From a36254f10422a6e613bae67be9e83e42463c1c4d Mon Sep 17 00:00:00 2001
From: CEisenhofer <clemens.eisenhofer@tuwien.ac.at>
Date: Thu, 9 Apr 2026 13:47:29 +0200
Subject: [PATCH] Some more bug fixes

---
 src/smt/seq/seq_nielsen.cpp    | 15 ++++++++++++++-
 src/smt/seq/seq_nielsen.h      | 13 ++-----------
 src/smt/seq/seq_nielsen_pp.cpp |  2 +-
 src/smt/seq/seq_regex.cpp      |  5 ++---
 src/smt/theory_nseq.cpp        |  6 +++---
 5 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/src/smt/seq/seq_nielsen.cpp b/src/smt/seq/seq_nielsen.cpp
index 518818b0f..ac4b818b4 100644
--- a/src/smt/seq/seq_nielsen.cpp
+++ b/src/smt/seq/seq_nielsen.cpp
@@ -35,6 +35,7 @@ NSB review:
 #include "ast/rewriter/th_rewriter.h"
 #include "ast/rewriter/seq_skolem.h"
 #include "ast/rewriter/var_subst.h"
+#include "smt/smt_enode.h"
 #include "util/statistics.h"
 #include <algorithm>
 #include <cstdlib>
@@ -247,6 +248,18 @@ namespace seq {
         return false;
     }
 
+    void nielsen_node::add_str_eq(str_eq const& eq) {
+        SASSERT(eq.m_lhs != nullptr);
+        SASSERT(eq.m_rhs != nullptr);
+        m_str_eq.push_back(eq);
+    }
+
+    void nielsen_node::add_str_mem(str_mem const& mem) {
+        SASSERT(mem.m_str != nullptr);
+        SASSERT(mem.m_regex != nullptr);
+        m_str_mem.push_back(mem);
+    }
+
     void nielsen_node::add_constraint(constraint const &c) {
         auto& m = graph().get_manager();
         if (m.is_and(c.fml)) {
@@ -1137,7 +1150,7 @@ namespace seq {
             dep_tracker dep = mem.m_dep;
             if (m_graph.check_regex_widening(*this, mem.m_str, mem.m_regex, dep)) {
                 set_general_conflict();
-                set_conflict(backtrack_reason::regex, dep);
+                set_conflict(backtrack_reason::regex_widening, dep);
                 return simplify_result::conflict;
             }
         }
diff --git a/src/smt/seq/seq_nielsen.h b/src/smt/seq/seq_nielsen.h
index 13a68894a..85cda96b2 100644
--- a/src/smt/seq/seq_nielsen.h
+++ b/src/smt/seq/seq_nielsen.h
@@ -560,17 +560,8 @@ namespace seq {
         vector<str_mem> const& str_mems() const { return m_str_mem; }
         vector<str_mem>& str_mems() { return m_str_mem; }
 
-        void add_str_eq(str_eq const& eq) {
-            SASSERT(eq.m_lhs != nullptr);
-            SASSERT(eq.m_rhs != nullptr);
-            m_str_eq.push_back(eq);
-        }
-        void add_str_mem(str_mem const& mem) {
-            SASSERT(mem.m_str != nullptr);
-            SASSERT(mem.m_regex != nullptr);
-            m_str_mem.push_back(mem);
-        }
-
+        void add_str_eq(str_eq const& eq);
+        void add_str_mem(str_mem const& mem);
         void add_constraint(constraint const &ic);
 
         vector<constraint> const& constraints() const { return m_constraints; }
diff --git a/src/smt/seq/seq_nielsen_pp.cpp b/src/smt/seq/seq_nielsen_pp.cpp
index 956f5a33a..c04fd7588 100644
--- a/src/smt/seq/seq_nielsen_pp.cpp
+++ b/src/smt/seq/seq_nielsen_pp.cpp
@@ -287,7 +287,7 @@ namespace seq {
             std::string res;
             if (ap->get_num_args() == 0)
                 return "&#8709;";
-            res = regex_expr_html(ap->get_arg(1), m, seq);
+            res = regex_expr_html(ap->get_arg(0), m, seq);
             for (unsigned i = 1; i < ap->get_num_args(); ++i) {
                 res += " | ";
                 res += regex_expr_html(ap->get_arg(i), m, seq);
diff --git a/src/smt/seq/seq_regex.cpp b/src/smt/seq/seq_regex.cpp
index 8be41ab5f..556c36cb9 100644
--- a/src/smt/seq/seq_regex.cpp
+++ b/src/smt/seq/seq_regex.cpp
@@ -577,7 +577,6 @@ namespace seq {
                 }
             }
         }
-
         return l_true;
     }
 
@@ -667,8 +666,7 @@ namespace seq {
         euf::snode* result = nullptr;
 
         for (auto const& mem : node.str_mems()) {
-            if (!mem.m_str || !mem.m_regex)
-                continue;
+            SASSERT(mem.m_str && mem.m_regex);
             // Primitive constraint: str is a single variable
             if (!mem.is_primitive())
                 continue;
@@ -679,6 +677,7 @@ namespace seq {
 
             if (!result) {
                 result = mem.m_regex;
+                dep = dep_mgr.mk_join(dep, mem.m_dep);
             }
             else {
                 expr* r1 = result->get_expr();
diff --git a/src/smt/theory_nseq.cpp b/src/smt/theory_nseq.cpp
index 5a9e53ecb..c4be3d4d5 100644
--- a/src/smt/theory_nseq.cpp
+++ b/src/smt/theory_nseq.cpp
@@ -239,7 +239,7 @@ namespace smt {
 
     void theory_nseq::assign_eh(bool_var v, bool is_true) {
         expr* e = ctx.bool_var2expr(v);
-        // std::cout << "assigned " << mk_pp(e, m) << " = " << is_true << std::endl;
+        // std::cout << "assigned [" << sat::literal(v, is_true) << "] " << mk_pp(e, m) << " = " << is_true << std::endl;
         expr *s = nullptr, *re = nullptr, *a = nullptr, *b = nullptr;
         TRACE(seq, tout << (is_true ? "" : "¬") << mk_bounded_pp(e, m, 3) << "\n";);
         if (m_seq.str.is_in_re(e, s, re)) {
@@ -687,7 +687,7 @@ namespace smt {
                 v.reset();
             }
         };
-        std::cout << "Nielsen assumptions:\n";
+        //std::cout << "Nielsen assumptions:\n";
         ctx.push_trail(reset_vector(m_nielsen_literals));
         for (auto const& c : m_nielsen.sat_node()->constraints()) {
             bool was_internalized = ctx.e_internalized(c.fml);   
@@ -715,7 +715,7 @@ namespace smt {
                 break;
             }
         }
-        std::cout << std::endl;
+        // std::cout << std::endl;
         if (has_undef)
             return false;
         return true;