1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
//! Datatype theory constraint checking
#[allow(unused_imports)]
use crate::prelude::*;
use oxiz_core::ast::{TermId, TermKind, TermManager};
use super::Solver;
impl Solver {
pub(super) fn check_dt_constraints(&self, manager: &TermManager) -> bool {
// Collect positive constructor tester constraints: ((_ is Constructor) x)
let mut constructor_testers: FxHashMap<TermId, Vec<String>> = FxHashMap::default();
// Collect negative constructor tester constraints: (not ((_ is Constructor) x))
let mut negative_testers: FxHashMap<TermId, Vec<String>> = FxHashMap::default();
// Collect constructor equalities: x = Constructor(...)
let mut constructor_equalities: FxHashMap<TermId, Vec<String>> = FxHashMap::default();
// Collect DT variable equalities: x = y where both are DT variables
let mut dt_var_equalities: Vec<(TermId, TermId)> = Vec::new();
for &assertion in &self.assertions {
self.collect_dt_constraints_v2(
assertion,
manager,
&mut constructor_testers,
&mut negative_testers,
&mut constructor_equalities,
&mut dt_var_equalities,
true,
);
}
// Check: If a variable has multiple different constructor testers, it's UNSAT
for (_var, testers) in &constructor_testers {
if testers.len() > 1 {
// Multiple different constructors asserted for the same variable
// Check if they're actually different
let first = &testers[0];
for tester in testers.iter().skip(1) {
if tester != first {
return true; // Conflict: x is Constructor1 AND x is Constructor2
}
}
}
}
// Check: If a variable has a positive and negative tester for the same constructor
for (var, pos_testers) in &constructor_testers {
if let Some(neg_testers) = negative_testers.get(var) {
for pos in pos_testers {
for neg in neg_testers {
if pos == neg {
return true; // Conflict: (is Cons x) AND (not (is Cons x))
}
}
}
}
}
// Check: If a variable has different constructor equalities, it's UNSAT
for (_var, constructors) in &constructor_equalities {
if constructors.len() > 1 {
let first = &constructors[0];
for cons in constructors.iter().skip(1) {
if cons != first {
return true; // Conflict: x = Constructor1 AND x = Constructor2
}
}
}
}
// Check: If a variable has a constructor tester that conflicts with its equality
for (var, testers) in &constructor_testers {
if let Some(equalities) = constructor_equalities.get(var) {
for tester in testers {
for eq_cons in equalities {
if tester != eq_cons {
return true; // Conflict: (is Cons1 x) AND x = Cons2(...)
}
}
}
}
}
// Check: If a variable has a negative tester that conflicts with its equality
for (var, neg_testers) in &negative_testers {
if let Some(equalities) = constructor_equalities.get(var) {
for neg in neg_testers {
for eq_cons in equalities {
if neg == eq_cons {
return true; // Conflict: (not (is Cons x)) AND x = Cons(...)
}
}
}
}
}
// Check cross-variable constraints through equality
// If l1 = l2 and they have conflicting tester constraints, it's UNSAT
for &(var1, var2) in &dt_var_equalities {
// Case 1: var1 has positive tester, var2 has negative tester for same constructor
if let Some(pos1) = constructor_testers.get(&var1) {
if let Some(neg2) = negative_testers.get(&var2) {
for p in pos1 {
for n in neg2 {
if p == n {
// l1 = l2, (is Cons l1), (not (is Cons l2)) => UNSAT
return true;
}
}
}
}
}
// Case 2: var2 has positive tester, var1 has negative tester for same constructor
if let Some(pos2) = constructor_testers.get(&var2) {
if let Some(neg1) = negative_testers.get(&var1) {
for p in pos2 {
for n in neg1 {
if p == n {
// l1 = l2, (is Cons l2), (not (is Cons l1)) => UNSAT
return true;
}
}
}
}
}
// Case 3: var1 has different positive tester than var2
if let Some(pos1) = constructor_testers.get(&var1) {
if let Some(pos2) = constructor_testers.get(&var2) {
for p1 in pos1 {
for p2 in pos2 {
if p1 != p2 {
// l1 = l2, (is Cons1 l1), (is Cons2 l2) where Cons1 != Cons2 => UNSAT
return true;
}
}
}
}
}
// Case 4: var1 has constructor equality, var2 has conflicting negative tester
if let Some(eq1) = constructor_equalities.get(&var1) {
if let Some(neg2) = negative_testers.get(&var2) {
for e in eq1 {
for n in neg2 {
if e == n {
// l1 = l2, l1 = Cons(...), (not (is Cons l2)) => UNSAT
return true;
}
}
}
}
}
// Case 5: var2 has constructor equality, var1 has conflicting negative tester
if let Some(eq2) = constructor_equalities.get(&var2) {
if let Some(neg1) = negative_testers.get(&var1) {
for e in eq2 {
for n in neg1 {
if e == n {
// l1 = l2, l2 = Cons(...), (not (is Cons l1)) => UNSAT
return true;
}
}
}
}
}
// Case 6: var1 has constructor equality, var2 has conflicting positive tester
if let Some(eq1) = constructor_equalities.get(&var1) {
if let Some(pos2) = constructor_testers.get(&var2) {
for e in eq1 {
for p in pos2 {
if e != p {
// l1 = l2, l1 = Cons1(...), (is Cons2 l2) where Cons1 != Cons2 => UNSAT
return true;
}
}
}
}
}
// Case 7: var2 has constructor equality, var1 has conflicting positive tester
if let Some(eq2) = constructor_equalities.get(&var2) {
if let Some(pos1) = constructor_testers.get(&var1) {
for e in eq2 {
for p in pos1 {
if e != p {
// l1 = l2, l2 = Cons1(...), (is Cons2 l1) where Cons1 != Cons2 => UNSAT
return true;
}
}
}
}
}
// Case 8: Both have different constructor equalities
if let Some(eq1) = constructor_equalities.get(&var1) {
if let Some(eq2) = constructor_equalities.get(&var2) {
for e1 in eq1 {
for e2 in eq2 {
if e1 != e2 {
// l1 = l2, l1 = Cons1(...), l2 = Cons2(...) where Cons1 != Cons2 => UNSAT
return true;
}
}
}
}
}
}
false
}
/// Collect datatype constraints from a term (version 2 with negative testers and var equalities)
fn collect_dt_constraints_v2(
&self,
term: TermId,
manager: &TermManager,
constructor_testers: &mut FxHashMap<TermId, Vec<String>>,
negative_testers: &mut FxHashMap<TermId, Vec<String>>,
constructor_equalities: &mut FxHashMap<TermId, Vec<String>>,
dt_var_equalities: &mut Vec<(TermId, TermId)>,
in_positive_context: bool,
) {
let Some(term_data) = manager.get(term) else {
return;
};
match &term_data.kind {
TermKind::DtTester { constructor, arg } => {
let cons_name = manager.resolve_str(*constructor).to_string();
if in_positive_context {
// Positive: ((_ is Constructor) var)
constructor_testers.entry(*arg).or_default().push(cons_name);
} else {
// Negative: (not ((_ is Constructor) var))
negative_testers.entry(*arg).or_default().push(cons_name);
}
}
TermKind::Eq(lhs, rhs) => {
if in_positive_context {
// Check for x = Constructor(...)
if let Some(rhs_data) = manager.get(*rhs) {
if let TermKind::DtConstructor { constructor, .. } = &rhs_data.kind {
if self.is_dt_variable(*lhs, manager) {
constructor_equalities
.entry(*lhs)
.or_default()
.push(manager.resolve_str(*constructor).to_string());
}
}
}
if let Some(lhs_data) = manager.get(*lhs) {
if let TermKind::DtConstructor { constructor, .. } = &lhs_data.kind {
if self.is_dt_variable(*rhs, manager) {
constructor_equalities
.entry(*rhs)
.or_default()
.push(manager.resolve_str(*constructor).to_string());
}
}
}
// Check for DT variable equality: x = y where both are DT variables
if self.is_dt_variable(*lhs, manager) && self.is_dt_variable(*rhs, manager) {
dt_var_equalities.push((*lhs, *rhs));
}
}
self.collect_dt_constraints_v2(
*lhs,
manager,
constructor_testers,
negative_testers,
constructor_equalities,
dt_var_equalities,
in_positive_context,
);
self.collect_dt_constraints_v2(
*rhs,
manager,
constructor_testers,
negative_testers,
constructor_equalities,
dt_var_equalities,
in_positive_context,
);
}
TermKind::And(args) => {
for &arg in args {
self.collect_dt_constraints_v2(
arg,
manager,
constructor_testers,
negative_testers,
constructor_equalities,
dt_var_equalities,
in_positive_context,
);
}
}
TermKind::Or(_args) => {
// Don't collect from OR branches - they represent disjunctions, not conjunctions
// If we collected from both branches of (or (= x A) (= x B)), we'd falsely detect a conflict
}
TermKind::Not(inner) => {
// Flip context when entering Not
self.collect_dt_constraints_v2(
*inner,
manager,
constructor_testers,
negative_testers,
constructor_equalities,
dt_var_equalities,
!in_positive_context,
);
}
_ => {}
}
}
/// Collect datatype constraints from a term
fn collect_dt_constraints(
&self,
term: TermId,
manager: &TermManager,
constructor_testers: &mut FxHashMap<TermId, Vec<String>>,
constructor_equalities: &mut FxHashMap<TermId, Vec<String>>,
) {
self.collect_dt_constraints_inner(
term,
manager,
constructor_testers,
constructor_equalities,
true,
);
}
fn collect_dt_constraints_inner(
&self,
term: TermId,
manager: &TermManager,
constructor_testers: &mut FxHashMap<TermId, Vec<String>>,
constructor_equalities: &mut FxHashMap<TermId, Vec<String>>,
in_positive_context: bool,
) {
let Some(term_data) = manager.get(term) else {
return;
};
match &term_data.kind {
TermKind::DtTester { constructor, arg } if in_positive_context => {
// ((_ is Constructor) var) - only collect when in positive context
constructor_testers
.entry(*arg)
.or_default()
.push(manager.resolve_str(*constructor).to_string());
}
TermKind::Eq(lhs, rhs) => {
// Check for x = Constructor(...) - only collect when in positive context
if in_positive_context {
if let Some(rhs_data) = manager.get(*rhs) {
if let TermKind::DtConstructor { constructor, .. } = &rhs_data.kind {
if self.is_dt_variable(*lhs, manager) {
constructor_equalities
.entry(*lhs)
.or_default()
.push(manager.resolve_str(*constructor).to_string());
}
}
}
if let Some(lhs_data) = manager.get(*lhs) {
if let TermKind::DtConstructor { constructor, .. } = &lhs_data.kind {
if self.is_dt_variable(*rhs, manager) {
constructor_equalities
.entry(*rhs)
.or_default()
.push(manager.resolve_str(*constructor).to_string());
}
}
}
}
self.collect_dt_constraints_inner(
*lhs,
manager,
constructor_testers,
constructor_equalities,
in_positive_context,
);
self.collect_dt_constraints_inner(
*rhs,
manager,
constructor_testers,
constructor_equalities,
in_positive_context,
);
}
TermKind::And(args) => {
for &arg in args {
self.collect_dt_constraints_inner(
arg,
manager,
constructor_testers,
constructor_equalities,
in_positive_context,
);
}
}
TermKind::Or(_args) => {
// Don't collect from OR branches - they represent disjunctions, not conjunctions
// If we collected from both branches of (or (= x A) (= x B)), we'd falsely detect a conflict
}
TermKind::Not(inner) => {
// Flip context when entering Not
self.collect_dt_constraints_inner(
*inner,
manager,
constructor_testers,
constructor_equalities,
!in_positive_context,
);
}
_ => {}
}
}
/// Check if a term is a datatype variable
fn is_dt_variable(&self, term: TermId, manager: &TermManager) -> bool {
let Some(term_data) = manager.get(term) else {
return false;
};
matches!(term_data.kind, TermKind::Var(_))
}
}