From b76ed6a47fc00d184fbceb518eeb5b18ea8ae93d Mon Sep 17 00:00:00 2001
From: Nikolaj Bjorner <nbjorner@microsoft.com>
Date: Sun, 4 Dec 2022 10:19:39 -0800
Subject: [PATCH] proper fix to #6476

---
 src/ast/simplifiers/demodulator_simplifier.cpp | 6 +++---
 src/ast/substitution/demodulator_rewriter.cpp  | 7 ++-----
 src/ast/substitution/demodulator_rewriter.h    | 3 ---
 3 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/src/ast/simplifiers/demodulator_simplifier.cpp b/src/ast/simplifiers/demodulator_simplifier.cpp
index eb3585606..d7650717e 100644
--- a/src/ast/simplifiers/demodulator_simplifier.cpp
+++ b/src/ast/simplifiers/demodulator_simplifier.cpp
@@ -104,7 +104,7 @@ bool demodulator_simplifier::rewrite1(func_decl* f, expr_ref_vector const& args,
     if (!m_index.find_fwd(f, set))
         return false;
 
-    TRACE("demodulator", tout << "trying to rewrite: " << f->get_name() << " args:\n" << m_new_args << "\n";);
+    TRACE("demodulator", tout << "trying to rewrite: " << f->get_name() << " args:\n" << args << "\n";);
 
     for (unsigned i : *set) {
 
@@ -115,7 +115,7 @@ bool demodulator_simplifier::rewrite1(func_decl* f, expr_ref_vector const& args,
 
         SASSERT(lhs->get_decl() == f);
 
-        TRACE("demodulator", tout << "Matching with demodulator: " << mk_pp(d, m) << std::endl; );
+        TRACE("demodulator", tout << "Matching with demodulator: " << mk_pp(lhs, m) << std::endl; );
 
         if (m_match_subst(lhs, rhs, args.data(), np)) {
             TRACE("demodulator_bug", tout << "succeeded...\n" << mk_pp(rhs, m) << "\n===>\n" << np << "\n";);
@@ -154,7 +154,7 @@ void demodulator_simplifier::reschedule_demodulators(func_decl* f, expr* lhs) {
             continue;        
         if (!m_match_subst.can_rewrite(fml(i), lhs))
             continue;
-        func_decl* f = p.first->get_decl();
+        SASSERT(f == p.first->get_decl());
         m_index.remove_fwd(f, i);
         m_index.remove_bwd(fml(i), i);
         m_todo.push_back(i);
diff --git a/src/ast/substitution/demodulator_rewriter.cpp b/src/ast/substitution/demodulator_rewriter.cpp
index 0b37308c9..7b06234dc 100644
--- a/src/ast/substitution/demodulator_rewriter.cpp
+++ b/src/ast/substitution/demodulator_rewriter.cpp
@@ -847,12 +847,9 @@ struct match_args_aux_proc {
                 SASSERT(r.get_offset() == 1);
                 throw no_match();
             }
-            else {
-                m_subst.insert(n, 0, expr_offset(n, 1));
-            }
         }
-        else
-            throw no_match();
+        else 
+            m_subst.insert(n, 0, expr_offset(n, 1));        
     }
     void operator()(quantifier * n) { throw no_match(); }
     void operator()(app * n) {}
diff --git a/src/ast/substitution/demodulator_rewriter.h b/src/ast/substitution/demodulator_rewriter.h
index 18befc198..3a1e442d5 100644
--- a/src/ast/substitution/demodulator_rewriter.h
+++ b/src/ast/substitution/demodulator_rewriter.h
@@ -111,8 +111,6 @@ class demodulator_match_subst {
     typedef std::pair<expr *, expr *>      expr_pair;
     typedef obj_pair_hashtable<expr, expr> cache;
     
-    void reset();
-    
     ast_manager &         m;
     substitution          m_subst;
     cache                 m_cache;
@@ -229,7 +227,6 @@ class demodulator_rewriter final {
     void remove_bwd_idx(expr* q);
     bool check_fwd_idx_consistency();
     void show_fwd_idx(std::ostream & out);
-    bool can_rewrite(expr * n, expr * lhs);
     
     expr * rewrite(expr * n);
     bool rewrite1(func_decl * f, expr_ref_vector const & args, expr_ref & np);