From 4fcc4d07aea07ca7fda1f5eb8bfa87985a8c173a Mon Sep 17 00:00:00 2001
From: Nikolaj Bjorner <nbjorner@microsoft.com>
Date: Tue, 14 May 2019 19:05:40 +0200
Subject: [PATCH] fix #2277 fix #2221

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
---
 src/api/c++/z3++.h                     |  2 +
 src/ast/ast.cpp                        | 43 ++++++++++++----
 src/ast/ast.h                          |  7 +++
 src/ast/normal_forms/defined_names.cpp |  8 +--
 src/ast/normal_forms/nnf.cpp           | 19 ++-----
 src/smt/smt_internalizer.cpp           | 12 +++--
 src/smt/smt_model_generator.cpp        |  8 +--
 src/smt/theory_array.cpp               | 10 ++--
 src/smt/theory_array.h                 |  1 +
 src/smt/theory_array_base.cpp          | 71 +++++++++++++++++++++++++-
 src/smt/theory_array_base.h            |  5 ++
 src/smt/theory_lra.cpp                 |  2 +-
 12 files changed, 139 insertions(+), 49 deletions(-)

diff --git a/src/api/c++/z3++.h b/src/api/c++/z3++.h
index edbc11e7d..60d5afecd 100644
--- a/src/api/c++/z3++.h
+++ b/src/api/c++/z3++.h
@@ -1573,12 +1573,14 @@ namespace z3 {
         else {
             r = Z3_mk_fpa_abs(a.ctx(), a); 
         }
+        a.check_error();
         return expr(a.ctx(), r); 
     }
     inline expr sqrt(expr const & a, expr const& rm) {
         check_context(a, rm);
         assert(a.is_fpa());
         Z3_ast r = Z3_mk_fpa_sqrt(a.ctx(), rm, a);
+        a.check_error();
         return expr(a.ctx(), r);
     }
     inline expr operator~(expr const & a) { Z3_ast r = Z3_mk_bvnot(a.ctx(), a); return expr(a.ctx(), r); }
diff --git a/src/ast/ast.cpp b/src/ast/ast.cpp
index e358c5fe1..4b79edf7f 100644
--- a/src/ast/ast.cpp
+++ b/src/ast/ast.cpp
@@ -269,7 +269,8 @@ func_decl_info::func_decl_info(family_id family_id, decl_kind k, unsigned num_pa
     m_pairwise(false),
     m_injective(false),
     m_idempotent(false),
-    m_skolem(false) {
+    m_skolem(false),
+    m_lambda(false) {
 }
 
 bool func_decl_info::operator==(func_decl_info const & info) const {
@@ -281,20 +282,22 @@ bool func_decl_info::operator==(func_decl_info const & info) const {
         m_chainable == info.m_chainable &&
         m_pairwise == info.m_pairwise &&
         m_injective == info.m_injective &&
-        m_skolem == info.m_skolem;
+        m_skolem == info.m_skolem &&
+        m_lambda == info.m_lambda;
 }
 
 std::ostream & operator<<(std::ostream & out, func_decl_info const & info) {
     operator<<(out, static_cast<decl_info const&>(info));
-    out << " :left-assoc " << info.is_left_associative();
-    out << " :right-assoc " << info.is_right_associative();
-    out << " :flat-associative " << info.is_flat_associative();
-    out << " :commutative " << info.is_commutative();
-    out << " :chainable " << info.is_chainable();
-    out << " :pairwise " << info.is_pairwise();
-    out << " :injective " << info.is_injective();
-    out << " :idempotent " << info.is_idempotent();
-    out << " :skolem " << info.is_skolem();
+    if (info.is_left_associative()) out << " :left-assoc ";
+    if (info.is_right_associative()) out << " :right-assoc ";
+    if (info.is_flat_associative()) out << " :flat-associative ";
+    if (info.is_commutative()) out << " :commutative ";
+    if (info.is_chainable()) out << " :chainable ";
+    if (info.is_pairwise()) out << " :pairwise ";
+    if (info.is_injective()) out << " :injective ";
+    if (info.is_idempotent()) out << " :idempotent ";
+    if (info.is_skolem()) out << " :skolem ";
+    if (info.is_lambda()) out << " :lambda ";
     return out;
 }
 
@@ -1713,6 +1716,20 @@ bool ast_manager::are_distinct(expr* a, expr* b) const {
     return false;
 }
 
+void ast_manager::add_lambda_def(func_decl* f, quantifier* q) {
+    m_lambda_defs.insert(f, q);
+    f->get_info()->set_lambda(true);
+    inc_ref(q);
+}
+
+quantifier* ast_manager::is_lambda_def(func_decl* f) {
+    if (f->get_info() && f->get_info()->is_lambda()) {
+        return m_lambda_defs[f];
+    }
+    return nullptr;
+}
+
+
 func_decl* ast_manager::get_rec_fun_decl(quantifier* q) const {
     SASSERT(is_rec_fun_def(q)); 
     return to_app(to_app(q->get_pattern(0))->get_arg(0))->get_decl(); 
@@ -1901,6 +1918,10 @@ void ast_manager::delete_node(ast * n) {
             func_decl* f = to_func_decl(n);
             if (f->m_info != nullptr && !m_debug_ref_count) {
                 func_decl_info * info = f->get_info();
+                if (info->is_lambda()) {
+                    push_dec_ref(m_lambda_defs[f]);
+                    m_lambda_defs.remove(f);
+                }
                 info->del_eh(*this);
                 dealloc(info);
             }
diff --git a/src/ast/ast.h b/src/ast/ast.h
index 5ba3a900e..e654ef1d6 100644
--- a/src/ast/ast.h
+++ b/src/ast/ast.h
@@ -398,6 +398,7 @@ struct func_decl_info : public decl_info {
     bool m_injective:1;
     bool m_idempotent:1;
     bool m_skolem:1;
+    bool m_lambda:1;
 
     func_decl_info(family_id family_id = null_family_id, decl_kind k = null_decl_kind, unsigned num_parameters = 0, parameter const * parameters = nullptr);
     ~func_decl_info() {}
@@ -412,6 +413,7 @@ struct func_decl_info : public decl_info {
     bool is_injective() const { return m_injective; }
     bool is_idempotent() const { return m_idempotent; }
     bool is_skolem() const { return m_skolem; }
+    bool is_lambda() const { return m_lambda; }
 
     void set_associative(bool flag = true) { m_left_assoc = flag; m_right_assoc = flag; }
     void set_left_associative(bool flag = true) { m_left_assoc = flag; }
@@ -423,6 +425,7 @@ struct func_decl_info : public decl_info {
     void set_injective(bool flag = true) { m_injective = flag; }
     void set_idempotent(bool flag = true) { m_idempotent = flag; }
     void set_skolem(bool flag = true) { m_skolem = flag; }
+    void set_lambda(bool flag = true) { m_lambda = flag; }
 
     bool operator==(func_decl_info const & info) const;
 
@@ -641,6 +644,7 @@ public:
     bool is_pairwise() const { return get_info() != nullptr && get_info()->is_pairwise(); }
     bool is_injective() const { return get_info() != nullptr && get_info()->is_injective(); }
     bool is_skolem() const { return get_info() != nullptr && get_info()->is_skolem(); }
+    bool is_lambda() const { return get_info() != nullptr && get_info()->is_lambda(); }
     bool is_idempotent() const { return get_info() != nullptr && get_info()->is_idempotent(); }
     unsigned get_arity() const { return m_arity; }
     sort * get_domain(unsigned idx) const { SASSERT(idx < get_arity()); return m_domain[idx]; }
@@ -1522,6 +1526,7 @@ protected:
     family_id                 m_user_sort_family_id;
     family_id                 m_arith_family_id;
     ast_table                 m_ast_table;
+    obj_map<func_decl, quantifier*> m_lambda_defs;
     id_gen                    m_expr_id_gen;
     id_gen                    m_decl_id_gen;
     sort *                    m_bool_sort;
@@ -1651,6 +1656,8 @@ public:
     
     bool is_rec_fun_def(quantifier* q) const { return q->get_qid() == m_rec_fun; }
     bool is_lambda_def(quantifier* q) const { return q->get_qid() == m_lambda_def; }
+    void add_lambda_def(func_decl* f, quantifier* q);
+    quantifier* is_lambda_def(func_decl* f);
     func_decl* get_rec_fun_decl(quantifier* q) const;
     
     symbol const& rec_fun_qid() const { return m_rec_fun; }
diff --git a/src/ast/normal_forms/defined_names.cpp b/src/ast/normal_forms/defined_names.cpp
index 0dcdd9597..1a5ffb4da 100644
--- a/src/ast/normal_forms/defined_names.cpp
+++ b/src/ast/normal_forms/defined_names.cpp
@@ -122,9 +122,9 @@ app * defined_names::impl::gen_name(expr * e, sort_ref_buffer & var_sorts, buffe
     sort * range = m.get_sort(e);
     func_decl * new_skolem_decl = m.mk_fresh_func_decl(m_z3name, symbol::null, domain.size(), domain.c_ptr(), range);
     app * n = m.mk_app(new_skolem_decl, new_args.size(), new_args.c_ptr());
-    TRACE("mk_definition_bug", tout << "gen_name: " << mk_ismt2_pp(n, m) << "\n";
-          for (unsigned i = 0; i < var_sorts.size(); i++) tout << mk_pp(var_sorts[i], m) << " ";
-          tout << "\n";);
+    if (is_lambda(e)) {
+        m.add_lambda_def(new_skolem_decl, to_quantifier(e));
+    }
     return n;
 }
 
@@ -203,7 +203,7 @@ void defined_names::impl::mk_definition(expr * e, app * n, sort_ref_buffer & var
         // NB. The pattern is incomplete.
         // consider store(a, i, v) == \lambda j . if i = j then v else a[j]
         // the instantiation rules for store(a, i, v) are:
-        //     sotre(a, i, v)[j] = if i = j then v else a[j] with patterns {a[j], store(a, i, v)} { store(a, i, v)[j] }
+        //     store(a, i, v)[j] = if i = j then v else a[j] with patterns {a[j], store(a, i, v)} { store(a, i, v)[j] }
         // The first pattern is not included.
         // TBD use a model-based scheme for exracting instantiations instead of
         // using multi-patterns.
diff --git a/src/ast/normal_forms/nnf.cpp b/src/ast/normal_forms/nnf.cpp
index c03ff1d0f..26ffc1709 100644
--- a/src/ast/normal_forms/nnf.cpp
+++ b/src/ast/normal_forms/nnf.cpp
@@ -27,7 +27,6 @@ Notes:
 #include "ast/act_cache.h"
 #include "ast/rewriter/var_subst.h"
 #include "ast/normal_forms/name_exprs.h"
-
 #include "ast/ast_smt2_pp.h"
 
 /**
@@ -754,8 +753,7 @@ struct nnf::imp {
         if (fr.m_i == 0) {
             fr.m_i = 1;
             if (is_lambda(q)) {
-                if (!visit(q->get_expr(), fr.m_pol, true))
-                    return false;
+                // skip
             }
             else if (is_forall(q) == fr.m_pol) {
                 if (!visit(q->get_expr(), fr.m_pol, true))
@@ -769,19 +767,9 @@ struct nnf::imp {
         }
 
         if (is_lambda(q)) {
-            expr * new_expr = m_result_stack.back();
-            quantifier * new_q = m.update_quantifier(q, new_expr);
-            proof * new_q_pr   = nullptr;
+            m_result_stack.push_back(q);
             if (proofs_enabled()) {
-                // proof * new_expr_pr = m_result_pr_stack.back();
-                new_q_pr = m.mk_rewrite(q, new_q);  // TBD use new_expr_pr
-            }
-                                                      
-            m_result_stack.pop_back();
-            m_result_stack.push_back(new_q);
-            if (proofs_enabled()) {
-                m_result_pr_stack.pop_back();
-                m_result_pr_stack.push_back(new_q_pr);
+                m_result_pr_stack.push_back(nullptr);
                 SASSERT(m_result_stack.size() == m_result_pr_stack.size());
             }
             return true;
@@ -949,7 +937,6 @@ void nnf::get_param_descrs(param_descrs & r) {
     imp::get_param_descrs(r);
 }
 
-
 void nnf::reset() {
     m_imp->reset();
 }
diff --git a/src/smt/smt_internalizer.cpp b/src/smt/smt_internalizer.cpp
index eb2673da9..ac4f2e1b5 100644
--- a/src/smt/smt_internalizer.cpp
+++ b/src/smt/smt_internalizer.cpp
@@ -535,14 +535,14 @@ namespace smt {
     }
 
     void context::internalize_lambda(quantifier * q) {
-        UNREACHABLE();
-
 #if 0
+        UNREACHABLE();
+#else
         TRACE("internalize_quantifier", tout << mk_pp(q, m_manager) << "\n";);
         SASSERT(is_lambda(q));
         app_ref lam_name(m_manager.mk_fresh_const("lambda", m_manager.get_sort(q)), m_manager);
         enode * e = mk_enode(lam_name, true, false, false);
-        expr_ref eq(m_manager), lam_app(m_manager);
+        app_ref eq(m_manager), lam_app(m_manager);
         expr_ref_vector vars(m_manager);
         vars.push_back(lam_name);
         unsigned sz = q->get_num_decls();
@@ -553,9 +553,11 @@ namespace smt {
         lam_app = autil.mk_select(vars.size(), vars.c_ptr());
         eq = m_manager.mk_eq(lam_app, q->get_expr());
         quantifier_ref fa(m_manager);
-        expr * patterns[1] = { m_manager.mk_pattern(lam_name) };
+        expr * patterns[1] = { m_manager.mk_pattern(lam_app) };
         fa = m_manager.mk_forall(sz, q->get_decl_sorts(), q->get_decl_names(), eq, 0, m_manager.lambda_def_qid(), symbol::null, 1, patterns);
         internalize_quantifier(fa, true);
+        if (!e_internalized(lam_name)) internalize_uninterpreted(lam_name);
+        m_app2enode.setx(q->get_id(), get_enode(lam_name), nullptr);
 #endif
     }
 
@@ -938,7 +940,7 @@ namespace smt {
             e->mark_as_interpreted();
         TRACE("mk_var_bug", tout << "mk_enode: " << id << "\n";);
         TRACE("generation", tout << "mk_enode: " << id << " " << generation << "\n";);
-        m_app2enode.setx(id, e, 0);
+        m_app2enode.setx(id, e, nullptr);
         m_e_internalized_stack.push_back(n);
         m_trail_stack.push_back(&m_mk_enode_trail);
         m_enodes.push_back(e);
diff --git a/src/smt/smt_model_generator.cpp b/src/smt/smt_model_generator.cpp
index 767b9e06e..43c89d074 100644
--- a/src/smt/smt_model_generator.cpp
+++ b/src/smt/smt_model_generator.cpp
@@ -272,9 +272,7 @@ namespace smt {
         }
 
         // traverse all enodes that are associated with fresh values...
-        unsigned sz = roots.size();
-        for (unsigned i = 0; i < sz; i++) {
-            enode * r     = roots[i];
+        for (enode* r : roots) {
             model_value_proc * proc = root2proc[r];
             SASSERT(proc);
             if (!proc->is_fresh())
@@ -282,9 +280,7 @@ namespace smt {
             process_source(source(r), roots, root2proc, colors, already_traversed, todo, sorted_sources);
         }
 
-        sz = roots.size();
-        for (unsigned i = 0; i < sz; i++) {
-            enode * r     = roots[i];
+        for (enode * r : roots) {
             process_source(source(r), roots, root2proc, colors, already_traversed, todo, sorted_sources);
         }
     }
diff --git a/src/smt/theory_array.cpp b/src/smt/theory_array.cpp
index d9e0b1995..f3420df45 100644
--- a/src/smt/theory_array.cpp
+++ b/src/smt/theory_array.cpp
@@ -230,6 +230,7 @@ namespace smt {
             m_stats.m_num_extensionality++;
     }
 
+
     bool theory_array::internalize_atom(app * atom, bool) {
         return internalize_term(atom);
     }
@@ -297,12 +298,11 @@ namespace smt {
 
     void theory_array::new_eq_eh(theory_var v1, theory_var v2) {
         m_find.merge(v1, v2);
-#if 0
-        if (is_lambda(get_enode(v1)->get_owner()) ||
-            is_lambda(get_enode(v2)->get_owner())) {
-            instantiate_extensionality(get_enode(v1), get_enode(v2));       
+        enode* n1 = get_enode(v1), *n2 = get_enode(v2);
+        if (n1->get_owner()->get_decl()->is_lambda() ||
+            n2->get_owner()->get_decl()->is_lambda()) {
+            assert_congruent(n1, n2);
         }
-#endif
     }
 
     void theory_array::new_diseq_eh(theory_var v1, theory_var v2) {
diff --git a/src/smt/theory_array.h b/src/smt/theory_array.h
index 26d59c7bf..187978012 100644
--- a/src/smt/theory_array.h
+++ b/src/smt/theory_array.h
@@ -88,6 +88,7 @@ namespace smt {
         bool instantiate_axiom2b(enode * select, enode * store);
         void instantiate_axiom1(enode * store);
         void instantiate_extensionality(enode * a1, enode * a2);
+        void instantiate_congruent(enode * a1, enode * a2);
         bool instantiate_axiom2b_for(theory_var v);
         
         virtual final_check_status assert_delayed_axioms();
diff --git a/src/smt/theory_array_base.cpp b/src/smt/theory_array_base.cpp
index bb3ed9992..6d9969e8d 100644
--- a/src/smt/theory_array_base.cpp
+++ b/src/smt/theory_array_base.cpp
@@ -300,6 +300,20 @@ namespace smt {
         m_extensionality_todo.push_back(std::make_pair(n1, n2));         
         return true;
     }
+
+    void theory_array_base::assert_congruent(enode * a1, enode * a2) {
+        TRACE("array", tout << "congruent: #" << a1->get_owner_id() << " #" << a2->get_owner_id() << "\n";);
+        SASSERT(is_array_sort(a1));
+        SASSERT(is_array_sort(a2));
+        context & ctx = get_context();
+        if (a1->get_owner_id() > a2->get_owner_id())
+            std::swap(a1, a2);
+        enode * nodes[2] = { a1, a2 };
+        if (!ctx.add_fingerprint(this, 1, 2, nodes))
+            return; // axiom was already instantiated
+        m_congruent_todo.push_back(std::make_pair(a1, a2));         
+    }
+
    
     void theory_array_base::assert_extensionality_core(enode * n1, enode * n2) {
         app * e1        = n1->get_owner();
@@ -338,8 +352,59 @@ namespace smt {
         if (m.has_trace_stream()) m.trace_stream() << "[end-of-instance]\n";
     }
 
+    /**
+       \brief assert n1 = n2 => forall vars . (n1 vars) = (n2 vars)
+     */
+    void theory_array_base::assert_congruent_core(enode * n1, enode * n2) {
+        app * e1        = n1->get_owner();
+        app * e2        = n2->get_owner();
+        context & ctx   = get_context();
+        ast_manager & m = get_manager();
+        sort* s         = m.get_sort(e1);
+        unsigned dimension = get_array_arity(s);
+        literal n1_eq_n2 = mk_eq(e1, e2, true);
+        ctx.mark_as_relevant(n1_eq_n2);
+        expr_ref_vector args1(m), args2(m);
+        expr_ref f1 = instantiate_lambda(e1);
+        expr_ref f2 = instantiate_lambda(e2);
+        args1.push_back(f1);
+        args2.push_back(f2);
+        svector<symbol> names;
+        sort_ref_vector sorts(m);
+        for (unsigned i = 0; i < dimension; i++) {
+            sort * srt = get_array_domain(s, i);
+            sorts.push_back(srt);
+            names.push_back(symbol(i));
+            expr * k = m.mk_var(dimension - i - 1, srt);
+            args1.push_back(k);
+            args2.push_back(k);            
+        }
+        expr * sel1 = mk_select(dimension+1, args1.c_ptr());
+        expr * sel2 = mk_select(dimension+1, args2.c_ptr());
+        expr * eq = m.mk_eq(sel1, sel2);
+        expr_ref q(m.mk_forall(dimension, sorts.c_ptr(), names.c_ptr(), eq), m);
+        ctx.get_rewriter()(q);
+        if (!ctx.b_internalized(q)) {
+            ctx.internalize(q, true);
+        }
+        literal fa_eq = ctx.get_literal(q);
+        ctx.mark_as_relevant(fa_eq);
+        assert_axiom(~n1_eq_n2, fa_eq);
+    }
+
+    expr_ref theory_array_base::instantiate_lambda(app* e) {
+        ast_manager& m = get_manager();
+        quantifier * q = m.is_lambda_def(e->get_decl());
+        expr_ref f(e, m);
+        if (q) {
+            var_subst sub(m, false);
+            f = sub(q, e->get_num_args(), e->get_args());
+        }
+        return f;
+    }
+
     bool theory_array_base::can_propagate() {
-        return !m_axiom1_todo.empty() || !m_axiom2_todo.empty() || !m_extensionality_todo.empty();
+        return !m_axiom1_todo.empty() || !m_axiom2_todo.empty() || !m_extensionality_todo.empty() || !m_congruent_todo.empty();
     }
 
     void theory_array_base::propagate() {
@@ -352,7 +417,10 @@ namespace smt {
             m_axiom2_todo.reset();
             for (unsigned i = 0; i < m_extensionality_todo.size(); i++)
                 assert_extensionality_core(m_extensionality_todo[i].first, m_extensionality_todo[i].second);
+            for (unsigned i = 0; i < m_congruent_todo.size(); i++)
+                assert_congruent_core(m_congruent_todo[i].first, m_congruent_todo[i].second);
             m_extensionality_todo.reset();
+            m_congruent_todo.reset();
         }
     }
 
@@ -522,6 +590,7 @@ namespace smt {
         m_axiom1_todo.reset();
         m_axiom2_todo.reset();
         m_extensionality_todo.reset();
+        m_congruent_todo.reset();
     }
 
 
diff --git a/src/smt/theory_array_base.h b/src/smt/theory_array_base.h
index bf35bdd1b..75de7d7e9 100644
--- a/src/smt/theory_array_base.h
+++ b/src/smt/theory_array_base.h
@@ -66,6 +66,7 @@ namespace smt {
         ptr_vector<enode>                   m_axiom1_todo;
         enode_pair_vector                   m_axiom2_todo;
         enode_pair_vector                   m_extensionality_todo;
+        enode_pair_vector                   m_congruent_todo;
         scoped_ptr<theory_array_bapa>       m_bapa;
 
         void assert_axiom(unsigned num_lits, literal * lits);
@@ -79,6 +80,10 @@ namespace smt {
         void assert_extensionality_core(enode * a1, enode * a2);
         bool assert_extensionality(enode * a1, enode * a2);
 
+        expr_ref instantiate_lambda(app* e);
+        void assert_congruent_core(enode * a1, enode * a2);
+        void assert_congruent(enode * a1, enode * a2);
+
         // --------------------------------------------------
         // Array sort -> extensionality skolems
         // 
diff --git a/src/smt/theory_lra.cpp b/src/smt/theory_lra.cpp
index 11a9fa6f7..77815ceda 100644
--- a/src/smt/theory_lra.cpp
+++ b/src/smt/theory_lra.cpp
@@ -3429,7 +3429,7 @@ public:
     }
 
     app_ref mk_obj(theory_var v) {
-        lp::var_index vi = m_theory_var2var_index[v];
+        lp::var_index vi = get_var_index(v);
         bool is_int = a.is_int(get_enode(v)->get_owner());
         if (m_solver->is_term(vi)) {           
             return mk_term(m_solver->get_term(vi), is_int);