diff --git a/src/edt/edt/edtInstPropertiesPage.cc b/src/edt/edt/edtInstPropertiesPage.cc
index a76a0dd98..6bf78393d 100644
--- a/src/edt/edt/edtInstPropertiesPage.cc
+++ b/src/edt/edt/edtInstPropertiesPage.cc
@@ -159,7 +159,7 @@ InstPropertiesPage::display_mode_changed (bool)
 void 
 InstPropertiesPage::back ()
 {
-  m_index = m_selection_ptrs.size ();
+  m_index = (unsigned int) m_selection_ptrs.size ();
 }
 
 void 
diff --git a/src/edt/edt/edtMainService.cc b/src/edt/edt/edtMainService.cc
index 0d98f3872..ce4f05a41 100644
--- a/src/edt/edt/edtMainService.cc
+++ b/src/edt/edt/edtMainService.cc
@@ -190,7 +190,7 @@ public:
 
   unsigned int size () const
   {
-    return m_common_inst.size ();
+    return (unsigned int) m_common_inst.size ();
   }
 
   unsigned int cv_index () const
diff --git a/src/edt/edt/edtPropertiesPages.cc b/src/edt/edt/edtPropertiesPages.cc
index c2e5610f3..2c9b7dc9e 100644
--- a/src/edt/edt/edtPropertiesPages.cc
+++ b/src/edt/edt/edtPropertiesPages.cc
@@ -73,7 +73,7 @@ ShapePropertiesPage::setup ()
 void 
 ShapePropertiesPage::back ()
 {
-  m_index = m_selection_ptrs.size ();
+  m_index = (unsigned int) m_selection_ptrs.size ();
 }
 
 void 
diff --git a/src/edt/unit_tests/edtBasicTests.cc b/src/edt/unit_tests/edtBasicTests.cc
index 0edc4e665..5e9eff146 100644
--- a/src/edt/unit_tests/edtBasicTests.cc
+++ b/src/edt/unit_tests/edtBasicTests.cc
@@ -25,6 +25,8 @@
 
 TEST(1) 
 {
+  EXPECT_EQ (1, 1);  //  avoids a compiler warning because of unreferenced _this
+
   //  TODO: add tests for edt specific things
   throw tl::CancelException ();  //  skip this test to indicate that there is nothing yet
 }
diff --git a/src/laybasic/laybasic/layCellTreeModel.cc b/src/laybasic/laybasic/layCellTreeModel.cc
index 73bccb00a..2ecb560ab 100644
--- a/src/laybasic/laybasic/layCellTreeModel.cc
+++ b/src/laybasic/laybasic/layCellTreeModel.cc
@@ -82,11 +82,11 @@ struct cmp_cell_tree_item_vs_name_f
 // --------------------------------------------------------------------
 //  CellTreeItem implementation
 
-CellTreeItem::CellTreeItem (const db::Layout *layout, CellTreeItem *parent, bool is_pcell, size_t cell_index, bool flat, CellTreeModel::Sorting s)
-  : mp_layout (layout), mp_parent (parent), m_sorting (s), m_is_pcell (is_pcell), m_index (0), m_children (), m_cell_index (cell_index)
+CellTreeItem::CellTreeItem (const db::Layout *layout, CellTreeItem *parent, bool is_pcell, size_t cell_or_pcell_index, bool flat, CellTreeModel::Sorting s)
+  : mp_layout (layout), mp_parent (parent), m_sorting (s), m_is_pcell (is_pcell), m_index (0), m_children (), m_cell_or_pcell_index (cell_or_pcell_index)
 {
   if (! flat && ! is_pcell) {
-    m_child_count = mp_layout->cell (m_cell_index).child_cells ();
+    m_child_count = int (mp_layout->cell (cell_index ()).child_cells ());
   } else {
     m_child_count = 0;
   }
@@ -105,8 +105,8 @@ CellTreeItem::display_text () const
 {
   if (m_is_pcell) {
     return name ();
-  } else if (mp_layout->is_valid_cell_index (m_cell_index)) {
-    return mp_layout->cell (m_cell_index).get_display_name ();
+  } else if (mp_layout->is_valid_cell_index (cell_index ())) {
+    return mp_layout->cell (cell_index ()).get_display_name ();
   } else {
     return std::string ();
   }
@@ -125,7 +125,7 @@ CellTreeItem::child (int index)
 
     //  create a list of child sub-item
 
-    const db::Cell *cell = & mp_layout->cell (m_cell_index);
+    const db::Cell *cell = & mp_layout->cell (cell_index ());
 
     m_children.reserve (m_child_count);
 
@@ -148,7 +148,7 @@ CellTreeItem::child (int index)
 db::cell_index_type
 CellTreeItem::cell_index () const
 {
-  return m_cell_index;
+  return db::cell_index_type (m_cell_or_pcell_index);
 }
 
 CellTreeItem *
@@ -161,9 +161,9 @@ const char *
 CellTreeItem::name () const
 {
   if (! m_is_pcell) {
-    return mp_layout->cell_name (m_cell_index);
+    return mp_layout->cell_name (cell_index ());
   } else {
-    return mp_layout->pcell_header (m_cell_index)->get_name ().c_str ();
+    return mp_layout->pcell_header (m_cell_or_pcell_index)->get_name ().c_str ();
   }
 }
 
@@ -214,7 +214,7 @@ CellTreeItem::by_area_less_than (const CellTreeItem *b) const
     return m_is_pcell > b->is_pcell ();
   }
   // Hint: since mp_layout == b.mp_layout, not conversion to um^2 is required because of different DBU
-  return mp_layout->cell (m_cell_index).bbox ().area () < b->mp_layout->cell (b->m_cell_index).bbox ().area ();
+  return mp_layout->cell (cell_index ()).bbox ().area () < b->mp_layout->cell (b->cell_index ()).bbox ().area ();
 }
 
 bool
@@ -224,7 +224,7 @@ CellTreeItem::by_area_equal_than (const CellTreeItem *b) const
     return false;
   }
   // Hint: since mp_layout == b.mp_layout, not conversion to um^2 is required because of different DBU
-  return mp_layout->cell (m_cell_index).bbox ().area () == b->mp_layout->cell (b->m_cell_index).bbox ().area ();
+  return mp_layout->cell (cell_index ()).bbox ().area () == b->mp_layout->cell (b->cell_index ()).bbox ().area ();
 }
 
 // --------------------------------------------------------------------
diff --git a/src/laybasic/laybasic/layCellTreeModel.h b/src/laybasic/laybasic/layCellTreeModel.h
index 7a892545d..e9c0afa9f 100644
--- a/src/laybasic/laybasic/layCellTreeModel.h
+++ b/src/laybasic/laybasic/layCellTreeModel.h
@@ -241,7 +241,7 @@ private:
 class CellTreeItem
 {
 public:
-  CellTreeItem (const db::Layout *layout, CellTreeItem *parent, bool is_pcell, size_t cell_index, bool flat, CellTreeModel::Sorting sorting);
+  CellTreeItem (const db::Layout *layout, CellTreeItem *parent, bool is_pcell, size_t cell_or_pcell_index, bool flat, CellTreeModel::Sorting sorting);
   ~CellTreeItem ();
 
   int children () const;
@@ -279,7 +279,7 @@ private:
   size_t m_index;
   std::vector<CellTreeItem *> m_children;
   int m_child_count;
-  size_t m_cell_index;
+  size_t m_cell_or_pcell_index;
 
   const char *name () const;
 };
diff --git a/src/laybasic/laybasic/layColorPalette.cc b/src/laybasic/laybasic/layColorPalette.cc
index c6a09b7b7..3330dbe89 100644
--- a/src/laybasic/laybasic/layColorPalette.cc
+++ b/src/laybasic/laybasic/layColorPalette.cc
@@ -124,7 +124,7 @@ ColorPalette::color_by_index (unsigned int n) const
 unsigned int 
 ColorPalette::colors () const
 {
-  return m_colors.size ();
+  return (unsigned int) m_colors.size ();
 }
 
 unsigned int
@@ -136,7 +136,7 @@ ColorPalette::luminous_color_index_by_index (unsigned int n) const
 unsigned int 
 ColorPalette::luminous_colors () const
 {
-  return m_luminous_color_indices.size ();
+  return (unsigned int) m_luminous_color_indices.size ();
 }
 
 void 
diff --git a/src/laybasic/laybasic/layGridNet.cc b/src/laybasic/laybasic/layGridNet.cc
index b7428c6f5..be3b4a7e4 100644
--- a/src/laybasic/laybasic/layGridNet.cc
+++ b/src/laybasic/laybasic/layGridNet.cc
@@ -326,9 +326,9 @@ public:
     int x = p.x (), y = p.y ();
 
     if (halign < 0) {
-      x -= ff.width () * strlen (t);
+      x -= ff.width () * int (strlen (t));
     } else if (halign == 0) {
-      x -= ff.width () * strlen (t) / 2;
+      x -= ff.width () * int (strlen (t)) / 2;
     }
 
     if (valign < 0) {
diff --git a/src/laybasic/laybasic/layLineStylePalette.cc b/src/laybasic/laybasic/layLineStylePalette.cc
index 19ba0fc1e..a73c65780 100644
--- a/src/laybasic/laybasic/layLineStylePalette.cc
+++ b/src/laybasic/laybasic/layLineStylePalette.cc
@@ -89,7 +89,7 @@ LineStylePalette::style_by_index (unsigned int n) const
 unsigned int 
 LineStylePalette::styles () const
 {
-  return m_styles.size ();
+  return (unsigned int) m_styles.size ();
 }
 
 void 
diff --git a/src/lib/unit_tests/libBasicTests.cc b/src/lib/unit_tests/libBasicTests.cc
index 4da3386a7..249c74ccb 100644
--- a/src/lib/unit_tests/libBasicTests.cc
+++ b/src/lib/unit_tests/libBasicTests.cc
@@ -25,6 +25,8 @@
 
 TEST(1) 
 {
+  EXPECT_EQ (1, 1);  //  avoids a compiler warning because of unreferenced _this
+
   //  TODO: add tests for lib specific things
   throw tl::CancelException ();  //  skip this test to indicate that there is nothing yet
 }
diff --git a/src/lym/unit_tests/lymBasicTests.cc b/src/lym/unit_tests/lymBasicTests.cc
index e027ccbd5..b230abb9a 100644
--- a/src/lym/unit_tests/lymBasicTests.cc
+++ b/src/lym/unit_tests/lymBasicTests.cc
@@ -25,6 +25,8 @@
 
 TEST(1) 
 {
+  EXPECT_EQ (1, 1);  //  avoids a compiler warning because of unreferenced _this
+
   //  TODO: add tests for lym specific things
   throw tl::CancelException ();  //  skip this test to indicate that there is nothing yet
 }