when
`to_real(n)` is internalized — both `to_real(n)` as Real and `n` as Int
are registered as LP vars), `coeffs2app` was constructing
`mk_mul(Real_numeral, Int_expr)`. Without implicit coercions,
`check_args` throws an `ast_exception` that bubbles up through
`cmd_context::check_sat()` as `l_undef`, producing a spurious `unknown`
instead of `unsat`.

## Changes

- **`src/smt/theory_lra.cpp` — `coeffs2app`**: Before building each
product term, coerce `o` to Real via `a.mk_to_real(o)` when `!is_int &&
a.is_int(o)`. This makes the sort explicit rather than relying on
implicit coercions.

- **`src/test/smt2print_parse.cpp`**: Regression test for the exact
formula from the issue — verifies the result is `unsat` (not `unknown`)
when `smtlib2_compliant` is set.

```smt2
(set-option :smtlib2_compliant true)
(set-logic ALL)
(declare-datatype SBVRational ((SBV.Rational (sbv.rat.numerator Int) (sbv.rat.denominator Int))))
; ... mixed Int/Real via to_real ...
(check-sat)
; was: unknown  (:reason-unknown "Sort mismatch at argument #2 for function * (Real Real) Real supplied sort is Int")
; now: unsat
```

<!-- START COPILOT CODING AGENT SUFFIX -->

- Fixes #10166

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
2026-07-23 12:34:46 -07:00
Nikolaj Bjorner
aba41d026f
nla: add LP-based nonlinear bound optimization for cross-nested confl… (#10180)
…icts

Add core::optimize_nl_bounds() (gated by arith.nl.optimize_bounds) which
runs LP max/min over monomial leaf variables inside core::propagate(),
analogous to solver=2's max_min_nl_vars, so nla (arith.solver=6) can
detect cross-nested conflicts previously missed. Collect improved bounds
first, then apply them and re-establish feasibility once; reconcile the
core solver via find_feasible_solution before the raw maximize solves to
preserve inf_heap_is_correct(). Skip null witnesses in
get_dependencies_of_maximum for implied/unconditional bounds.

On FStar-UInt128-divergence solver=6 this yields unsat in 2
final-checks, seed-insensitive (seeds 1-10).


Copilot-Session: ac36bb84-de91-4e6c-86df-6008c7396ceb

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: ac36bb84-de91-4e6c-86df-6008c7396ceb
Copilot-Session: 96a14756-2ffe-4cc3-87e7-49fda1b6113a
2026-07-23 09:00:46 -07:00
davedets
35b0b42d2e
Use macros to disable semi-colon warnings for blocks of macros. (#10192)
This is another PR towards the goal of getting Z3 to compile cleanly
when included via FetchContents into clang-tidy, which uses a pretty
strict set of warnings.

This PR completes the job started by
https://github.com/Z3Prover/z3/pull/10169. It adds `-Wextra-semi` to the
set of CLANG_ONLY_WARNINGS, and adds
```
START_DISABLE_EXTRA_SEMI_WARNING;
...macro invocations with trailing semis...
END_DISABLE_WARNING;
```
around all the blocks of macro invocations that provoked warnings.

(Additionally, in realclosure.h, there was one block of macro
invocations that did *not* follow the trailing-semi pattern; changed
that to look like all the others).
2026-07-22 18:01:50 -07:00
Copilot
63730fefaf
Fix swapped assert_expr arguments in smt_solver::translate for named assertions (#10135)
With `parallel.enable=true`, Z3 could return a SAT model for a QF_BV
instance that violates its own assertions. The bug traces to solver
translation: named assertions were re-registered with swapped
formula/indicator arguments, corrupting the translated solver's
assertion state.

## Bug

`m_name2assertion` stores `indicator → formula`. In
`smt_solver::translate()`, the structured binding `[k, v]` gives `k =
indicator`, `v = formula`, but `assert_expr(t, a)` expects `(formula,
indicator)`:

```cpp
// Before — args reversed
for (auto& [k, v] : m_name2assertion) {
    expr* val = translator(k);  // indicator
    expr* key = translator(v);  // formula
    result->assert_expr(val, key);  // assert_expr(indicator, formula) ← wrong
}
```

## Fix

```cpp
// After — correct order
for (auto& [k, v] : m_name2assertion) {
    expr* fml = translator(v);  // formula
    expr* ind = translator(k);  // indicator
    result->assert_expr(fml, ind);  // assert_expr(formula, indicator) ✓
}
```

This affects any code path that calls `smt_solver::translate()` and uses
named assertions (`assert_and_track` / `Z3_solver_assert_and_track`),
including all parallel solving modes.

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
2026-07-16 13:46:19 -07:00
Nikolaj Bjorner
2a3b64a7f9 fix #10137
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-16 13:44:38 -07:00
Nikolaj Bjorner
ca2ed44951 disable instantiation for inconsistent states
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-15 20:55:11 -07:00
Nikolaj Bjorner
09ffec52e8 disable instantiation for inconsistent states
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-15 20:54:23 -07:00
Nikolaj Bjorner
9fb2b491d6 remove relvancy marking code
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-15 15:17:14 -07:00
Nikolaj Bjorner
661bb13039 change relevancy marking to top-level on inconsistent states
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-15 11:29:20 -07:00
Nikolaj Bjorner
ad063580dc theory_lra: eagerly propagate offset equalities x=y (fixes #10065)
When a term column x - y is fixed to 0 (e.g. from t <= ca and t >= ca),
theory_lra previously discovered the implied equality x = y only lazily via
assume_eqs() during final_check. On the FP fuel-recursive axiom in issue #10065
this discovery is starved by E-matching, which unfolds the recursion and
bit-blasts an exploding FP subproblem before the branch closes.

Add propagate_offset_eq() to detect a fixed 2-variable offset term with opposite
unit-scaled coefficients and propagate the operand equality x = y directly to the
core, so congruence closure merges dependent terms immediately. This mirrors the
offset-row propagation performed by theory_arith (propagate_cheap_eq) and matches
its behavior on this benchmark (timeout -> unsat 0.06s, 2 quant-instantiations).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 726c4e71-03ff-45f6-8322-5253254e1d7e
2026-07-14 22:46:06 -07:00
Nikolaj Bjorner
7c8c6a4df0 fixup pattern inference 2026-07-14 21:01:15 -07:00
Nikolaj Bjorner
24bde17501 debug array models 2026-07-14 13:52:14 -07:00
Nikolaj Bjorner
2f48e355d8
Add symbolic-modulus congruence rule to nla_divisions (#10119)
Implement check_mod_congruence in nla_divisions: for two mod-atoms
sharing a (possibly symbolic) divisor y, emit the model-guided tautology
div(x,y) - div(s,y) = delta => mod(x,y) - mod(s,y) = (x - s) - delta*y.
This discharges linear congruences over a symbolic modulus that the
nonlinear core did not otherwise isolate. Thread the div(x,y) variable
through add_divisibility (nla_core/nla_solver/nla_divisions) and
register it in theory_lra for symbolic-divisor mod terms.

Solves FStar.BitVector-1 (0.7s) and FStar.Matrix-1 (1.6s), previously
300s timeouts; all 92 unit tests pass.


Copilot-Session: 726c4e71-03ff-45f6-8322-5253254e1d7e

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
2026-07-14 12:31:17 -07:00
Copilot
26ad30bb76
Fix invalid sequence models for seq.foldl results observed through seq.nth (#10111)
`seq.foldl` could produce a concrete sequence model while related
`seq.nth` constraints were still validated against stale or
underconstrained length information, leading to invalid models. In the
reported case, `all` was modeled as `(seq.++ (seq.unit 7) (seq.unit 0))`
while `final = (seq.nth all 0)` remained inconsistent with `final = 6`.

- **Root cause**
- Sequence solutions were propagated as equalities, but parent `seq.len`
terms were not updated when a sequence term was solved.
- As a result, `seq.nth` guard reasoning could miss that a solved
sequence had known in-bounds length.

- **Solver change**
- Extend `theory_seq::add_solution` to collect parent `seq.len`
expressions of a solved term when the solved result is sequence-typed.
- After propagating the solved sequence equality, also propagate the
rewritten length equality for those parent length terms.
- Keep this propagation guarded to sequence results so scalar
`seq.foldl`/`seq.foldli` solutions do not regress from `sat` to
`unknown` under model validation.

- **Regression coverage**
  - Add a focused test for the reported SMT-LIB pattern:
    - `all = seq.foldl(...)`
    - `final = seq.nth all 0`
    - `initial = 0`
    - `final = 6`
- Add focused scalar `seq.foldl`/`seq.foldli` model-validation coverage
for the existing benchmark shapes that must continue returning `sat`.
- The regressions check both that model validation no longer reports an
invalid model for the `seq.nth` case and that scalar fold/foldi cases do
not regress to `unknown`.

- **Effect**
- Solved sequence terms now push enough derived length information for
dependent `seq.nth` constraints to validate against the actual modeled
sequence.
  - Existing scalar fold/foldi solving behavior is preserved.

```smt2
(define-fun all_sums ((prev_sums (Seq Int)) (elem Int)) (Seq Int)
  (seq.++ (seq.unit (+ (seq.nth prev_sums 0) elem)) prev_sums)
)

(assert (= all (seq.foldl all_sums (seq.unit initial) elements)))
(assert (= final (seq.nth all 0)))
(assert (= initial 0))
(assert (= final 6))
```

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
2026-07-13 17:33:39 -07:00
Copilot
710b4082d1
Add constant-bound contradiction shortcut for string < constraints in theory_seq (#10112)
The reported case showed expensive reasoning for lexicographic string
comparisons under the default sequence solver, and incorrect handling
expectations with `z3str3` (which does not interpret these comparisons).
This change targets the default solver path by short-circuiting
contradictory constant-bound `<` constraints earlier.

- **Theory shortcut for constant lexical bounds**
- In `theory_seq::assign_eh`, detect asserted `str.<` constraints of the
form `c < x` or `x < c` where `c` is a string constant.
- When a complementary bound on the same equivalence class is already
true, check bound consistency immediately.
- If bounds are contradictory (`!(lower < upper)`), emit a direct theory
conflict from the two active literals instead of waiting for deeper
axiom propagation.

- **Preserve existing comparison reasoning**
  - Existing `check_lts` transitivity/axiom flow is retained.
- The new logic is a narrow fast path for contradictory constant bounds
and does not alter general string-order semantics.

- **Regression coverage**
- Added a solver-level regression in `src/test/seq_rewriter.cpp` for
contradictory date-like lexical bounds to ensure this class of
constraints is rejected as `unsat`.

```cpp
ctx.assert_expr(su.str.mk_lex_lt(su.str.mk_string("2024-01-01"), x));
ctx.assert_expr(su.str.mk_lex_lt(x, su.str.mk_string("2024-12-31")));
ctx.assert_expr(su.str.mk_lex_lt(x, su.str.mk_string("2023-01-01")));
ENSURE(ctx.check() == l_false);
```

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
2026-07-13 12:56:57 -07:00
Nikolaj Bjorner
7b26fe135a
Add linear divisibility closure lemma for lp/nla solver (#7464) (#10107)
## Summary

Fixes the divergence in issue #7464: formulas involving `mod`/`div` by a
**variable** divisor could send `smt.arith.solver=6` into a
non-terminating nonlinear search.

Minimal reproducer (UNSAT, previously timed out; now solved in <0.5s):

```smt2
(declare-fun V () Int)
(declare-fun n () Int)
(declare-fun l () Int)
(assert (and (> V 0) (= 0 (mod n 2)) (= (div n 2) (div n l)) (= 0 (mod (div n l) V))))
(assert (distinct 0 (mod n V)))
(check-sat)
```

## Root cause

A variable-divisor `mod n V` is axiomatized by the Euclidean identity
`n = V*(n div V) + (n mod V)`. The `V*(n div V)` term is nonlinear, so
arith.solver=6
hands the problem to the nlsat/Gröbner branch, which branches on values
of `V` with no
termination bound and diverges.

## Fix

Add a **linear divisibility closure** lemma in `nla_divisions`:

> `mod(a, y) = 0 & x = c*a` (c an integer constant) ⟹ `mod(x, y) = 0`.

The emitted clause

```
(x - c*a != 0)  \/  (mod(a, y) != 0)  \/  (mod(x, y) = 0)
```

is a **tautology for every integer `c`**, so mining a candidate `c =
val(x)/val(a)` from
the current model can never be unsound. It is only emitted when all
three literals are
false in the current model, so the clause is a genuine
conflict/propagation and always
makes progress. This lets the theory refute the instance directly
instead of entering the
divergent nonlinear branch.

Variable-divisor `mod` terms were previously **not registered** in nla
at all; they are now
registered into a new `m_divisibility` list in `theory_lra`, so the
reasoner can pair a
violated `mod(x, y)` with a satisfied `mod(a, y)` of the same divisor.

## Changes

- `src/math/lp/nla_divisions.{h,cpp}` — new `m_divisibility` list
`{r=mod, x=dividend, y=divisor}`, `add_divisibility(...)`, and
`check_linear_divisibility()`; invoked from `divisions::check()`.
- `src/math/lp/nla_core.h`, `src/math/lp/nla_solver.{h,cpp}` —
forwarding of `add_divisibility`.
- `src/smt/theory_lra.cpp` — register variable-divisor `mod` into the
divisibility list.

## Validation

- `min.smt2` → `unsat` in 0.46s, minimized core → 0.15s (were timeouts).
- Soundness: 350 differential fuzz formulas (arith.solver=6 vs
arith.solver=2), **0 mismatches**.
- Spot checks correct (divisor-3 variant → unsat; non-divisible variants
→ sat).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-07-12 21:20:50 -07:00
Nikolaj Bjorner
606a06fa5f fix warnings
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-12 16:45:24 -07:00
Nikolaj Bjorner
f7afe8e025 tout -> out
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-12 16:41:05 -07:00
Nikolaj Bjorner
bcc176fc47 prepare ground for general projection 2026-07-12 15:59:56 -07:00
Nikolaj Bjorner
eaceded5f1
Issue 438 (#10085)
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
2026-07-12 13:35:57 -07:00
Copilot
efe5e946f1
Fix unsigned overflow in parallel solver conflict budget escalation (#10076)
Z3 4.16.0 introduced a cube-and-conquer parallel solver that regressed
easy QF_LIRA problems from <1s to hanging indefinitely. Workers start
with a 1000-conflict budget and multiply by 1.5× on each timeout, but
after ~38 escalations the `unsigned` cast overflows, causing the budget
to oscillate chaotically (e.g. 3.27B → 618M → 927M → … never reaching a
stable large value). For sub-cubes that require more conflicts than any
value in the oscillation window, the worker loops forever.

## Changes

- **`src/smt/smt_parallel.h`** – `update_max_thread_conflicts()`:
replace raw `(unsigned)(mul * val)` cast with saturating arithmetic that
caps at `UINT_MAX`, eliminating the UB and the oscillation:
  ```cpp
// Before – UB when product > UINT_MAX, budget oscillates after ~38
escalations
  m_config.m_threads_max_conflicts =
(unsigned)(m_config.m_max_conflict_mul *
m_config.m_threads_max_conflicts);

  // After – saturates at UINT_MAX
double next = m_config.m_max_conflict_mul *
m_config.m_threads_max_conflicts;
m_config.m_threads_max_conflicts = (next >= (double)UINT_MAX) ? UINT_MAX
: (unsigned)next;
  ```

- **`src/solver/parallel_tactical.cpp`** – Identical
saturating-arithmetic fix in the `parallel_tactical2` worker's
`update_max_thread_conflicts()`, which is the code path actually
exercised for QF_LIRA problems.

- **`src/smt/smt_parallel.cpp`** – Worker's initial per-cube conflict
budget is now sourced from `m_smt_params.m_threads_max_conflicts` (the
user-visible `smt.threads.max_conflicts` parameter) instead of being
hardcoded to 1000, so users who leave the parameter at its default get
an unlimited initial budget matching Z3 4.12.x portfolio behaviour.

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-10 15:25:57 -07:00
Nikolaj Bjorner
382abb786a disable term enumeration by default
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-10 14:23:40 -07:00
Nikolaj Bjorner
1d425e55cd bug fixes to ho_matching - offset alignment inv_var_shift, callback scopes should not be nested, allow bindings that are not ground
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-09 19:16:12 -07:00
Lev Nachmanson
ed6e2a241d
opt: validate strict optimization optima faithfully with delta-rational bounds (#10059)
## Problem

Maximizing/minimizing under a **strict** inequality has a delta-rational
optimum. For

```smt2
(declare-const r Real)
(assert (< r 1))
(maximize r)
(check-sat)
(get-objectives)
```

the optimum is the supremum `1 - epsilon`, but z3 reported `r = 0`.

The same defect makes shared-symbol objectives report a value matching
**neither the model nor the true optimum** (issue #10028 follow-up).
Minimal reproducer — a 6-mark Golomb ruler (a `>32`-arg `distinct`, so
the objective is coupled to EUF) with a strict real objective `obj >
x5`, whose true optimum is `17 + epsilon`:

| case | before | after |
|---|---|---|
| `maximize r`, `r < 1` | `0`  | `1 - epsilon`  |
| `minimize r`, `r > 1` | `0`  | `1 + epsilon`  |
| Golomb `minimize obj`, `obj > x5` | `35/2` / `7+eps`  | `17 +
epsilon`  |

## Root cause

`check_bound` validates the LP hint by asserting `objective >= optimum`.
For a supremum `1 - epsilon` this is a **lower** bound whose value
carries a **negative** infinitesimal `(1, -1)`.

No `lconstraint_kind` can express that. The kind->infinitesimal map only
yields the *matching-sign* cases — `GT` -> lower `(r, +1)`, `LT` ->
upper `(r, -1)` — or zero (`GE`/`LE`). The opposite-sign lower bound
`(r, -1)` (i.e. `r >= r0 - delta`) is a *relaxation* that no strict
inequality produces. `opt_solver::mk_ge` therefore projected the
`-epsilon` away, turning `r >= 1 - epsilon` into the over-strong,
unsatisfiable `r >= 1`; validation failed and the strictly smaller
current model value was reported instead.

## Fix — carry the infinitesimal faithfully through the bound pipeline

- **`lp_api::bound`** gains an `eps` component so `get_value` returns
the true delta value (no spurious rational fixed-variable equality is
propagated to EUF).
- **`lar_base_constraint`** stores its right-hand side as a
delta-rational `impq` pair; `rhs()` returns the rational component,
`bound_eps()` the infinitesimal one.
- **`lar_solver`** bound activation/update threads the whole `impq`
bound, so a lower bound `(r, -1)` can be asserted. `constraint_holds`
accounts for it using the **same** strict-bounds delta that flattens the
model, computed **once per model**.
- **`theory_lra::mk_ge`** builds a *fresh* predicate for the `(r, -1)`
lower bound (to avoid colliding with an already-internalized `v >= r`
literal) and attaches `eps = -1`. **`opt_solver::mk_ge`** passes the
unprojected value to `theory_lra` / `theory_mi_arith` /
`theory_inf_arith` (whose bounds are already `inf_rational`).

The pair machinery is what makes the supremum both representable
(optimum `1 - epsilon`) and validatable; the reported witness model
remains the flattened rational (`find_delta_for_strict_bounds`),
consistent with the existing epsilon semantics.

## Validation

- Strict optima correct: `1-eps`, `1+eps`, bounded `2<r<5 -> 5-eps`, and
lex/box variants.
- Integer optima and the #10028 shared-symbol cases unchanged (Golomb
n=6/7/8 -> 17/25/34, consistent with the model).
- Unit tests **92/92** (release); no new debug-suite failures.
- Opt regression corpus (73 files, `model_validate=true`)
**byte-identical** to baseline.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-09 10:39:23 -07:00
Nikolaj Bjorner
aa6dddbdf0 update pattern inference to allow patterns with variables outside of scope
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-08 19:48:10 -07:00
Nikolaj Bjorner
30a4a84c79 move verbose out to where it is used 2026-07-08 18:54:03 -07:00
Nikolaj Bjorner
3f6a57e8a8
Improve generation accounting (#10008) (#10009)
Details in original PR: https://github.com/Z3Prover/z3/pull/10007

---------

---------

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
Co-authored-by: Can Cebeci <can.cebeci99@gmail.com>
Co-authored-by: Can Cebeci <t-cancebeci@microsoft.com>
2026-07-08 15:43:41 -07:00
Nikolaj Bjorner
965db51b5c use patterns 2026-07-07 15:00:32 -07:00
Nikolaj Bjorner
7040a74d1a defer ho-matching to lazy mam
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-07 15:00:02 -07:00
Can Cebeci
5fc2b04dea
Mark quantifier instances that lead to conflicts as relevant (#10064)
This patch fixes a corner case where quantifier conflicts can create
fresh terms that aren't marked as relevant.
I couldn't easily produce a minimal query that this patch turns stable,
nor did the patch stabilize the query I have been working on, but I
think the example below still illustrates the problem:

```
(set-option :auto_config false)
(set-option :type_check true)
(set-option :smt.case_split 3)
(set-option :smt.mbqi false)

(declare-fun R (Int) Bool)
(declare-fun S (Int) Bool)
(declare-fun dummy (Int) Bool)

(assert (or (R 0) (dummy 0)))

(assert (forall ((x Int)) (! 
    (and (not (R x)) (not (S x)))
    :pattern ((R x))
    :qid not_r_not_s
)))

(assert (forall ((x Int)) (! 
    (S x)
    :pattern ((S x))
    :qid s_true
)))
(check-sat)
```

The query is unstable (due to the same interaction between relevancy and
triggers in https://github.com/Z3Prover/z3/issues/7444): if the solver
assigns `(dummy 0)` first, it returns `unknown`.

If the solver assigns `(R 0)` first, we would expect an `unsat`. The
current implementation returns `unknown` because `not_r_not_s` leads to
a quantifier conflict, which creates `S(x)` without marking it (or any
of its ancestors) as relevant.

---------

Co-authored-by: Can Cebeci <t-cancebeci@microsoft.com>
Co-authored-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-07 13:01:44 -07:00
Nikolaj Bjorner
b2f0d0682a fix loop bug in ho_matching and add throttle configurations 2026-07-07 09:20:32 -07:00
Nikolaj Bjorner
d1aaae6856 allow lambdas in select positions for model, ignore beta redex incompletness when using arrays for MBQI 2026-07-06 17:43:15 -07:00
Nikolaj Bjorner
470e966791 bugfixes to front-end and matcher 2026-07-06 17:14:41 -07:00
Nikolaj Bjorner
6c8a5cd853 fix HO-matcher imitation curry-order and instance-assembly ordering bugs
The higher-order matcher produced ill-typed instantiations that aborted
the solve (sort-mismatch / unbound-variable exceptions), making
smt.ho_matching=true net-negative on the TPTP THF benchmarks.

Two root causes:

1. Imitation rule (ho_matcher.cpp): the select chain 'pats' is collected
   outermost-first, i.e. in reverse application order. The imitating
   lambda must curry arguments in application order (first-applied select
   binds the outermost lambda). Reversing 'pats' before building the
   domain/argument/body vectors and the lambda-wrapping loop makes the
   constructed lambda's sort agree with the flex head variable. Fixes
   unit-test ho_matcher test6c/test6d (previously asserted at
   add_binding: v->get_sort() == t->get_sort()).

2. Instance assembly (smt_quantifier.cpp on_ho_match): the fixpoint
   binding substitution used var_subst with the default std_order=true
   while the binding vector is directly indexed (binding[k] = value for
   var k). This resolved chained HO variable references against the wrong
   slots and built ill-sorted terms (assertion at rewriter_def.h:52).
   Use direct (std_order=false) substitution to match the binding layout.

Also adds defensive guards as belt-and-suspenders: subst_sorts_match
skips sort-inconsistent substitutions, an is_ground check skips bindings
with leftover de Bruijn variables, and on_ho_match catches z3_exception
to skip an unusable heuristic instance rather than aborting the solve
(re-raising only on cancellation/resource-limit).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-07-06 17:14:40 -07:00
NikolajBjorner
72d27e1cbb smt: instrument ho-matching and ho-var term-enumeration statistics
Add -st statistics counters:
- ho-matching refinements / instances (default_qm_plugin, gated on
  smt.ho_matching)
- ho-var term-enum: terms produced by mf::ho_var::populate_inst_sets
  in the model finder

Wired via a new quantifier_manager_plugin::collect_statistics virtual
forwarded from quantifier_manager::collect_statistics.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-07-06 17:14:39 -07:00
Nikolaj Bjorner
165f79a051 handle lambda equalities 2026-07-05 12:52:01 -07:00
Nikolaj Bjorner
86eae57046 disable unsound filter on equalities for beta redex completeness
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-07-04 15:42:46 -07:00
Nikolaj Bjorner
70df91bc4e fix #10039 and #10032 2026-07-04 12:43:08 -07:00
Nikolaj Bjorner
3d29d81607 Fix TPTP polymorphism crashes in final-check and model checking
Root-caused and fixed 261 debug-assertion crashes found by running Z3
across the TPTP benchmarks (-tptp -T:5 model_validate=true):

1. theory_polymorphism::final_check_eh returned FC_DONE after assigning
   the negation of its (already-true) theory assumption, which creates a
   conflict. Returning FC_DONE reported l_true while the context was
   inconsistent, tripping SASSERT(status != l_true || !inconsistent())
   in context::restart. Return FC_CONTINUE so conflict resolution turns
   it into l_false and the normal research loop runs.

2. model_evaluator::get_macro, polymorphic branch: def = subst(def)
   assigned an expr_ref temporary to a raw expr*&; the temporary freed
   the freshly substituted term, leaving def dangling (use-after-free
   during model evaluation). Pin the substituted def in m_pinned, as the
   as-array path already does.

3. smt_model_checker::add_instance: relax stale
   SASSERT(!m.is_model_value(sk_term)); get_inv may legitimately return a
   model value in polymorphic settings, already handled downstream by
   get_type_compatible_term.

Unit tests: 92 passed, 0 failed. All 261 assertion crashes resolved;
the 3 remaining files are controlled ERR_PARSER (exit 103) rejections.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-07-03 20:32:04 -07:00
Nikolaj Bjorner
348bb3b6a4 Fix memory leaks in polymorphism instantiation engine
The polymorphism theory routed polymorphic (\) problems through
theory_polymorphism, which instantiated axioms during search. Two leaks:

1. In inst::instantiate, insert_ref_map was constructed with an expr_ref
   argument, so its template parameter D deduced to expr_ref instead of
   expr*. Trail objects are region-allocated and freed without running
   destructors, so the embedded expr_ref never released its reference,
   leaking one AST subtree per instantiation. Pass e_inst.get() so D is
   expr*, matching the raw hashtable + manual inc_ref/dec_ref pattern.

2. trail_stack's destructor does not call reset(), so level-0 trail items
   (including the inc_ref balancing entries for m_from_instantiation) were
   never undone when the theory was destroyed. Added a ~theory_polymorphism
   destructor that calls m_trail.reset().

Also keeps a defensive alias check in util::unify and a fresh per-iteration
substitution in inst::instantiate.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-07-03 16:34:57 -07:00
Lev Nachmanson
7e9eef845f
smt: skip m_watches probe for unwatched literals in relevancy propagator (#10035) 2026-07-03 09:53:04 -07:00
davedets
6ac3075022
Remove unnecessary semicolons (Attempt 2) (#10020)
This is another PR towards the goal of getting Z3 to compile cleanly
when included via FetchContents into clang-tidy, which uses a pretty
strict set of warnings.

This is a second version of https://github.com/Z3Prover/z3/pull/9957. I
address @NikolajBjorner 's comments about not changing the semicolons
after macro invocations, because some editors work better with them
present. It now, to the best of my ability, only deletes semis:

* after the closing brace of namespace decl.
* after the closing brace of an extern "C" decl.
* after a function definition.

This PR is very large, but it consists entirely of deletions of
semicolons in these situations.

(If there was a way to update the previous PR, which had been closed,
and that is preferable, please let me know. I couldn't figure it out.)
2026-07-02 12:47:29 -07:00
Nikolaj Bjorner
c85e2ee2bd sort constraint
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-06-30 12:41:41 -07:00
Clemens Eisenhofer
b3143e759b
Porting seq_split to master (#9840)
Co-authored-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-06-30 10:18:28 -07:00
Nikolaj Bjorner
63259d8a43 add missing registration of lambdas with legacy array solver, add missing beta reduction axiom
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2026-06-29 19:13:46 -07:00