GCC Code Coverage Report
Directory: . Exec Total Coverage
File: src/theory/uf/proof_checker.cpp Lines: 76 115 66.1 %
Date: 2021-09-29 Branches: 128 562 22.8 %

Line Exec Source
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/******************************************************************************
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 * Top contributors (to current version):
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 *   Haniel Barbosa, Andrew Reynolds, Aina Niemetz
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 *
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 * This file is part of the cvc5 project.
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 *
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 * Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
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 * in the top-level source directory and their institutional affiliations.
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 * All rights reserved.  See the file COPYING in the top-level source
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 * directory for licensing information.
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 * ****************************************************************************
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 *
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 * Implementation of equality proof checker.
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 */
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#include "theory/uf/proof_checker.h"
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#include "theory/uf/theory_uf_rewriter.h"
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using namespace cvc5::kind;
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namespace cvc5 {
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namespace theory {
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namespace uf {
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143
void UfProofRuleChecker::registerTo(ProofChecker* pc)
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{
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  // add checkers
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  pc->registerChecker(PfRule::REFL, this);
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  pc->registerChecker(PfRule::SYMM, this);
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  pc->registerChecker(PfRule::TRANS, this);
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  pc->registerChecker(PfRule::CONG, this);
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  pc->registerChecker(PfRule::TRUE_INTRO, this);
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  pc->registerChecker(PfRule::TRUE_ELIM, this);
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  pc->registerChecker(PfRule::FALSE_INTRO, this);
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  pc->registerChecker(PfRule::FALSE_ELIM, this);
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  pc->registerChecker(PfRule::HO_CONG, this);
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  pc->registerChecker(PfRule::HO_APP_ENCODE, this);
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}
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12114
Node UfProofRuleChecker::checkInternal(PfRule id,
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                                       const std::vector<Node>& children,
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                                       const std::vector<Node>& args)
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{
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  // compute what was proven
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12114
  if (id == PfRule::REFL)
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  {
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300
    Assert(children.empty());
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    Assert(args.size() == 1);
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    return args[0].eqNode(args[0]);
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  }
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11814
  else if (id == PfRule::SYMM)
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  {
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10957
    Assert(children.size() == 1);
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10957
    Assert(args.empty());
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10957
    bool polarity = children[0].getKind() != NOT;
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21914
    Node eqp = polarity ? children[0] : children[0][0];
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10957
    if (eqp.getKind() != EQUAL)
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    {
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      // not a (dis)equality
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      return Node::null();
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    }
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21914
    Node conc = eqp[1].eqNode(eqp[0]);
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10957
    return polarity ? conc : conc.notNode();
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  }
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  else if (id == PfRule::TRANS)
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  {
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    Assert(children.size() > 0);
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    Assert(args.empty());
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    Node first;
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    Node curr;
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    for (size_t i = 0, nchild = children.size(); i < nchild; i++)
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    {
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      Node eqp = children[i];
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      if (eqp.getKind() != EQUAL)
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      {
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        return Node::null();
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      }
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      if (first.isNull())
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      {
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        first = eqp[0];
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      }
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      else if (eqp[0] != curr)
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      {
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        return Node::null();
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      }
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      curr = eqp[1];
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    }
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    return first.eqNode(curr);
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  }
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  else if (id == PfRule::CONG)
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  {
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    Assert(children.size() > 0);
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    Assert(args.size() >= 1 && args.size() <= 2);
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    // We do congruence over builtin kinds using operatorToKind
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    std::vector<Node> lchildren;
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    std::vector<Node> rchildren;
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    // get the kind encoded as args[0]
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    Kind k;
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    if (!getKind(args[0], k))
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    {
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      return Node::null();
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    }
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    if (k == kind::UNDEFINED_KIND)
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    {
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      return Node::null();
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    }
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436
    Trace("uf-pfcheck") << "congruence for " << args[0] << " uses kind " << k
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                        << ", metakind=" << kind::metaKindOf(k) << std::endl;
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    if (kind::metaKindOf(k) == kind::metakind::PARAMETERIZED)
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    {
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      if (args.size() <= 1)
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      {
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        return Node::null();
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      }
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      // parameterized kinds require the operator
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      lchildren.push_back(args[1]);
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      rchildren.push_back(args[1]);
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    }
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    else if (args.size() > 1)
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    {
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      return Node::null();
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    }
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    for (size_t i = 0, nchild = children.size(); i < nchild; i++)
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    {
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      Node eqp = children[i];
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742
      if (eqp.getKind() != EQUAL)
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      {
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        return Node::null();
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      }
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742
      lchildren.push_back(eqp[0]);
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      rchildren.push_back(eqp[1]);
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    }
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    NodeManager* nm = NodeManager::currentNM();
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    Node l = nm->mkNode(k, lchildren);
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    Node r = nm->mkNode(k, rchildren);
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    return l.eqNode(r);
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  }
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  else if (id == PfRule::TRUE_INTRO)
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  {
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    Assert(children.size() == 1);
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    Assert(args.empty());
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    Node trueNode = NodeManager::currentNM()->mkConst(true);
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    return children[0].eqNode(trueNode);
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  }
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  else if (id == PfRule::TRUE_ELIM)
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  {
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    Assert(children.size() == 1);
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    Assert(args.empty());
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    if (children[0].getKind() != EQUAL || !children[0][1].isConst()
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        || !children[0][1].getConst<bool>())
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    {
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      return Node::null();
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    }
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    return children[0][0];
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  }
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  else if (id == PfRule::FALSE_INTRO)
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  {
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    Assert(children.size() == 1);
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    Assert(args.empty());
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    if (children[0].getKind() != kind::NOT)
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    {
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      return Node::null();
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    }
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    Node falseNode = NodeManager::currentNM()->mkConst(false);
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    return children[0][0].eqNode(falseNode);
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  }
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  else if (id == PfRule::FALSE_ELIM)
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  {
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    Assert(children.size() == 1);
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    Assert(args.empty());
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    if (children[0].getKind() != EQUAL || !children[0][1].isConst()
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        || children[0][1].getConst<bool>())
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    {
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      return Node::null();
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    }
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    return children[0][0].notNode();
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  }
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  if (id == PfRule::HO_CONG)
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  {
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    Assert(children.size() > 0);
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    std::vector<Node> lchildren;
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    std::vector<Node> rchildren;
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    for (size_t i = 0, nchild = children.size(); i < nchild; ++i)
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    {
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      Node eqp = children[i];
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      if (eqp.getKind() != EQUAL)
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      {
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        return Node::null();
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      }
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      lchildren.push_back(eqp[0]);
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      rchildren.push_back(eqp[1]);
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    }
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    NodeManager* nm = NodeManager::currentNM();
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    Node l = nm->mkNode(kind::APPLY_UF, lchildren);
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    Node r = nm->mkNode(kind::APPLY_UF, rchildren);
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    return l.eqNode(r);
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  }
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  else if (id == PfRule::HO_APP_ENCODE)
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  {
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    Assert(args.size() == 1);
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    Node ret = TheoryUfRewriter::getHoApplyForApplyUf(args[0]);
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    return args[0].eqNode(ret);
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  }
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  // no rule
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  return Node::null();
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}
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}  // namespace uf
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}  // namespace theory
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}  // namespace cvc5