## Summary
Fixes a completeness regression where `elim_uncnstr` was silently
disabled for ordinary (non-polymorphic) goals, detected by the
`snapshot-regression` corpus.
- **Originating discussion:**
https://github.com/Z3Prover/bench/discussions/3054
- **Benchmark:** `iss-6260/small-2.smt2` (corpus `Z3Prover/bench`,
`inputs/issues/iss-6260/`)
- **Divergence:** recorded oracle `sat` → current z3 produces `unknown`
### Divergence diff
```diff
--- small-2.expected.out (expected)
+++ produced (current z3)
@@ -1,3 +1,3 @@
-sat
+unknown
(error "line 17 column 0: unexpected character")
(error "line 17 column 1: unexpected character")
```
(The `(error ...)` lines are expected: the benchmark contains a stray
```` ``` ```` fence on line 17. Only the `sat` → `unknown` change is the
regression.)
## Root cause
`git bisect` over the regression window pins the flip to commit
`208cc5686` ("fix build"), which added `|| m().has_type_vars()` to the
`elim_uncnstr_tactic` guard and an equivalent `if (m.has_type_vars())
return;` to the `elim_unconstrained` simplifier.
`ast_manager::has_type_vars()` is a **manager-wide, sticky** flag: it is
set to `true` as soon as *any* type variable is created, and is never
reset. In particular `finite_set_decl_plugin::init()` creates type
variables `A`/`B` to define its polymorphic signatures. Those type
variables never occur in the user's assertions, but once the finite_set
plugin is initialized — which happens while processing this benchmark —
the flag is globally `true` (confirmed by instrumenting `mk_type_var`:
the only type vars created for this benchmark are the finite_set
signature vars `A` and `B`).
As a result `elim_uncnstr` bails out for goals that contain **no**
polymorphic terms at all, i.e. it is effectively disabled. Unconstrained
subterms that used to be eliminated now reach the theory solvers.
For this benchmark the (single) assertion is `(not (xor (>= x 0) (>= x1
0) (>= x 0) x4 (str.contains ...)))`. The duplicated `(>= x 0)` cancels
(`a xor a = false`), and the free Boolean `x4` can fix the parity
regardless of the value of the `str.contains` term, so the goal is
trivially `sat`. That `str.contains`/`str.replace_re` subterm is
unconstrained and was previously removed by `elim_uncnstr`; without that
elimination it reaches `theory_seq`, which marks `str.replace_re` as
unhandled and gives up in `final_check` → `unknown` (`incomplete (theory
seq)`).
## Fix
Make the guard precise. Keep `has_type_vars()` as a cheap pre-filter
(matching existing usage in `ast_translation.cpp` and
`ast_manager::has_type_var`), but only bail out when the goal / asserted
formulas **actually** contain type-variable typed terms, using the
existing `polymorphism::util::has_type_vars(expr*)`.
This preserves the polymorphism crash-protection (goals with genuine
type-variable terms still skip `elim_uncnstr`) while restoring
`elim_uncnstr` for the vast majority of goals that merely triggered a
polymorphic-plugin initialization. Both twin guards (the `elim_uncnstr`
tactic and the `elim_unconstrained` simplifier) are fixed consistently.
## Validation
Built this checkout and re-ran the benchmark (step 5 of the fixer
workflow):
- `./configure && make -C build -j$(nproc)` — Z3 version 4.17.0.
- Unpatched master reproduced the divergence: `z3 -T:20
iss-6260/small-2.smt2` → `unknown`.
- After the fix, `z3 -T:20 inputs/issues/iss-6260/small-2.smt2` produces
**exactly** the recorded oracle:
```
sat
(error "line 17 column 0: unexpected character")
(error "line 17 column 1: unexpected character")
(error "line 17 column 2: unexpected character")
```
- Regression sanity checks: sibling `iss-6260/small.smt2` unchanged
(`sat`); plain arithmetic unconstrained goals unchanged; polymorphic
goals with genuine type-variable terms (including `declare-type-var` and
forcing `(check-sat-using (then elim-uncnstr smt))`) still solve without
crashing — the guard still fires for those.
Opened as a **draft** for human review.
> Generated by [Fix a Z3 snapshot-regression
divergence](https://github.com/Z3Prover/bench/actions/runs/28844840657)
· 861.2 AIC · ⌖ 45.8 AIC · ⊞ 8.9K ·
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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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.)
* Initial plan
* Refactor mk_and and mk_or call sites to use overloaded methods
Changed 130 call sites across 64 files to use vector overloads directly instead of manually passing .size() and .data()/.c_ptr()
Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>
* Revert mk_or changes for ptr_buffer/ptr_vector (no overload exists in ast_util.h)
* Fix compilation errors from mk_and/mk_or refactoring
Fixed type mismatches by:
- Removing m parameter for expr_ref_vector (ast_util.h has mk_and/mk_or(expr_ref_vector) overloads)
- Reverting changes for ref_buffer types (no overload exists in ast_util.h, only in ast.h for m.mk_and)
- Verified build succeeds and Z3 works correctly
Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>
* Fix test files to use correct mk_and/mk_or overloads
Changed test/doc.cpp and test/udoc_relation.cpp to use mk_and(expr_ref_vector) and mk_or(expr_ref_vector) without m parameter
Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>
---------
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>
This allows using z3 for limited E-saturation simplification.
The tactic rewrites all assertions using the E-graph induced by the equalities and instantiated equality axioms.
It does allow solving with conditionals, although this is a first inefficient cut.
The following is a sample use case that rewrites to false.
```
(declare-fun prime () Int)
(declare-fun add (Int Int) Int)
(declare-fun mul (Int Int) Int)
(declare-fun ^ (Int Int) Int)
(declare-fun sub (Int Int) Int)
(declare-fun i () Int)
(declare-fun j () Int)
(declare-fun base () Int)
(declare-fun S () (Seq Int))
(declare-fun hash ((Seq Int) Int Int Int Int) Int)
(assert (let ((a!1 (mul (seq.nth S i) (^ base (sub (sub j i) 1)))))
(let ((a!2 (mod (add (hash S base prime (add i 1) j) a!1) prime)))
(not (= (hash S base prime i j) a!2)))))
(assert (forall ((x Int))
(! (= (mod (mod x prime) prime) (mod x prime))
:pattern ((mod (mod x prime) prime)))))
(assert (forall ((x Int) (y Int))
(! (= (mod (mul x y) prime) (mod (mul (mod x prime) y) prime))
:pattern ((mod (mul x y) prime))
:pattern ((mod (mul (mod x prime) y) prime)))))
(assert (forall ((x Int) (y Int))
(! (= (mod (mul x y) prime) (mod (mul x (mod y prime)) prime))
:pattern ((mod (mul x y) prime))
:pattern ((mod (mul x (mod y prime)) prime)))))
(assert (forall ((x Int) (y Int))
(! (= (mod (add x y) prime) (mod (add x (mod y prime)) prime))
:pattern ((mod (add x y) prime))
:pattern ((mod (add x (mod y prime)) prime)))))
(assert (forall ((x Int) (y Int))
(! (= (mod (add x y) prime) (mod (add (mod x prime) y) prime))
:pattern ((mod (add x y) prime))
:pattern ((mod (add (mod x prime) y) prime)))))
(assert (forall ((x Int) (y Int))
(! (= (mul x (^ x y)) (^ x (add y 1))) :pattern ((mul x (^ x y))))))
(assert (forall ((x Int) (y Int)) (! (= (mul x y) (mul y x)) :pattern ((mul x y)))))
(assert (forall ((x Int) (y Int)) (! (= (add x y) (add y x)) :pattern ((add x y)))))
(assert (forall ((x Int) (y Int)) (! (= (mul x y) (mul y x)) :pattern ((mul x y)))))
(assert (forall ((x Int) (y Int) (z Int))
(! (= (add x (add y z)) (add (add x y) z))
:pattern ((add x (add y z)))
:pattern ((add (add x y) z)))))
(assert (forall ((x Int) (y Int) (z Int))
(! (= (mul x (mul y z)) (mul (mul x y) z))
:pattern ((mul x (mul y z)))
:pattern ((mul (mul x y) z)))))
(assert (forall ((x Int) (y Int) (z Int))
(! (= (sub (sub x y) z) (sub (sub x z) y)) :pattern ((sub (sub x y) z)))))
(assert (forall ((x Int) (y Int) (z Int))
(! (= (mul x (add y z)) (add (mul x y) (mul x z)))
:pattern ((mul x (add y z))))))
(assert (forall ((x Int)) (! (= (sub (add x 1) 1) x) :pattern ((add x 1)))))
(assert (forall ((x Int)) (! (= (add (sub x 1) 1) x) :pattern ((sub x 1)))))
(assert (let ((a!1 (^ base (sub (sub (sub j 1) i) 1))))
(let ((a!2 (mod (add (hash S base prime (add i 1) (sub j 1))
(mul (seq.nth S i) a!1))
prime)))
(= (hash S base prime i (sub j 1)) a!2))))
(assert (let ((a!1 (add (seq.nth S (- j 1)) (mul base (hash S base prime i (sub j 1))))))
(= (hash S base prime i j) (mod a!1 prime))))
(assert (let ((a!1 (add (seq.nth S (- j 1))
(mul base (hash S base prime (add i 1) (sub j 1))))))
(= (hash S base prime (add i 1) j) (mod a!1 prime))))
(apply euf-completion)
```
To use conditional rewriting you can
```
(assert (not (= 0 prime)))
```
and update axioms using modulus with prime to be of the form:
```
(=> (not (= 0 prime)) <original-body of quantifier>)
```
* Introduce X-macro-based trace tag definition
- Created trace_tags.def to centralize TRACE tag definitions
- Each tag includes a symbolic name and description
- Set up enum class TraceTag for type-safe usage in TRACE macros
* Add script to generate Markdown documentation from trace_tags.def
- Python script parses trace_tags.def and outputs trace_tags.md
* Refactor TRACE_NEW to prepend TraceTag and pass enum to is_trace_enabled
* trace: improve trace tag handling system with hierarchical tagging
- Introduce hierarchical tag-class structure: enabling a tag class activates all child tags
- Unify TRACE, STRACE, SCTRACE, and CTRACE under enum TraceTag
- Implement initial version of trace_tag.def using X(tag, tag_class, description)
(class names and descriptions to be refined in a future update)
* trace: replace all string-based TRACE tags with enum TraceTag
- Migrated all TRACE, STRACE, SCTRACE, and CTRACE macros to use enum TraceTag values instead of raw string literals
* trace : add cstring header
* trace : Add Markdown documentation generation from trace_tags.def via mk_api_doc.py
* trace : rename macro parameter 'class' to 'tag_class' and remove Unicode comment in trace_tags.h.
* trace : Add TODO comment for future implementation of tag_class activation
* trace : Disable code related to tag_class until implementation is ready (#7663).
- enforce elim-and in bool-rewriter when invoking hoisting.
- make cnf tactic more resilient to non-normalized input.
- enable eliminate predicates on ground formulas
