diff --git a/src/api/dotnet/Optimize.cs b/src/api/dotnet/Optimize.cs
index 9a7bd3bd1..66b0df82c 100644
--- a/src/api/dotnet/Optimize.cs
+++ b/src/api/dotnet/Optimize.cs
@@ -53,6 +53,47 @@ namespace Microsoft.Z3
             }
         }
 
+	/// <summary>
+	/// Sets parameter on the optimize solver
+	/// </summary>
+	public void Set(string name, bool value) { Parameters = Context.MkParams().Add(name, value); }
+	/// <summary>
+	/// Sets parameter on the optimize solver
+	/// </summary>
+	public void Set(string name, uint value) { Parameters = Context.MkParams().Add(name, value); }
+	/// <summary>
+	/// Sets parameter on the optimize solver
+	/// </summary>
+	public void Set(string name, double value) { Parameters = Context.MkParams().Add(name, value); }
+	/// <summary>
+	/// Sets parameter on the optimize solver
+	/// </summary>
+	public void Set(string name, string value) { Parameters = Context.MkParams().Add(name, value); }
+	/// <summary>
+	/// Sets parameter on the optimize solver
+	/// </summary>
+	public void Set(string name, Symbol value) { Parameters = Context.MkParams().Add(name, value); }
+	/// <summary>
+	/// Sets parameter on the optimize solver
+	/// </summary>
+	public void Set(Symbol name, bool value) { Parameters = Context.MkParams().Add(name, value); }
+	/// <summary>
+	/// Sets parameter on the optimize solver
+	/// </summary>
+	public void Set(Symbol name, uint value) { Parameters = Context.MkParams().Add(name, value); }
+	/// <summary>
+	/// Sets parameter on the optimize solver
+	/// </summary>
+	public void Set(Symbol name, double value) { Parameters = Context.MkParams().Add(name, value); }
+	/// <summary>
+	/// Sets parameter on the optimize solver
+	/// </summary>
+	public void Set(Symbol name, string value) { Parameters = Context.MkParams().Add(name, value); }
+	/// <summary>
+	/// Sets parameter on the optimize solver
+	/// </summary>
+	public void Set(Symbol name, Symbol value) { Parameters = Context.MkParams().Add(name, value); }
+
         /// <summary>
         /// Retrieves parameter descriptions for Optimize solver.
         /// </summary>
diff --git a/src/ast/array_decl_plugin.cpp b/src/ast/array_decl_plugin.cpp
index a470bd353..f7a299131 100644
--- a/src/ast/array_decl_plugin.cpp
+++ b/src/ast/array_decl_plugin.cpp
@@ -605,7 +605,6 @@ bool array_recognizers::is_const(expr* e, expr*& v) const {
 }
 
 bool array_recognizers::is_store_ext(expr* _e, expr_ref& a, expr_ref_vector& args, expr_ref& value) {
-    ast_manager& m = a.m();
     if (is_store(_e)) {
         app* e = to_app(_e);
         a = e->get_arg(0);
diff --git a/src/sat/sat_solver.cpp b/src/sat/sat_solver.cpp
index a0bd94303..9241c4eaa 100644
--- a/src/sat/sat_solver.cpp
+++ b/src/sat/sat_solver.cpp
@@ -2508,13 +2508,12 @@ namespace sat {
         TRACE("sat_lemma", tout << "new lemma size: " << m_lemma.size() << "\n" << m_lemma << "\n";);
 
         unsigned new_scope_lvl       = 0;
-        bool sub_min = false, res_min = false;
         if (!m_lemma.empty()) {
             if (m_config.m_minimize_lemmas) {
-                res_min = minimize_lemma();
+                minimize_lemma();
                 reset_lemma_var_marks();
                 if (m_config.m_dyn_sub_res)
-                    sub_min = dyn_sub_res();
+                    dyn_sub_res();
                 TRACE("sat_lemma", tout << "new lemma (after minimization) size: " << m_lemma.size() << "\n" << m_lemma << "\n";);
             }
             else
diff --git a/src/tactic/core/special_relations_tactic.cpp b/src/tactic/core/special_relations_tactic.cpp
index a8b74db31..0016e2fe0 100644
--- a/src/tactic/core/special_relations_tactic.cpp
+++ b/src/tactic/core/special_relations_tactic.cpp
@@ -135,7 +135,6 @@ void special_relations_tactic::operator()(goal_ref const & g, goal_ref_buffer &
     func_decl_replace replace(m);
     unsigned_vector to_delete;
     for(auto const& kv : goal_features) {
-        func_decl* sp = nullptr;
         sr_property feature = kv.m_value.m_sp_features;
         switch (feature) {
         case sr_po: