diff --git a/src/ast/occurs.cpp b/src/ast/occurs.cpp
index 9ddb2fa56..21e7f5906 100644
--- a/src/ast/occurs.cpp
+++ b/src/ast/occurs.cpp
@@ -26,7 +26,7 @@ Revision History:
 //
 // -----------------------------------
 
-namespace occurs_namespace {
+namespace {
     struct found {}; 
     
     struct proc {
@@ -49,27 +49,26 @@ namespace occurs_namespace {
         void operator()(quantifier const * n) { }
     };
 
-
-};
+}
 
 // Return true if n1 occurs in n2
 bool occurs(expr * n1, expr * n2) {
-    occurs_namespace::proc p(n1);
+    proc p(n1);
     try {
         quick_for_each_expr(p, n2);
     }
-    catch (const occurs_namespace::found &) {
+    catch (const found &) {
         return true;
     }
     return false;
 }
 
 bool occurs(func_decl * d, expr * n) {
-    occurs_namespace::decl_proc p(d);
+    decl_proc p(d);
     try {
         quick_for_each_expr(p, n);
     }
-    catch (const occurs_namespace::found &) {
+    catch (const found &) {
         return true;
     }
     return false;
diff --git a/src/ast/well_sorted.cpp b/src/ast/well_sorted.cpp
index b300b9ac3..0516989e0 100644
--- a/src/ast/well_sorted.cpp
+++ b/src/ast/well_sorted.cpp
@@ -25,6 +25,8 @@ Revision History:
 #include "util/warning.h"
 #include "ast/ast_smt2_pp.h"
 
+namespace {
+
 struct well_sorted_proc {
     ast_manager & m_manager;
     bool          m_error;
@@ -76,6 +78,8 @@ struct well_sorted_proc {
     }
 };
 
+}
+
 bool is_well_sorted(ast_manager const & m, expr * n) {
     well_sorted_proc p(const_cast<ast_manager&>(m));
     for_each_expr(p, n);
diff --git a/src/sat/CMakeLists.txt b/src/sat/CMakeLists.txt
index c80284b85..649bbb22e 100644
--- a/src/sat/CMakeLists.txt
+++ b/src/sat/CMakeLists.txt
@@ -20,7 +20,6 @@ z3_add_component(sat
     sat_elim_eqs.cpp
     sat_elim_vars.cpp
     sat_bcd.cpp
-    sat_iff3_finder.cpp
     sat_integrity_checker.cpp
     sat_local_search.cpp
     sat_lookahead.cpp
diff --git a/src/sat/dimacs.cpp b/src/sat/dimacs.cpp
index 970e682b3..ea8789958 100644
--- a/src/sat/dimacs.cpp
+++ b/src/sat/dimacs.cpp
@@ -21,6 +21,7 @@ Revision History:
 #undef min
 #include "sat/sat_solver.h"
 
+namespace {
 struct lex_error {};
 
 class stream_buffer {
@@ -138,6 +139,8 @@ bool parse_dimacs_core(Buffer & in, std::ostream& err, sat::solver & solver) {
     return true;
 }
 
+}
+
 bool parse_dimacs(std::istream & in, std::ostream& err, sat::solver & solver) {
     stream_buffer _in(in);
     return parse_dimacs_core(_in, err, solver);
diff --git a/src/sat/sat_iff3_finder.cpp b/src/sat/sat_iff3_finder.cpp
deleted file mode 100644
index 32bf70414..000000000
--- a/src/sat/sat_iff3_finder.cpp
+++ /dev/null
@@ -1,214 +0,0 @@
-/*++
-Copyright (c) 2011 Microsoft Corporation
-
-Module Name:
-
-    sat_iff3_finder.cpp
-
-Abstract:
-
-    Find constraints of the form   x = l1 = l2
-    That is, search for clauses of the form
-      ~x \/ l1  \/ ~l2
-      ~x \/ ~l1 \/ l2
-       x \/ l1  \/ l2
-       x \/ ~l1 \/ ~l2
-       
-    The basic idea is to sort the watch lists.
-    
-    This information can be used to propagate equivalences
-    during probing (and search).
-
-    The initial experiments were disappointing.
-    Not using it on the solver.
-
-Author:
-
-    Leonardo de Moura (leonardo) 2011-06-04.
-
-Revision History:
-
---*/
-#include "sat/sat_iff3_finder.h"
-#include "sat/sat_solver.h"
-
-namespace sat {
-
-    struct iff3_lt {
-        bool operator()(watched const & w1, watched const & w2) const {
-            // keep th binary clauses in the beginning
-            if (w2.is_binary_clause()) return false;
-            if (w1.is_binary_clause()) return true;
-            //
-            if (w2.is_ternary_clause()) {
-                if (w1.is_ternary_clause()) {
-                    literal l1_1 = w1.get_literal1();
-                    literal l1_2 = w1.get_literal2();
-                    literal l2_1 = w2.get_literal1();
-                    literal l2_2 = w2.get_literal2();
-                    if (l1_1.index() < l2_1.index()) return true;
-                    if (l1_1.index() > l2_1.index()) return false;
-                    return l1_2.index() < l2_2.index();
-                }
-                return false;
-            }
-            if (w1.is_ternary_clause()) return true;
-            return false;
-        }
-    };
-
-    static void unmark(svector<bool> & marks, literal_vector & to_unmark) {
-        literal_vector::const_iterator it  = to_unmark.begin();
-        literal_vector::const_iterator end = to_unmark.end();
-        for (; it != end; ++it) {
-            marks[it->index()] = false;
-        }
-        to_unmark.reset();
-    }
-
-#define SMALL_WLIST 16
-
-    /**
-       \brief Return true if wlist contains (l1, l2)
-       It assumes wlist have been sorted using iff3_lt
-    */
-    static bool contains(watch_list const & wlist, literal l1, literal l2) {
-        watched k(l1, l2);
-        if (wlist.size() < SMALL_WLIST)
-            return wlist.contains(k);
-        iff3_lt lt;
-        int low  = 0;
-        int high = wlist.size(); 
-        while (true) {
-            int mid = low + ((high - low) / 2);
-            watched const & m = wlist[mid];
-            if (m == k)
-                return true;
-            if (lt(m, k)) {
-                low = mid + 1;
-            }
-            else {
-                SASSERT(lt(k, m));
-                high = mid - 1;
-            }
-            if (low > high)
-                return false;
-        }
-    }
-
-    iff3_finder::iff3_finder(solver & _s):
-        s(_s) {
-    }
-
-    void iff3_finder::sort_watches() {
-        vector<watch_list>::iterator it  = s.m_watches.begin();
-        vector<watch_list>::iterator end = s.m_watches.end();
-        for (; it != end; ++it) {
-            watch_list & wlist = *it;
-            std::stable_sort(wlist.begin(), wlist.end(), iff3_lt());
-        }
-    }
-
-    void iff3_finder::mk_eq(literal l1, literal l2) {
-        s.mk_clause(l1, ~l2);
-        s.mk_clause(~l1, l2);
-    }
-
-    void iff3_finder::operator()() {
-        TRACE("iff3_finder", tout << "starting iff3_finder\n";);
-        sort_watches();
-        
-        unsigned counter = 0;
-
-        svector<bool>   found;
-        found.resize(s.num_vars()*2, false);
-        literal_vector to_unmark;
-
-        typedef std::pair<literal, literal> lit_pair;
-        svector<lit_pair> pairs;
-
-        for (bool_var x = 0; x < s.num_vars(); x++) {
-            literal pos_x(x, false);
-            literal neg_x(x, true);
-            watch_list & pos_wlist = s.get_wlist(neg_x);
-            watch_list & neg_wlist = s.get_wlist(pos_x);
-            // 
-            TRACE("iff3_finder", 
-                  tout << "visiting: " << x << "\n";
-                  tout << "pos:\n";
-                  s.display_watch_list(tout,  pos_wlist);
-                  tout << "\nneg:\n";
-                  s.display_watch_list(tout, neg_wlist);
-                  tout << "\n--------------\n";);
-            // traverse the ternary clauses x \/ l1 \/ l2
-            bool_var curr_v1 = null_bool_var;
-            watch_list::iterator it  = pos_wlist.begin();
-            watch_list::iterator end = pos_wlist.end();
-            for (; it != end; ++it) {
-                if (it->is_binary_clause())
-                    continue;
-                if (it->is_ternary_clause()) {
-                    literal l1  = it->get_literal1();
-                    if (l1.index() < pos_x.index())
-                        break; // stop
-                    literal l2  = it->get_literal2();
-                    bool_var v1 = l1.var();
-                    if (v1 != curr_v1) {
-                        curr_v1 = v1;
-                        unmark(found, to_unmark);
-                        pairs.reset();
-                    }
-                    if (!l1.sign()) {
-                        if (!found[l2.index()]) {
-                            found[l2.index()] = true;
-                            to_unmark.push_back(l2);
-                        }
-                    }
-                    else {
-                        l2.neg();
-                        if (found[l2.index()]) {
-                            // Found clauses x \/ v1 \/ l2 and x \/ ~v1 \/ ~l2
-                            // So, I have to find the clauses
-                            // ~x \/  v1 \/ ~l2
-                            // ~x \/ ~v1 \/ l2
-                            if (contains(neg_wlist, literal(v1, false), ~l2) &&
-                                contains(neg_wlist, literal(v1, true),  l2)) {
-                                // found new iff3
-                                // x = v1 = l2
-                                counter++;
-                                // verbose_stream() << counter << ": " << x << " = " << v1 << " = " << l2 << "\n";
-                                TRACE("iff3_finder", tout << counter << ": " << x << " = " << v1 << " = " << l2 << "\n";);
-                                l1.neg();
-                                svector<lit_pair>::iterator it2  = pairs.begin();
-                                svector<lit_pair>::iterator end2 = pairs.end();
-                                for (; it2 != end2; ++it2) {
-                                    if (it2->first == l1) {
-                                        // l2 == it2->second
-                                        mk_eq(l2, it2->second);
-                                    }
-                                    else if (it2->second == l1) {
-                                        // l2 == it2->first
-                                        mk_eq(l2, it2->first);
-                                    }
-                                    else if (it2->first == l2) {
-                                        // l1 == it2->second
-                                        mk_eq(l1, it2->second);
-                                    }
-                                    else if (it2->second == l2) {
-                                        // l1 == it2->first
-                                        mk_eq(l1, it2->first);
-                                    }
-                                }
-                                pairs.push_back(lit_pair(l1, l2));
-                            }
-                        }
-                    }
-                }
-                else {
-                    break; // stop, no more ternary clauses from this point
-                }
-            }
-        }
-    }
-    
-};
diff --git a/src/sat/sat_iff3_finder.h b/src/sat/sat_iff3_finder.h
deleted file mode 100644
index 27cd6de05..000000000
--- a/src/sat/sat_iff3_finder.h
+++ /dev/null
@@ -1,48 +0,0 @@
-/*++
-Copyright (c) 2011 Microsoft Corporation
-
-Module Name:
-
-    sat_iff3_finder.h
-
-Abstract:
-
-    Find constraints of the form   x = l1 = l2
-    That is, search for clauses of the form
-      ~x \/ l1  \/ ~l2
-      ~x \/ ~l1 \/ l2
-       x \/ l1  \/ l2
-       x \/ ~l1 \/ ~l2
-       
-    The basic idea is to sort the watch lists.
-    
-    This information can be used to propagate equivalences
-    during probing (and search).
-
-Author:
-
-    Leonardo de Moura (leonardo) 2011-06-04.
-
-Revision History:
-
---*/
-#ifndef SAT_IFF3_FINDER_H_
-#define SAT_IFF3_FINDER_H_
-
-#include "sat/sat_types.h"
-
-namespace sat {
-    
-    class iff3_finder {
-        solver & s;
-        void sort_watches();
-        void mk_eq(literal l1, literal l2);
-    public:
-        iff3_finder(solver & s);
-        
-        void operator()();
-    };
-
-};
-
-#endif
diff --git a/src/sat/sat_solver.cpp b/src/sat/sat_solver.cpp
index c3759739f..1b82969be 100644
--- a/src/sat/sat_solver.cpp
+++ b/src/sat/sat_solver.cpp
@@ -1676,12 +1676,6 @@ namespace sat {
     }    
 
 
-    struct clause_size_lt {
-        bool operator()(clause const * c1, clause const * c2) const {
-            return c1->size() < c2->size();
-        }
-    };
-
     void solver::init_assumptions(unsigned num_lits, literal const* lits) {
         if (num_lits == 0 && m_user_scope_literals.empty()) {
             return;
diff --git a/src/sat/sat_solver.h b/src/sat/sat_solver.h
index 593067e08..8aff22f2d 100644
--- a/src/sat/sat_solver.h
+++ b/src/sat/sat_solver.h
@@ -32,7 +32,6 @@ Revision History:
 #include "sat/sat_scc.h"
 #include "sat/sat_asymm_branch.h"
 #include "sat/sat_aig_simplifier.h"
-#include "sat/sat_iff3_finder.h"
 #include "sat/sat_probing.h"
 #include "sat/sat_mus.h"
 #include "sat/sat_binspr.h"
@@ -202,7 +201,6 @@ namespace sat {
         friend class drat;
         friend class elim_eqs;
         friend class bcd;
-        friend class iff3_finder;
         friend class mus;
         friend class probing;
         friend class simplifier;
diff --git a/src/smt/mam.cpp b/src/smt/mam.cpp
index de4473c5b..a501e89f7 100644
--- a/src/smt/mam.cpp
+++ b/src/smt/mam.cpp
@@ -27,6 +27,8 @@ Revision History:
 #include "smt/mam.h"
 #include "smt/smt_context.h"
 
+using namespace smt;
+
 // #define _PROFILE_MAM
 
 // -----------------------------------------
@@ -53,7 +55,7 @@ Revision History:
 
 #define IS_CGR_SUPPORT true
 
-namespace smt {
+namespace {
     // ------------------------------------
     //
     // Trail
@@ -1985,11 +1987,13 @@ namespace smt {
 
         enode * init_continue(cont const * c, unsigned expected_num_args);
 
+#ifdef _TRACE
         void display_reg(std::ostream & out, unsigned reg);
 
         void display_instr_input_reg(std::ostream & out, instruction const * instr);
 
         void display_pc_info(std::ostream & out);
+#endif
 
 #define INIT_ARGS_SIZE 16
 
@@ -2222,6 +2226,7 @@ namespace smt {
         return *(bp.m_it);
     }
 
+#ifdef _TRACE
     void interpreter::display_reg(std::ostream & out, unsigned reg) {
         out << "reg[" << reg << "]: ";
         enode * n = m_registers[reg];
@@ -2273,6 +2278,7 @@ namespace smt {
         out << "\n";
         display_instr_input_reg(out, m_pc);
     }
+#endif
 
     bool interpreter::execute_core(code_tree * t, enode * n) {
         TRACE("trigger_bug", tout << "interpreter::execute_core\n"; t->display(tout); tout << "\nenode\n" << mk_ismt2_pp(n->get_owner(), m) << "\n";);
@@ -2839,6 +2845,7 @@ namespace smt {
         return false;
     } // end of execute_core
 
+#if 0
     void display_trees(std::ostream & out, const ptr_vector<code_tree> & trees) {
         unsigned lbl = 0;
         for (code_tree * tree : trees) {
@@ -2849,6 +2856,7 @@ namespace smt {
             ++lbl;
         }
     }
+#endif
 
     // ------------------------------------
     //
@@ -4010,11 +4018,13 @@ namespace smt {
             SASSERT(approx_subset(r1->get_lbls(), r2->get_lbls()));
         }
     };
+}
 
+namespace smt {
     mam * mk_mam(context & ctx) {
         return alloc(mam_impl, ctx, true);
     }
-};
+}
 
 #ifdef Z3DEBUG
 void pp(smt::code_tree * c) {
diff --git a/src/smt/smt_case_split_queue.cpp b/src/smt/smt_case_split_queue.cpp
index 2c64772e0..87bc2b7c5 100644
--- a/src/smt/smt_case_split_queue.cpp
+++ b/src/smt/smt_case_split_queue.cpp
@@ -25,7 +25,9 @@ Revision History:
 #include "util/map.h"
 #include "util/hashtable.h"
 
-namespace smt {
+using namespace smt;
+
+namespace {
 
     typedef map<bool_var, double, int_hash, default_eq<bool_var> > theory_var_priority_map;
 
@@ -1250,8 +1252,9 @@ namespace smt {
 
         ~theory_aware_branching_queue() override {};
     };
+}
 
-
+namespace smt {
     case_split_queue * mk_case_split_queue(context & ctx, smt_params & p) {
         if (ctx.relevancy_lvl() < 2 && (p.m_case_split_strategy == CS_RELEVANCY || p.m_case_split_strategy == CS_RELEVANCY_ACTIVITY || 
                 p.m_case_split_strategy == CS_RELEVANCY_GOAL)) {
@@ -1281,5 +1284,4 @@ namespace smt {
         }
     }
 
-};
-
+}
diff --git a/src/smt/smt_implied_equalities.cpp b/src/smt/smt_implied_equalities.cpp
index 9119119d3..300280718 100644
--- a/src/smt/smt_implied_equalities.cpp
+++ b/src/smt/smt_implied_equalities.cpp
@@ -30,7 +30,7 @@ Revision History:
 #include "model/model.h"
 #include "solver/solver.h"
 
-namespace smt {
+namespace {
 
     class get_implied_equalities_impl {
         
@@ -177,7 +177,7 @@ namespace smt {
 
             uint_set non_values;
             
-            if (!is_value_sort(m, srt)) {
+            if (!smt::is_value_sort(m, srt)) {
                 for (unsigned i = 0; i < terms.size(); ++i) {
                     non_values.insert(i);
                 }
@@ -370,12 +370,14 @@ namespace smt {
 
     stopwatch get_implied_equalities_impl::s_timer;
     stopwatch get_implied_equalities_impl::s_stats_val_eq_timer;
+}
 
+namespace smt {
     lbool implied_equalities(ast_manager& m, solver& solver, unsigned num_terms, expr* const* terms, unsigned* class_ids) {        
         get_implied_equalities_impl gi(m, solver);
         return gi(num_terms, terms, class_ids);
     }
-};
+}
 
 
 
diff --git a/src/smt/smt_solver.cpp b/src/smt/smt_solver.cpp
index e7ce999df..42f989a8a 100644
--- a/src/smt/smt_solver.cpp
+++ b/src/smt/smt_solver.cpp
@@ -27,7 +27,7 @@ Notes:
 #include "ast/func_decl_dependencies.h"
 #include "util/dec_ref_util.h"
 
-namespace smt {
+namespace {
 
     class smt_solver : public solver_na2as {
 
@@ -445,18 +445,20 @@ namespace smt {
             }
         }
     };
-};
-
-solver * mk_smt_solver(ast_manager & m, params_ref const & p, symbol const & logic) {
-    return alloc(smt::smt_solver, m, p, logic);
 }
 
+solver * mk_smt_solver(ast_manager & m, params_ref const & p, symbol const & logic) {
+    return alloc(smt_solver, m, p, logic);
+}
+
+namespace {
 class smt_solver_factory : public solver_factory {
 public:
     solver * operator()(ast_manager & m, params_ref const & p, bool proofs_enabled, bool models_enabled, bool unsat_core_enabled, symbol const & logic) override {
         return mk_smt_solver(m, p, logic);
     }
 };
+}
 
 solver_factory * mk_smt_solver_factory() {
     return alloc(smt_solver_factory);
diff --git a/src/smt/uses_theory.cpp b/src/smt/uses_theory.cpp
index 64565dc78..10e249aab 100644
--- a/src/smt/uses_theory.cpp
+++ b/src/smt/uses_theory.cpp
@@ -25,7 +25,7 @@ bool uses_theory(expr * n, family_id fid) {
     return uses_theory(n, fid, visited);
 }
 
-namespace uses_theory_ns {
+namespace {
     struct found {}; 
     struct proc {
         family_id m_fid;
@@ -34,16 +34,15 @@ namespace uses_theory_ns {
         void operator()(app * n) { if (n->get_family_id() == m_fid) throw found(); }
         void operator()(quantifier * n) {}
     };
-};
+}
 
 bool uses_theory(expr * n, family_id fid, expr_mark & visited) {
-    uses_theory_ns::proc p(fid);
+    proc p(fid);
     try {
         for_each_expr(p, visited, n);
     }
-    catch (const uses_theory_ns::found &) {
+    catch (const found &) {
         return true;
     }
     return false;
 }
-
diff --git a/src/tactic/arith/probe_arith.cpp b/src/tactic/arith/probe_arith.cpp
index 2561a6d32..1459af244 100644
--- a/src/tactic/arith/probe_arith.cpp
+++ b/src/tactic/arith/probe_arith.cpp
@@ -22,6 +22,8 @@ Revision History:
 #include "ast/arith_decl_plugin.h"
 #include "tactic/goal_util.h"
 
+namespace {
+
 class arith_degree_probe : public probe {
     struct proc {
         ast_manager &            m;
@@ -163,6 +165,8 @@ struct has_nlmul {
     }
 };
 
+}
+
 probe * mk_arith_avg_degree_probe() {
     return alloc(arith_degree_probe, true);
 }
@@ -179,6 +183,7 @@ probe * mk_arith_max_bw_probe() {
     return alloc(arith_bw_probe, false);
 }
 
+namespace {
 struct is_non_qflira_functor {
     struct found {};
     ast_manager & m;
@@ -392,6 +397,8 @@ public:
     }
 };
 
+}
+
 probe * mk_is_qflia_probe() {
     return alloc(is_qflia_probe);
 }
@@ -417,6 +424,8 @@ probe * mk_is_mip_probe() {
 }
 
 
+namespace {
+
 struct is_non_nira_functor {
     struct found {};
     ast_manager & m;
@@ -697,6 +706,8 @@ public:
     }
 };
 
+}
+
 probe * mk_is_qfnia_probe() {
     return alloc(is_qfnia_probe);
 }