diff --git a/src/db/db/dbBoxScanner.h b/src/db/db/dbBoxScanner.h
index 07b5c8319..8183396e4 100644
--- a/src/db/db/dbBoxScanner.h
+++ b/src/db/db/dbBoxScanner.h
@@ -122,7 +122,7 @@ struct box_scanner_receiver
    *  The finish method is called when an object is no longer in the queue and can be
    *  discarded.
    */
-  virtual void finish (const Obj * /*obj*/, const Prop & /*prop*/) { }
+  virtual void finish (const Obj * /*obj*/, Prop /*prop*/) { }
 
   /**
    *  @brief Callback for an interaction of o1 with o2.
@@ -130,7 +130,7 @@ struct box_scanner_receiver
    *  This method is called when the object o1 interacts with o2 within the current 
    *  definition.
    */
-  virtual void add (const Obj * /*o1*/, const Prop & /*p1*/, const Obj * /*o2*/, const Prop & /*p2*/) { }
+  virtual void add (const Obj * /*o1*/, Prop /*p1*/, const Obj * /*o2*/, Prop /*p2*/) { }
 
   /**
    *  @brief Indicates whether the scanner may stop
@@ -1043,7 +1043,7 @@ public:
   /**
    *  @brief Implementation of the box scanner receiver class
    */
-  void finish (const Obj *obj, const Prop &prop)
+  void finish (const Obj *obj, Prop prop)
   {
     om_iterator_type omi = m_om.find (om_key_type (obj, prop));
     if (omi != m_om.end ()) {
@@ -1089,7 +1089,7 @@ public:
   /**
    *  @brief Implementation of the box scanner receiver class
    */
-  void add (const Obj *o1, const Prop &p1, const Obj *o2, const Prop &p2)
+  void add (const Obj *o1, Prop p1, const Obj *o2, Prop p2)
   {
     om_iterator_type om1 = m_om.find (om_key_type (o1, p1));
     om_iterator_type om2 = m_om.find (om_key_type (o2, p2));
diff --git a/src/db/db/dbRegionUtils.cc b/src/db/db/dbRegionUtils.cc
index ef0b5ac0a..e4e33e563 100644
--- a/src/db/db/dbRegionUtils.cc
+++ b/src/db/db/dbRegionUtils.cc
@@ -108,7 +108,7 @@ static inline bool shields (const db::EdgePair &ep, const db::Edge &q)
 }
 
 void
-Edge2EdgeCheckBase::finish (const Edge *o, const size_t &p)
+Edge2EdgeCheckBase::finish (const Edge *o, size_t p)
 {
   if (m_has_negative_edge_output && m_pass == 1 && m_pseudo_edges.find (std::make_pair (*o, p)) == m_pseudo_edges.end ()) {
 
diff --git a/src/db/db/dbRegionUtils.h b/src/db/db/dbRegionUtils.h
index cd759cb4f..62fca5cd3 100644
--- a/src/db/db/dbRegionUtils.h
+++ b/src/db/db/dbRegionUtils.h
@@ -611,7 +611,7 @@ public:
   /**
    *  @brief Reimplementation of the box_scanner_receiver interface
    */
-  void finish (const Edge *o, const size_t &);
+  void finish (const Edge *o, size_t);
 
   /**
    *  @brief Gets a value indicating whether the check requires different layers
diff --git a/src/lay/lay/layTechSetupDialog.cc b/src/lay/lay/layTechSetupDialog.cc
index 6ab86f668..17c7ef644 100644
--- a/src/lay/lay/layTechSetupDialog.cc
+++ b/src/lay/lay/layTechSetupDialog.cc
@@ -708,7 +708,7 @@ TechSetupDialog::update ()
 }
 
 int
-TechSetupDialog::exec (db::Technologies &technologies)
+TechSetupDialog::exec_dialog (db::Technologies &technologies)
 {
   if (s_first_show) {
     TipDialog td (this,
diff --git a/src/lay/lay/layTechSetupDialog.h b/src/lay/lay/layTechSetupDialog.h
index 03b608e4b..27bf8b3fb 100644
--- a/src/lay/lay/layTechSetupDialog.h
+++ b/src/lay/lay/layTechSetupDialog.h
@@ -149,7 +149,7 @@ public:
   TechSetupDialog (QWidget *parent);
   ~TechSetupDialog ();
 
-  int exec (db::Technologies &technologies);
+  int exec_dialog (db::Technologies &technologies);
 
 protected slots:
   void current_tech_changed (QTreeWidgetItem *current, QTreeWidgetItem *previous);
diff --git a/src/lay/lay/layTechnologyController.cc b/src/lay/lay/layTechnologyController.cc
index 441163065..883869709 100644
--- a/src/lay/lay/layTechnologyController.cc
+++ b/src/lay/lay/layTechnologyController.cc
@@ -436,7 +436,7 @@ TechnologyController::show_editor ()
 {
   db::Technologies new_tech = *db::Technologies ().instance ();
 
-  if (mp_editor && mp_editor->exec (new_tech)) {
+  if (mp_editor && mp_editor->exec_dialog (new_tech)) {
 
     std::string err_msg;
 
diff --git a/src/laybasic/laybasic/layLibrariesView.cc b/src/laybasic/laybasic/layLibrariesView.cc
index 55cff7d47..e80568f15 100644
--- a/src/laybasic/laybasic/layLibrariesView.cc
+++ b/src/laybasic/laybasic/layLibrariesView.cc
@@ -669,7 +669,7 @@ LibrariesView::do_update_content (int lib_index)
     mp_cell_lists.pop_back ();
   }
 
-  for (size_t i = imin; i < m_libraries.size () && i < mp_selector->count () && i <= imax; ++i) {
+  for (size_t i = imin; i < m_libraries.size () && i < size_t (mp_selector->count ()) && i <= imax; ++i) {
     mp_selector->setItemText (int (i), tl::to_qstring (display_string (int (i))));
   }
   while (mp_selector->count () < int (m_libraries.size ())) {
diff --git a/src/plugins/streamers/dxf/db_plugin/dbDXFReader.cc b/src/plugins/streamers/dxf/db_plugin/dbDXFReader.cc
index 8b0d598af..56b5113c2 100644
--- a/src/plugins/streamers/dxf/db_plugin/dbDXFReader.cc
+++ b/src/plugins/streamers/dxf/db_plugin/dbDXFReader.cc
@@ -3037,7 +3037,7 @@ DXFReader::read_int64 ()
     if (! ex.try_read (x) || ! ex.at_end ()) {
       error ("Expected an ASCII numerical value");
     }
-    if (x < std::numeric_limits<long long>::min() || x > std::numeric_limits<long long>::max()) {
+    if (x < double (std::numeric_limits<long long>::min()) || x > double (std::numeric_limits<long long>::max())) {
       error ("Value is out of limits for a 64 bit signed integer");
     }
     return (long long) x;
diff --git a/src/plugins/tools/net_tracer/lay_plugin/layNetTracerDialog.cc b/src/plugins/tools/net_tracer/lay_plugin/layNetTracerDialog.cc
index 7b8b24dc8..3c7da9d8b 100644
--- a/src/plugins/tools/net_tracer/lay_plugin/layNetTracerDialog.cc
+++ b/src/plugins/tools/net_tracer/lay_plugin/layNetTracerDialog.cc
@@ -1428,7 +1428,7 @@ NetTracerDialog::get_trace_depth()
     QString depth = depth_le->text ().trimmed ();
     if (! depth.isEmpty ()) {
       tl::from_string (tl::to_string (depth), n);
-      if (n < 0 || n > std::numeric_limits<size_t>::max ()) {
+      if (n < 0 || n > double (std::numeric_limits<size_t>::max ())) {
         n = 0.0;
       }
     }