File size: 41,938 Bytes
760f90e
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
import OAI.Computability.Scheduling.PolynomialLists

namespace OAI

section
open Lean in
private def polyCostNames : Array Name := #[
  `OAI.ThreeMachine.StackCompiler.Costs.matrixGet,
  `OAI.ThreeMachine.StackCompiler.Costs.finEq,
  `OAI.ThreeMachine.StackCompiler.Costs.setMem,
  `OAI.ThreeMachine.StackCompiler.Costs.setSubset,
  `OAI.ThreeMachine.StackCompiler.Costs.setEq,
  `OAI.ThreeMachine.StackCompiler.Costs.setInter,
  `OAI.ThreeMachine.StackCompiler.Costs.setDiff,
  `OAI.ThreeMachine.StackCompiler.Costs.setDisjoint,
  `OAI.ThreeMachine.StackCompiler.Costs.noEdgeTest,
  `OAI.ThreeMachine.StackCompiler.Costs.noEdgeRow,
  `OAI.ThreeMachine.StackCompiler.Costs.noEdges,
  `OAI.ThreeMachine.StackCompiler.Costs.stateEqL,
  `OAI.ThreeMachine.StackCompiler.Costs.stateEqM,
  `OAI.ThreeMachine.StackCompiler.Costs.stateEqR,
  `OAI.ThreeMachine.StackCompiler.Costs.stateEqMR,
  `OAI.ThreeMachine.StackCompiler.Costs.stateEqLMR,
  `OAI.ThreeMachine.StackCompiler.Costs.stateEq,
  `OAI.ThreeMachine.StackCompiler.Costs.setCard,
  `OAI.ThreeMachine.StackCompiler.Costs.setUnion,
  `OAI.ThreeMachine.StackCompiler.Costs.stateCandidate,
  `OAI.ThreeMachine.StackCompiler.Costs.stateUpto,
  `OAI.ThreeMachine.StackCompiler.Costs.scLZ,
  `OAI.ThreeMachine.StackCompiler.Costs.scLZR,
  `OAI.ThreeMachine.StackCompiler.Costs.scA,
  `OAI.ThreeMachine.StackCompiler.Costs.scB,
  `OAI.ThreeMachine.StackCompiler.Costs.scC,
  `OAI.ThreeMachine.StackCompiler.Costs.scD,
  `OAI.ThreeMachine.StackCompiler.Costs.scE,
  `OAI.ThreeMachine.StackCompiler.Costs.scF,
  `OAI.ThreeMachine.StackCompiler.Costs.scH,
  `OAI.ThreeMachine.StackCompiler.Costs.scI,
  `OAI.ThreeMachine.StackCompiler.Costs.scJ,
  `OAI.ThreeMachine.StackCompiler.Costs.scIJ,
  `OAI.ThreeMachine.StackCompiler.Costs.scHIJ,
  `OAI.ThreeMachine.StackCompiler.Costs.scFHIJ,
  `OAI.ThreeMachine.StackCompiler.Costs.scEFHIJ,
  `OAI.ThreeMachine.StackCompiler.Costs.scDEFHIJ,
  `OAI.ThreeMachine.StackCompiler.Costs.scCDEFHIJ,
  `OAI.ThreeMachine.StackCompiler.Costs.scBCDEFHIJ,
  `OAI.ThreeMachine.StackCompiler.Costs.scAll,
  `OAI.ThreeMachine.StackCompiler.Costs.stateCompatible,
  `OAI.ThreeMachine.StackCompiler.Costs.blockEmpty,
  `OAI.ThreeMachine.StackCompiler.Costs.blockTriple,
  `OAI.ThreeMachine.StackCompiler.Costs.statesC,
  `OAI.ThreeMachine.StackCompiler.Costs.statesP,
  `OAI.ThreeMachine.StackCompiler.Costs.paddedCell,
  `OAI.ThreeMachine.StackCompiler.Costs.paddedMatrix,
  `OAI.ThreeMachine.StackCompiler.Costs.restrictTimeBound,
  `OAI.ThreeMachine.StackCompiler.Costs.predecessorCell,
  `OAI.ThreeMachine.StackCompiler.Costs.predecessorCount,
  `OAI.ThreeMachine.StackCompiler.Costs.predecessorsBody,
  `OAI.ThreeMachine.StackCompiler.Costs.predecessors,
  `OAI.ThreeMachine.StackCompiler.Costs.rank,
  `OAI.ThreeMachine.StackCompiler.Costs.ranks,
  `OAI.ThreeMachine.StackCompiler.Costs.matrixGetFrame,
  `OAI.ThreeMachine.StackCompiler.Costs.conePred,
  `OAI.ThreeMachine.StackCompiler.Costs.cone,
  `OAI.ThreeMachine.StackCompiler.Costs.triplesE,
  `OAI.ThreeMachine.StackCompiler.Costs.triplesA,
  `OAI.ThreeMachine.StackCompiler.Costs.triplesP,
  `OAI.ThreeMachine.StackCompiler.Costs.triples,
  `OAI.ThreeMachine.StackCompiler.Costs.conesF,
  `OAI.ThreeMachine.StackCompiler.Costs.conesOne,
  `OAI.ThreeMachine.StackCompiler.Costs.cones,
  `OAI.ThreeMachine.StackCompiler.Costs.thresholds,
  `OAI.ThreeMachine.StackCompiler.Costs.atomSetsC,
  `OAI.ThreeMachine.StackCompiler.Costs.atomSetsT,
  `OAI.ThreeMachine.StackCompiler.Costs.atomSetsD,
  `OAI.ThreeMachine.StackCompiler.Costs.atomSets,
  `OAI.ThreeMachine.StackCompiler.Costs.evalTemplatesCanonical,
  `OAI.ThreeMachine.StackCompiler.Costs.familyAssignments,
  `OAI.ThreeMachine.StackCompiler.Costs.familyEval,
  `OAI.ThreeMachine.StackCompiler.Costs.family,
  `OAI.ThreeMachine.StackCompiler.Costs.fullSolve,
  `OAI.ThreeMachine.StackCompiler.Costs.paddedSolve,
  `OAI.ThreeMachine.StackCompiler.Costs.scheduleRestriction,
  `OAI.ThreeMachine.StackCompiler.Costs.scheduleCandidate,
  `OAI.ThreeMachine.StackCompiler.Costs.scheduleMatrixFixed,
  `OAI.ThreeMachine.StackCompiler.Costs.scheduleMatrix,
  `OAI.ThreeMachine.StackCompiler.Costs.edgePairEq,
  `OAI.ThreeMachine.StackCompiler.Costs.edgeAt,
  `OAI.ThreeMachine.StackCompiler.Costs.edgeMatrix,
  `OAI.ThreeMachine.StackCompiler.Costs.nextMatrixCell,
  `OAI.ThreeMachine.StackCompiler.Costs.nextMatrix,
  `OAI.ThreeMachine.StackCompiler.Costs.closureMatrixStep,
  `OAI.ThreeMachine.StackCompiler.Costs.reachMatrix
]

open Lean Meta Elab Tactic in
private def polyAutoCostHead (e : Expr) : Option Name :=
  let e := e.consumeMData
  let as := e.getAppArgs
  if e.getAppFn.isConstOf ``ThreeMachine.StackCompiler.Uniform.time && as.size ≥ 3 then
    as[as.size-3]!.getAppFn.constName?
  else if e.getAppFn.isConstOf ``ThreeMachine.StackCompiler.Realizer.time && as.size ≥ 2 then
    as[as.size-2]!.getAppFn.constName?
  else none

open Lean Meta Elab Tactic in
private def polyAutoExprName (e : Expr) (n : Name) : Bool := e.consumeMData.getAppFn.isConstOf n

open Lean Meta Elab Tactic in
private def withPolyFacts (hs : List Expr) (k : TacticM (Expr × Expr)) : TacticM (Expr × Expr) := do
  match hs with
  | [] => k
  | h::hs =>
    withLetDecl `polyFact (← instantiateMVars (← inferType h)) h fun v => do
      let (a,b) ← withPolyFacts hs k
      return (a.replaceFVar v h,b.replaceFVar v h)

open Lean Meta Elab Tactic in
private def polyAutoRule (e : Expr) : TacticM (Option (Expr × Expr)) := do
  let some rh := polyAutoCostHead e | return none
  let es := e.getAppArgs
  for nm in polyRuleNames do
    if !(← getEnv).contains nm then continue
    let saved ← saveState
    try
      let mut raw := (← getConstInfo nm).type
      while raw.isForall do raw := raw.bindingBody!
      let rargs := raw.getAppArgs
      if rargs.size < 2 then throwError "not a bound"
      unless polyAutoCostHead rargs[rargs.size-2]! == some rh do throwError "different routine"
      let c ← mkConstWithFreshMVarLevels nm
      let (xs,bs,tp) ← forallMetaTelescope (← inferType c)
      let args := tp.getAppArgs
      if args.size < 2 then throwError "not a bound"
      let lhs := args[args.size-2]!
      let rhs := args[args.size-1]!
      unless polyAutoCostHead lhs == some rh do throwError "different routine"
      let lhsArgs := lhs.getAppArgs
      let rpos := if lhs.getAppFn.isConstOf ``ThreeMachine.StackCompiler.Uniform.time then lhsArgs.size-3 else lhsArgs.size-2
      let lr := lhsArgs[rpos]!
      let rr := es[if e.getAppFn.isConstOf ``ThreeMachine.StackCompiler.Uniform.time then es.size-3 else es.size-2]!
      if lr.getAppArgs.size == rr.getAppArgs.size then
        for (a,b) in lr.getAppArgs.zip rr.getAppArgs do
          unless ← isDefEq a b do throwError "routine argument does not match"
      unless ← isDefEq lhs e do throwError "bound does not match"
      for k in [:xs.size] do
        if ← xs[k]!.mvarId!.isAssigned then pure ()
        else if bs[k]! == BinderInfo.instImplicit then
          let v ← synthInstance (← inferType xs[k]!)
          xs[k]!.mvarId!.assign v
      let p ← instantiateMVars (mkAppN c xs)
      if p.hasMVar then throwError "bound has unresolved hypotheses"
      let rhs ← instantiateMVars rhs
      let p ← if tp.getAppFn.isConstOf ``Eq then mkAppM ``le_of_eq #[p] else pure p
      return some (rhs,p)
    catch _ => saved.restore
  return none

open Lean Meta Elab Tactic in
private def polyAutoEstimate (e x : Expr) : TacticM (Option (Expr × Expr × Expr)) := do
  let some rh := polyAutoCostHead e | return none
  let es := e.getAppArgs
  unless e.getAppFn.isConstOf ``ThreeMachine.StackCompiler.Uniform.time do return none
  for nm in polyCostNames do
    if !(← getEnv).contains nm then continue
    let saved ← saveState
    try
      let c ← mkConstWithFreshMVarLevels nm
      let (xs,bs,tp) ← forallMetaTelescope (← inferType c)
      let tp := tp.consumeMData
      unless tp.isAppOf ``ThreeMachine.StackCompiler.Poly do throwError "not polynomial"
      let args := tp.getAppArgs
      let domain := args[0]!
      let sigmaArgs := domain.getAppArgs
      unless domain.isAppOf ``Sigma do throwError "not sigma domain"
      let fn := args[2]!
      withLocalDeclD `p domain fun p => do
        let body := (mkApp fn p).headBeta
        unless polyAutoCostHead body == some rh do throwError "different routine"
        let bs := body.getAppArgs
        unless ← isDefEq bs[bs.size-3]! es[es.size-3]! do throwError "different routine args"
      let v ← mkAppOptM ``Sigma.mk #[some sigmaArgs[0]!,some sigmaArgs[1]!,some es[es.size-2]!,some es.back!]
      for k in [:xs.size] do
        if ← xs[k]!.mvarId!.isAssigned then pure ()
        else if bs[k]! == BinderInfo.instImplicit then
          xs[k]!.mvarId!.assign (← synthInstance (← inferType xs[k]!))
      let h ← instantiateMVars (mkAppN c xs)
      if h.hasMVar then throwError "bound has unresolved hypotheses"
      let g ← mkLambdaFVars #[x] v
      return some (h,g,← instantiateMVars (mkApp args[1]! v))
    catch _ => saved.restore
  return none

open Lean Meta Elab Tactic in
private def polyAutoDegree (p : Expr) : TacticM Expr := do
  let tp := (← instantiateMVars (← inferType p)).consumeMData
  let tp ← withReducible <| whnf tp
  if tp.isAppOfArity ``ThreeMachine.StackCompiler.Poly 4 then
    return tp.getAppArgs[3]!

  throwError "poly_auto: unexpected result type {tp} of {p}"

open Lean Meta Elab Tactic in
private def synthPolyAuto (cache : IO.Ref (Std.HashMap (Expr × Expr × Expr) (Expr × Expr))) (fuel : ℕ) (sz x e : Expr) : TacticM (Expr × Expr) := do
  let key := (sz,x,e)
  if let some r := (← cache.get)[key]? then return r
  let result ← (do
   match fuel with
   | 0 => throwError "poly_auto: expression depth exhausted"
   | fuel+1 =>
     let e ← withReducible <| whnf (← deltaExpand e (fun n =>
       [``Function.comp,``ThreeMachine.Algorithm.Block.append,``ThreeMachine.Algorithm.State.advance,
        ``ThreeMachine.Algorithm.State.finish,``ThreeMachine.Algorithm.Block.empty,
        ``ThreeMachine.Algorithm.Block.triple].contains n)).headBeta
     let fn ← mkLambdaFVars #[x] e
     for decl in (← getLCtx) do
       unless decl.isImplementationDetail do
         let tp := (← instantiateMVars decl.type).consumeMData
         if polyAutoExprName tp ``ThreeMachine.StackCompiler.Poly then
           let as := tp.getAppArgs
           if as.size == 4 then
             if ← withReducible <| isDefEq (← deltaExpand as[1]! (· == ``Function.comp)) sz then
               let factFn ← deltaExpand as[2]! (fun n =>
                 [``Function.comp,``ThreeMachine.Algorithm.Block.append,``ThreeMachine.Algorithm.State.advance,
                  ``ThreeMachine.Algorithm.State.finish,``ThreeMachine.Algorithm.Block.empty,
                  ``ThreeMachine.Algorithm.Block.triple].contains n)
               let same ← withReducible <| isDefEq factFn fn
               let factBody ← withReducible <| whnf (mkApp factFn x).headBeta
               let same ← if same then pure true else if
                   e.getAppFn.isConstOf ``ThreeMachine.StackCompiler.volume &&
                   factBody.getAppFn.isConstOf ``ThreeMachine.StackCompiler.volume then

                 if ← withReducible <| isDefEq factBody.getAppArgs.back! e.getAppArgs.back! then
                   withTransparency .all <| isDefEq factFn fn
                 else pure false
               else pure false
               if same then
                 return (as[3]!,decl.toExpr)
     if !(e.containsFVar x.fvarId!) then
       return (mkNatLit 0, ← mkAppM ``ThreeMachine.StackCompiler.Poly.const #[sz,e])
     let se := mkApp sz x
     if ← withReducible <| isDefEq e se then
       return (mkNatLit 1, ← mkAppM ``ThreeMachine.StackCompiler.Poly.size #[sz])
     let be ← mkAppM ``Nat.add #[se,mkNatLit 2]
     if ← withReducible <| isDefEq e be then
       return (mkNatLit 1, ← mkAppM ``ThreeMachine.StackCompiler.Poly.base #[sz])
     let es := e.getAppArgs
     let isadd := polyAutoExprName e ``Nat.add || polyAutoExprName e ``HAdd.hAdd
     let ismul := polyAutoExprName e ``Nat.mul || polyAutoExprName e ``HMul.hMul
     let issub := polyAutoExprName e ``Nat.sub || polyAutoExprName e ``HSub.hSub
     let ismax := polyAutoExprName e ``Nat.max || polyAutoExprName e ``Max.max
     if es.size ≥ 2 && (isadd || ismul || issub || ismax) then
       let a := es[es.size-2]!
       let b := es[es.size-1]!
       let (d,h) ← synthPolyAuto cache fuel sz x a
       if issub then
         let g ← mkLambdaFVars #[x] b
         return (d, ← mkAppM ``ThreeMachine.StackCompiler.Poly.sub #[h,g])
       let (_,h') ← synthPolyAuto cache fuel sz x b
       let nm := if isadd then ``ThreeMachine.StackCompiler.Poly.add
         else if ismul then ``ThreeMachine.StackCompiler.Poly.mul
         else ``ThreeMachine.StackCompiler.Poly.max
       let proof ← mkAppM nm #[h,h']
       return (← polyAutoDegree proof,proof)
     if e.isAppOfArity ``ite 5 then
       let pf ← mkLambdaFVars #[x] es[1]!
       let (_,h) ← synthPolyAuto cache fuel sz x es[3]!
       let (_,h') ← synthPolyAuto cache fuel sz x es[4]!
       let proof ← mkAppM ``ThreeMachine.StackCompiler.Poly.iteNat #[pf,h,h']
       return (← polyAutoDegree proof,proof)
     if es.size ≥ 2 && (polyAutoExprName e ``Nat.pow || polyAutoExprName e ``HPow.hPow) &&
         !(es[es.size-1]!.containsFVar x.fvarId!) then
       let (_,h) ← synthPolyAuto cache fuel sz x es[es.size-2]!
       let proof ← mkAppM ``ThreeMachine.StackCompiler.Poly.pow #[h,es[es.size-1]!]
       return (← polyAutoDegree proof,proof)
     if es.size == 1 && polyAutoExprName e ``Nat.succ then
       let (_,h) ← synthPolyAuto cache fuel sz x es[0]!
       let hc ← mkAppM ``ThreeMachine.StackCompiler.Poly.const #[sz,mkNatLit 1]
       let proof ← mkAppM ``ThreeMachine.StackCompiler.Poly.add #[h,hc]
       return (← polyAutoDegree proof,proof)
     if let .proj ``Fin 0 v := e then
       let tp ← inferType v
       let n := tp.getAppArgs[0]!
       let (_,h) ← synthPolyAuto cache fuel sz x n
       let vf ← mkLambdaFVars #[x] v
       let proof ← mkAppM ``ThreeMachine.StackCompiler.Poly.finVal #[h,vf]
       return (← polyAutoDegree proof,proof)
     if e.isAppOfArity ``Fin.val 2 then
       let (_,h) ← synthPolyAuto cache fuel sz x es[0]!
       let vf ← mkLambdaFVars #[x] es[1]!
       let proof ← mkAppM ``ThreeMachine.StackCompiler.Poly.finVal #[h,vf]
       return (← polyAutoDegree proof,proof)
     let block? := match e with
       | .proj ``ThreeMachine.Algorithm.Block 0 b => some b
       | _ => if polyAutoExprName e ``ThreeMachine.Algorithm.Block.length then some es.back! else none
     if let some b := block? then
       let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[b])
       let bf ← mkLambdaFVars #[x] b
       let pr ← mkAppM ``ThreeMachine.StackCompiler.Poly.blockLength #[bf,h]
       return (← polyAutoDegree pr,pr)
     if polyAutoExprName e ``Finset.card then
       let v ← withReducible <| whnf (← deltaExpand es[es.size-1]! (· == ``Function.comp)).headBeta
       let tp ← withReducible <| whnf (← inferType v)
       let elem ← withReducible <| whnf tp.getAppArgs[0]!
       if polyAutoExprName elem ``Fin then
         let (_,h) ← synthPolyAuto cache fuel sz x elem.getAppArgs[0]!
         let vf ← mkLambdaFVars #[x] v
         let proof ← mkAppM ``ThreeMachine.StackCompiler.Poly.finsetCard #[h,vf]
         return (← polyAutoDegree proof,proof)
     if polyAutoExprName e ``List.length then
       let v ← withReducible <| whnf (← deltaExpand es[es.size-1]! (· == ``Function.comp)).headBeta
       if polyAutoExprName v ``List.nil then
         return (mkNatLit 0, ← mkAppM ``ThreeMachine.StackCompiler.Poly.const #[sz,mkNatLit 0])
       if polyAutoExprName v ``List.cons then
         let va := v.getAppArgs
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``List.length #[va.back!])
         let af ← mkLambdaFVars #[x] va[va.size-2]!
         let xf ← mkLambdaFVars #[x] va.back!
         let pr ← mkAppM ``ThreeMachine.StackCompiler.Poly.lengthCons #[af,xf,h]
         return (← polyAutoDegree pr,pr)
       if polyAutoExprName v ``List.tail || polyAutoExprName v ``List.reverse then
         let xs := v.getAppArgs.back!
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``List.length #[xs])
         let xf ← mkLambdaFVars #[x] xs
         let nm := if polyAutoExprName v ``List.tail then
           ``ThreeMachine.StackCompiler.Poly.lengthTail else ``ThreeMachine.StackCompiler.Poly.lengthReverse
         let pr ← mkAppM nm #[xf,h]
         return (← polyAutoDegree pr,pr)
       if polyAutoExprName v ``List.take || polyAutoExprName v ``List.drop then
         let va := v.getAppArgs
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``List.length #[va.back!])
         let kf ← mkLambdaFVars #[x] va[va.size-2]!
         let xf ← mkLambdaFVars #[x] va.back!
         let nm := if polyAutoExprName v ``List.take then
           ``ThreeMachine.StackCompiler.Poly.lengthTake else ``ThreeMachine.StackCompiler.Poly.lengthDrop
         let pr ← mkAppM nm #[kf,xf,h]
         return (← polyAutoDegree pr,pr)
       if polyAutoExprName v ``List.append || polyAutoExprName v ``HAppend.hAppend || polyAutoExprName v ``Append.append then
         let va := v.getAppArgs
         let a := va[va.size-2]!
         let b := va.back!
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``List.length #[a])
         let (_,h') ← synthPolyAuto cache fuel sz x (← mkAppM ``List.length #[b])
         let af ← mkLambdaFVars #[x] a
         let bf ← mkLambdaFVars #[x] b
         let pr ← mkAppM ``ThreeMachine.StackCompiler.Poly.lengthAppend #[af,bf,h,h']
         return (← polyAutoDegree pr,pr)
       if polyAutoExprName v ``List.range then
         let (_,h) ← synthPolyAuto cache fuel sz x v.getAppArgs.back!
         let kf ← mkLambdaFVars #[x] v.getAppArgs.back!
         let pr ← mkAppM ``ThreeMachine.StackCompiler.Poly.lengthRange #[kf,h]
         return (← polyAutoDegree pr,pr)
       if polyAutoExprName v ``List.replicate then
         let va := v.getAppArgs
         let (_,h) ← synthPolyAuto cache fuel sz x va[va.size-2]!
         let kf ← mkLambdaFVars #[x] va[va.size-2]!
         let af ← mkLambdaFVars #[x] va.back!
         let pr ← mkAppM ``ThreeMachine.StackCompiler.Poly.lengthReplicate #[kf,af,h]
         return (← polyAutoDegree pr,pr)
       if polyAutoExprName v ``Option.toList then
         let ofn ← mkLambdaFVars #[x] v.getAppArgs.back!
         let pr ← mkAppOptM ``ThreeMachine.StackCompiler.Poly.lengthOption #[none,some sz,none,some ofn]
         return (← polyAutoDegree pr,pr)
       if polyAutoExprName v ``List.map then
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``List.length #[v.getAppArgs.back!])
         let ff ← mkLambdaFVars #[x] v.getAppArgs[v.getAppArgs.size-2]!
         let pr ← mkAppM ``ThreeMachine.StackCompiler.Poly.lengthMap #[ff,h]
         return (← polyAutoDegree pr,pr)
       if polyAutoExprName v ``List.product then
         let vs := v.getAppArgs
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``List.length #[vs[vs.size-2]!])
         let (_,h') ← synthPolyAuto cache fuel sz x (← mkAppM ``List.length #[vs.back!])
         let pr ← mkAppM ``ThreeMachine.StackCompiler.Poly.lengthProduct #[h,h']
         return (← polyAutoDegree pr,pr)
       if polyAutoExprName v ``List.filter then
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``List.length #[v.getAppArgs.back!])
         let pf ← mkLambdaFVars #[x] v.getAppArgs[v.getAppArgs.size-2]!
         let pr ← mkAppM ``ThreeMachine.StackCompiler.Poly.lengthFilter #[pf,h]
         return (← polyAutoDegree pr,pr)
       if polyAutoExprName v ``List.finRange then
         let (_,h) ← synthPolyAuto cache fuel sz x v.getAppArgs[0]!
         let pr ← mkAppM ``ThreeMachine.StackCompiler.Poly.lengthFinRange #[h]
         return (← polyAutoDegree pr,pr)
       if polyAutoExprName v ``Finset.sort then
         let set := v.getAppArgs[1]!
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``Finset.card #[set])
         let sf ← mkLambdaFVars #[x] set
         let pr ← mkAppM ``ThreeMachine.StackCompiler.Poly.lengthSort #[sf,h]
         return (← polyAutoDegree pr,pr)
       if polyAutoExprName v ``List.ofFn then
         let fn := v.getAppArgs.back!
         let (_,h) ← synthPolyAuto cache fuel sz x v.getAppArgs[1]!
         let ff ← mkLambdaFVars #[x] fn
         let pr ← mkAppM ``ThreeMachine.StackCompiler.Poly.lengthOfFn #[ff,h]
         return (← polyAutoDegree pr,pr)
       let vfn ← mkLambdaFVars #[x] (← mkAppM ``ThreeMachine.StackCompiler.volume #[v])
       for decl in (← getLCtx) do
         let dt := (← instantiateMVars decl.type).consumeMData
         if polyAutoExprName dt ``ThreeMachine.StackCompiler.Poly then
           let da := dt.getAppArgs
           if (← withReducible <| isDefEq da[1]! sz) && (← withReducible <| isDefEq da[2]! vfn) then
             let vf ← mkLambdaFVars #[x] v
             let pr ← mkAppM ``ThreeMachine.StackCompiler.Poly.lengthVolume #[vf,decl.toExpr]
             return (← polyAutoDegree pr,pr)
       throwError "poly_auto: no length bound for {v}"
     if polyAutoExprName e ``ThreeMachine.StackCompiler.volume then
       let val ← withReducible <| whnf (← deltaExpand es[es.size-1]! (· == ``Function.comp)).headBeta
       let vf ← mkLambdaFVars #[x] val
       let tp ← withReducible <| whnf (← inferType val)
       let ts := tp.getAppArgs
       let finish (pr : Expr) : TacticM (Expr × Expr) := do
         return (← polyAutoDegree pr,pr)
       if polyAutoExprName val ``List.nil then
         return (mkNatLit 0, ← mkAppM ``ThreeMachine.StackCompiler.Poly.const #[sz,mkNatLit 1])
       if val.isAppOfArity ``ite 5 then
         let vs := val.getAppArgs
         let pf ← mkLambdaFVars #[x] vs[1]!
         let af ← mkLambdaFVars #[x] vs[3]!
         let bf ← mkLambdaFVars #[x] vs[4]!
         let (_,ha) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[vs[3]!])
         let (_,hb) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[vs[4]!])
         return ← finish (← mkAppM ``ThreeMachine.StackCompiler.Poly.volumeIte #[pf,af,bf,ha,hb])
       if polyAutoExprName val ``ThreeMachine.Algorithm.lookup then
         let vs := val.getAppArgs
         let xs := vs[vs.size-2]!
         let k := vs.back!
         let xf ← mkLambdaFVars #[x] xs
         let kf ← mkLambdaFVars #[x] k
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[xs])
         return ← finish (← mkAppM ``ThreeMachine.StackCompiler.Poly.volumeLookup #[xf,kf,h])
       if polyAutoExprName val ``Option.toList then
         let o := val.getAppArgs.back!
         let ofn ← mkLambdaFVars #[x] o
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[o])
         return ← finish (← mkAppM ``ThreeMachine.StackCompiler.Poly.volumeOptionToList #[ofn,h])
       if polyAutoExprName val ``Option.some then
         let a := val.getAppArgs.back!
         let af ← mkLambdaFVars #[x] a
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[a])
         return ← finish (← mkAppM ``ThreeMachine.StackCompiler.Poly.volumeOptionSome #[af,h])
       if polyAutoExprName val ``Option.map then
         let vs := val.getAppArgs
         let f := vs[vs.size-2]!
         let o := vs.back!
         let ofn ← mkLambdaFVars #[x] o
         let ff ← mkLambdaFVars #[x] f
         let listFn ← mkLambdaFVars #[x] (← mkAppM ``Option.toList #[o])
         let pool ← mkAppM ``ThreeMachine.StackCompiler.Poly.ListPool #[listFn]
         let (_,ho) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[o])
         let locals := (← getLCtx).decls.toArray.filterMap (fun d => d)
         let xd ← inferType x
         let hf ← withLocalDeclD `q pool fun q => do
           let root ← mkAppM ``Sigma.fst #[q]
           let item ← mkAppM ``Subtype.val #[← mkAppM ``Sigma.snd #[q]]
           let szNew ← mkLambdaFVars #[q] (mkApp sz root)
           let rootFn ← mkLambdaFVars #[q] root
           let mut hs : Array Expr := #[]
           for decl in locals do
             let dt := (← instantiateMVars decl.type).consumeMData
             if polyAutoExprName dt ``ThreeMachine.StackCompiler.Poly then
               if (← withReducible <| isDefEq dt.getAppArgs[0]! xd) then
                 hs := hs.push (← mkAppM ``ThreeMachine.StackCompiler.Poly.precomp #[decl.toExpr,rootFn])
           let hlist ← mkAppM ``ThreeMachine.StackCompiler.Poly.volumeOptionToList #[ofn,ho]
           hs := hs.push (← mkAppM ``ThreeMachine.StackCompiler.Poly.volumePool #[listFn,hlist])
           let (_,pr) ← withPolyFacts hs.toList do
             synthPolyAuto cache fuel szNew q (← mkAppM ``ThreeMachine.StackCompiler.volume #[mkApp (f.replaceFVar x root) item])
           return pr
         return ← finish (← mkAppOptM ``ThreeMachine.StackCompiler.Poly.volumeOptionMap #[none,some sz,none,none,none,none,some ff,some ofn,some hf])
       if polyAutoExprName val ``Option.none then
         let h ← mkAppM ``ThreeMachine.StackCompiler.Poly.const #[sz,mkNatLit 1]
         return ← finish h
       let blockTime? := match val with
         | .proj ``ThreeMachine.Algorithm.Block 1 b => some b
         | _ => if polyAutoExprName val ``ThreeMachine.Algorithm.Block.time then some val.getAppArgs.back! else none
       if let some b := blockTime? then
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[b])
         let bf ← mkLambdaFVars #[x] b
         return ← finish (← mkAppM ``ThreeMachine.StackCompiler.Poly.blockTime #[bf,h])

       let proj? := match val with
         | .proj ``Prod k p => some (k,p)
         | _ => if polyAutoExprName val ``Prod.fst then some (0,val.getAppArgs.back!)
              else if polyAutoExprName val ``Prod.snd then some (1,val.getAppArgs.back!) else none
       if let some (k,p) := proj? then
         let pf ← mkLambdaFVars #[x] p
         let pv ← mkLambdaFVars #[x] (← mkAppM ``ThreeMachine.StackCompiler.volume #[p])
         for decl in (← getLCtx) do
           let dt := (← instantiateMVars decl.type).consumeMData
           if polyAutoExprName dt ``ThreeMachine.StackCompiler.Poly then
             let ds := dt.getAppArgs
             if (← withReducible <| isDefEq ds[1]! sz) && (← withReducible <| isDefEq ds[2]! pv) then
               return ← finish (← mkAppM (if k == 0 then ``ThreeMachine.StackCompiler.Poly.volumeFst else
                 ``ThreeMachine.StackCompiler.Poly.volumeSnd) #[pf,decl.toExpr])
       if polyAutoExprName val ``Finset.sort then
         let set := val.getAppArgs[1]!
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[set])
         return ← finish h
       if polyAutoExprName val ``List.ofFn then
         let f := val.getAppArgs.back!
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[f])
         return ← finish h
       if polyAutoExprName val ``List.finRange then
         let (_,h) ← synthPolyAuto cache fuel sz x val.getAppArgs[0]!
         return ← finish (← mkAppM ``ThreeMachine.StackCompiler.Poly.volumeFinRange #[h])
       if polyAutoExprName tp ``Nat then
         let (_,h) ← synthPolyAuto cache fuel sz x val
         return ← finish (← mkAppM `OAI.ThreeMachine.StackCompiler.Poly.volumeNat #[h])
       if polyAutoExprName tp ``Bool then
         return ← finish (← mkAppM `OAI.ThreeMachine.StackCompiler.Poly.volumeBool #[sz,vf])
       if polyAutoExprName tp ``Unit || polyAutoExprName tp ``PUnit then
         return ← finish (← mkAppM `OAI.ThreeMachine.StackCompiler.Poly.volumeUnit #[sz,vf])
       if polyAutoExprName tp ``Prod then
         let a ← mkAppM ``Prod.fst #[val]
         let b ← mkAppM ``Prod.snd #[val]
         let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[a])
         let (_,h') ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[b])
         return ← finish (← mkAppM `OAI.ThreeMachine.StackCompiler.Poly.volumeProd #[vf,h,h'])
       let mut dim? : Option Expr := none
       let mut nm := Name.anonymous
       if polyAutoExprName tp ``Fin then
         dim? := some ts[0]!; nm := `OAI.ThreeMachine.StackCompiler.Poly.volumeFin
       if polyAutoExprName tp ``Finset && polyAutoExprName ts[0]! ``Fin then
         dim? := some ts[0]!.getAppArgs[0]!; nm := `OAI.ThreeMachine.StackCompiler.Poly.volumeFinset
       if polyAutoExprName tp ``ThreeMachine.StackCompiler.Universe then
         dim? := some ts[0]!; nm := `OAI.ThreeMachine.StackCompiler.Poly.volumeUniverse
       if polyAutoExprName tp ``ThreeMachine.StackCompiler.Cardinal then
         dim? := some ts[0]!; nm := `OAI.ThreeMachine.StackCompiler.Poly.volumeCardinal
       if polyAutoExprName tp ``ThreeMachine.StackCompiler.Matrix then
         dim? := some ts[0]!; nm := `OAI.ThreeMachine.StackCompiler.Poly.volumeMatrix
       if polyAutoExprName tp ``ThreeMachine.Algorithm.State && polyAutoExprName ts[0]! ``Fin then
         dim? := some ts[0]!.getAppArgs[0]!; nm := `OAI.ThreeMachine.StackCompiler.Poly.volumeState
       if polyAutoExprName tp ``ThreeMachine.Algorithm.Block then
         if val.getAppFn.isConstOf ``ThreeMachine.Algorithm.Block.mk then
           let bl ← mkAppM ``ThreeMachine.Algorithm.Block.length #[val]
           let bt ← mkAppM ``ThreeMachine.Algorithm.Block.time #[val]
           let (_,hl) ← synthPolyAuto cache fuel sz x bl
           let (_,ht) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[bt])
           return ← finish (← mkAppM ``ThreeMachine.StackCompiler.Poly.volumeBlock #[vf,hl,ht])
       if let .forallE _ dom body _ := (← whnf tp) then
         if polyAutoExprName dom ``Fin && polyAutoExprName body ``Bool then
           dim? := some dom.getAppArgs[0]!; nm := `OAI.ThreeMachine.StackCompiler.Poly.volumeBoolVector
         if polyAutoExprName dom ``Fin then
           if let .forallE _ dom₂ body₂ _ := body then
             if polyAutoExprName dom₂ ``Fin && polyAutoExprName body₂ ``Bool then
               if ← isDefEq dom dom₂ then
                 dim? := some dom.getAppArgs[0]!; nm := `OAI.ThreeMachine.StackCompiler.Poly.volumeMatrix
       if let some dim := dim? then
         let (_,h) ← synthPolyAuto cache fuel sz x dim
         return ← finish (← mkAppM nm #[h,vf])
       if polyAutoExprName tp ``List then
         let (_,hl) ← synthPolyAuto cache fuel sz x (← mkAppM ``List.length #[val])
         let pool ← mkAppM ``ThreeMachine.StackCompiler.Poly.ListPool #[vf]
         let locals := (← getLCtx).decls.toArray.filterMap (fun d => d)
         let xd ← inferType x
         let hv ← withLocalDeclD `q pool fun q => do
           let root ← mkAppM ``Sigma.fst #[q]
           let item ← mkAppM ``Subtype.val #[← mkAppM ``Sigma.snd #[q]]
           let szNew ← mkLambdaFVars #[q] (mkApp sz root)
           let rootFn ← mkLambdaFVars #[q] root
           let mut hs : Array Expr := #[]
           for decl in locals do
             let dt := (← instantiateMVars decl.type).consumeMData
             if polyAutoExprName dt ``ThreeMachine.StackCompiler.Poly then
               if (← withReducible <| isDefEq dt.getAppArgs[0]! xd) then
                 hs := hs.push (← mkAppM ``ThreeMachine.StackCompiler.Poly.precomp #[decl.toExpr,rootFn])
           let (_,pr) ← withPolyFacts hs.toList do
             synthPolyAuto cache fuel szNew q (← mkAppM ``ThreeMachine.StackCompiler.volume #[item])
           return pr
         return ← finish (← mkAppM ``ThreeMachine.StackCompiler.Poly.listVolume #[vf,hl,hv])
       if let .forallE _ dom _ _ := (← whnf tp) then
         if polyAutoExprName dom ``Fin then
           let n := dom.getAppArgs[0]!
           let nf ← mkLambdaFVars #[x] n
           let (_,hn) ← synthPolyAuto cache fuel sz x n
           let pool ← mkAppM ``ThreeMachine.StackCompiler.Poly.FinPool #[nf]
           let locals := (← getLCtx).decls.toArray.filterMap (fun d => d)
           let xd ← inferType x
           let hf ← withLocalDeclD `q pool fun q => do
             let root ← mkAppM ``Sigma.fst #[q]
             let item ← mkAppM ``Sigma.snd #[q]
             let szNew ← mkLambdaFVars #[q] (mkApp sz root)
             let rootFn ← mkLambdaFVars #[q] root
             let mut hs : Array Expr := #[]
             for decl in locals do
               let dt := (← instantiateMVars decl.type).consumeMData
               if polyAutoExprName dt ``ThreeMachine.StackCompiler.Poly then
                 if (← withReducible <| isDefEq dt.getAppArgs[0]! xd) then
                   hs := hs.push (← mkAppM ``ThreeMachine.StackCompiler.Poly.precomp #[decl.toExpr,rootFn])
             let (_,pr) ← withPolyFacts hs.toList do
               synthPolyAuto cache fuel szNew q (← mkAppM ``ThreeMachine.StackCompiler.volume #[mkApp (val.replaceFVar x root) item])
             return pr
           return ← finish (← mkAppM ``ThreeMachine.StackCompiler.Poly.volumeFunction #[vf,hn,hf])
     if let some (h,g,z) ← polyAutoEstimate e x then
       let (_,hs) ← synthPolyAuto cache fuel sz x z
       let proof ← mkAppM ``ThreeMachine.StackCompiler.Poly.reparam #[h,g,hs]
       return (← polyAutoDegree proof,proof)
     if e.getAppFn.isConstOf ``ThreeMachine.StackCompiler.Uniform.time && es.size ≥ 3 then
       let routine := es[es.size-3]!
       let rh := routine.getAppFn.constName?
       let loopNames := #[``ThreeMachine.StackCompiler.Uniform.map,
         ``ThreeMachine.StackCompiler.Uniform.filter, ``ThreeMachine.StackCompiler.Uniform.any,
         ``ThreeMachine.StackCompiler.Uniform.all,
         ``ThreeMachine.StackCompiler.Uniform.filterMap, ``ThreeMachine.StackCompiler.Uniform.firstResult,
         ``ThreeMachine.StackCompiler.Uniform.flatMap, ``ThreeMachine.StackCompiler.Uniform.optionMap]
       if let some k := loopNames.findIdx? (some · == rh) then
         let R := routine.getAppArgs.back!
         unless !(R.containsFVar x.fvarId!) do throwError "dynamic routine"
         let idx := es[es.size-2]!
         let inp := es.back!
         let baseValue ← mkAppM ``Prod.fst #[inp]
         let list ← if k == 7 then mkAppM ``Option.toList #[baseValue] else pure baseValue
         let env ← mkAppM ``Prod.snd #[inp]
         let idxFn ← mkLambdaFVars #[x] idx
         let listFn ← mkLambdaFVars #[x] list
         let envFn ← mkLambdaFVars #[x] env
         let (_,hl) ← synthPolyAuto cache fuel sz x (← mkAppM ``List.length #[list])
         let (_,hx) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[list])
         let (_,he) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[env])
         let ra := routine.getAppArgs
         let dom ← inferType x
         let pool ← mkAppOptM ``ThreeMachine.StackCompiler.Poly.Pool #[some ra[0]!,some dom,some ra[1]!,some idxFn,some listFn]
         let locals := (← getLCtx).decls.toArray.filterMap (fun d => d)
         let (ht,hv) ← withLocalDeclD `q pool fun q => do
           let root ← mkAppM ``Sigma.fst #[q]
           let item ← mkAppM ``Subtype.val #[← mkAppM ``Sigma.snd #[q]]
           let sub (e : Expr) := e.replaceFVar x root
           let sizeNew ← mkLambdaFVars #[q] (mkApp sz root)
           let rootFn ← mkLambdaFVars #[q] root
           let mut hs : Array Expr := #[]
           for decl in locals do
             let dt := (← instantiateMVars decl.type).consumeMData
             if polyAutoExprName dt ``ThreeMachine.StackCompiler.Poly then
               if (← isDefEq dt.getAppArgs[0]! dom) then
                 let p ← mkAppM ``ThreeMachine.StackCompiler.Poly.precomp #[decl.toExpr,rootFn]
                 hs := hs.push p
           let hp ← mkAppM ``ThreeMachine.StackCompiler.Poly.volumePool #[listFn,hx]
           hs := hs.push hp
           withPolyFacts hs.toList do
             let arg ← mkAppM ``Prod.mk #[item,sub env]
             let cost ← mkAppM ``ThreeMachine.StackCompiler.Uniform.time #[R,sub idx,arg]
             let (_,ht) ← synthPolyAuto cache fuel sizeNew q cost
             if k == 0 || k ≥ 4 then
               let f := (← inferType R).getAppArgs.back!
               let out := mkAppN f #[sub idx,arg]
               let (_,hv) ← synthPolyAuto cache fuel sizeNew q (← mkAppM ``ThreeMachine.StackCompiler.volume #[out])
               return (ht,hv)
             else return (ht,mkNatLit 0)
         let nm := #[``ThreeMachine.StackCompiler.Poly.mapTime,
           ``ThreeMachine.StackCompiler.Poly.filterTime, ``ThreeMachine.StackCompiler.Poly.anyTime,
           ``ThreeMachine.StackCompiler.Poly.allTime, ``ThreeMachine.StackCompiler.Poly.filterMapTime,
           ``ThreeMachine.StackCompiler.Poly.firstResultTime, ``ThreeMachine.StackCompiler.Poly.flatMapTime, ``ThreeMachine.StackCompiler.Poly.optionMapTime][k]!
         let optionFn ← mkLambdaFVars #[x] baseValue
         let hx' ← if k == 7 then do
             let (_,h) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[baseValue])
             pure h
           else pure hx
         let pre := if k == 7 then
             #[some ra[0]!,some dom,some sz,some ra[1]!,some ra[2]!,some ra[3]!,some ra[4]!,some ra[5]!,some ra[6]!,
               some idxFn,some envFn,some optionFn,some ra[7]!,some R,none,none,none,none]
           else if k == 0 || k ≥ 4 then
             #[some ra[0]!,some dom,some sz,some ra[1]!,some ra[2]!,some ra[3]!,some ra[4]!,some ra[5]!,some ra[6]!,
               some idxFn,some listFn,some envFn,some ra[7]!,some R,none,none,none,none,none]
           else
             #[some ra[0]!,some dom,some sz,some ra[1]!,some ra[2]!,some ra[3]!,some ra[4]!,
               some idxFn,some listFn,some envFn,some ra[5]!,some R,none,none,none,none]
         let args := pre ++ (if k == 7 then #[some ht,some hx',some he] else #[some hl,some ht,some hx,some he])
         let args := if k == 0 || k ≥ 4 then args.push (some hv) else args
         let proof ← mkAppOptM nm args
         return (← polyAutoDegree proof,proof)
     if e.isApp && (← isDefEq (← inferType e) (mkConst ``Nat)) then
       let f := e.appFn!
       let a := e.appArg!
       let tp ← withReducible <| whnf (← inferType f)
       if let .forallE _ dom body _ := tp then
         if polyAutoExprName dom ``Fin && polyAutoExprName body ``Nat then
           let af ← mkLambdaFVars #[x] a
           let (_,hf) ← synthPolyAuto cache fuel sz x (← mkAppM ``ThreeMachine.StackCompiler.volume #[f])
           let proof ← mkAppM ``ThreeMachine.StackCompiler.Poly.natFunctionApply #[af,hf]
           return (← polyAutoDegree proof,proof)
     if (polyAutoCostHead e).isSome then
       if let some (rhs,p) ← polyAutoRule e then
         let (_,h) ← synthPolyAuto cache fuel sz x rhs
         let p ← mkLambdaFVars #[x] p
         let proof ← mkAppM ``ThreeMachine.StackCompiler.Poly.of_le #[p,h]
         return (← polyAutoDegree proof,proof)
       let pos := if e.getAppFn.isConstOf ``ThreeMachine.StackCompiler.Uniform.time then es.size-3 else es.size-2
       let r := es[pos]!
       if let some r' ← unfoldDefinition? r then
         let r' ← zetaReduce r' (zetaDelta := false)
         let r' ← withReducible <| whnf r'
         let args := es.set! pos r'.headBeta
         return ← synthPolyAuto cache fuel sz x (mkAppN e.getAppFn args)
     throwError "poly_auto: no bound for {e}"
  )
  let (d,p) := result
  let d ← instantiateMVars d
  let d ← if d.hasFVar then pure d else whnf d
  let p ← instantiateMVars p
  let p ← if p.approxDepth > 15 then do
      let tp := (← inferType p).consumeMData
      let args := tp.getAppArgs
      let tp := mkAppN tp.getAppFn (args.set! 3 d)
      mkAuxTheorem tp p
    else pure p
  let result := (d,p)
  cache.modify (·.insert key result)
  return result

open Lean Meta Elab Tactic in
elab "poly_auto" : tactic => do
  let goal ← getMainGoal
  goal.withContext do
    let tp := (← instantiateMVars (← goal.getType)).consumeMData
    unless polyAutoExprName tp ``ThreeMachine.StackCompiler.Poly do
      throwError "poly_auto expects Poly, got {tp}"
    let args := tp.getAppArgs
    let sz := args[1]!
    let fn := args[2]!
    let wanted := args[3]!
    let fty ← inferType fn
    forallTelescopeReducing fty fun xs _ => do
      unless xs.size == 1 do throwError "poly_auto expects unary function"
      let body := (mkApp fn xs[0]!).headBeta.consumeMData
      let cache ← IO.mkRef ({} : Std.HashMap (Expr × Expr × Expr) (Expr × Expr))
      let (d,h) ← synthPolyAuto cache 1000 sz xs[0]! body
      let le ← mkFreshExprMVar (← mkAppM ``LE.le #[d,wanted])
      let proof ← mkAppM ``ThreeMachine.StackCompiler.Poly.lift #[h,le]
      goal.assign proof
      replaceMainGoal [le.mvarId!]
  evalTactic (← `(tactic| first | exact Nat.le_refl _ | assumption | omega | decide))
end

end OAI