build: clear 50 warnings - pessimizing moves and null checks that cannot fail (#15408)

* build: remove std::move that blocks copy elision

std::move wrapped around a temporary, or around a local being returned,
stops the compiler constructing it in place. Each edit is the fix clang
suggests, which is to delete the std::move call and keep its argument.

Three of the 39 sites save a move, the two return std::move(local) in
Print.cpp and TreeSupport.cpp:2749. The rest are equivalent either way
and match how the codebase already writes this elsewhere.

Clears 39 -Wpessimizing-move warnings.

* build: drop null checks on references and this

A reference cannot be bound to null and this cannot be null, so the
compiler folds these conditions to true and drops the guard. Seven are
if (&bitmap && bitmap.IsOk()), where IsOk() already does the work; two
test this directly. The guarded code runs either way, so removing the
dead operand changes nothing.

Clears 11 -Wundefined-bool-conversion warnings.

src/slic3r/GUI/ImageDPIFrame.cpp

@@ -74,7 +74,7 @@ bool ImageDPIFrame::Show(bool show)
 }
 
 void ImageDPIFrame::set_bitmap(const wxBitmap &bit_map) {
-    if (&bit_map && bit_map.IsOk()) {
+    if (bit_map.IsOk()) {
         m_bitmap->SetBitmap(bit_map);
     }
 }

src/slic3r/GUI/Plater.cpp

@@ -3870,7 +3870,7 @@ bool Sidebar::reset_bed_type_combox_choices(bool is_sidebar_init)
         }
     }
     m_last_combo_bedtype_count = p->combo_printer_bed->GetCount();
-    if (!is_sidebar_init && &p->plater->get_partplate_list()) {
+    if (!is_sidebar_init) {
         p->plater->get_partplate_list().check_all_plate_local_bed_type(m_cur_combox_bed_types);
     }
     return true;

src/slic3r/GUI/Printer/PrinterFileSystem.cpp

@@ -662,10 +662,10 @@ PrinterFileSystem::File const &PrinterFileSystem::GetFile(size_t index, bool &se
 void PrinterFileSystem::Attached()
 {
     boost::unique_lock lock(m_mutex);
-    m_recv_thread = std::move(boost::thread([w = weak_from_this()] {
+    m_recv_thread = boost::thread([w = weak_from_this()] {
         boost::shared_ptr<PrinterFileSystem> s = w.lock();
         if (s) s->RecvMessageThread();
-    }));
+    });
 }
 
 void PrinterFileSystem::Start()

src/slic3r/GUI/SelectMachine.cpp

@@ -483,7 +483,7 @@ SelectMachineDialog::SelectMachineDialog(Plater *plater)
 
     m_link_edit_nozzle->Bind(wxEVT_LEFT_DOWN, [this](auto &e) {
 
-        if (this && this->m_is_in_sending_mode) {
+        if (m_is_in_sending_mode) {
             return;
         }
 

src/slic3r/GUI/SendToPrinter.cpp

@@ -978,18 +978,16 @@ void SendToPrinterDialog::on_ok(wxCommandEvent &event)
         m_send_job->on_check_ip_address_fail([this, token = std::weak_ptr(m_token)](int result) {
              CallAfter([token, this] {
                 if (token.expired()) { return; }
-                if (this) {
-                    SendFailedConfirm sfcDlg;
-                    auto res = sfcDlg.ShowModal();
-                    m_status_bar->cancel();
+                SendFailedConfirm sfcDlg;
+                auto res = sfcDlg.ShowModal();
+                m_status_bar->cancel();
 
-                    if (res == wxYES) {
-                        wxQueueEvent(m_button_ensure, new wxCommandEvent(wxEVT_BUTTON));
-                    } else if (res == wxAPPLY) {
-                        wxCommandEvent *evt = new wxCommandEvent(EVT_CLEAR_IPADDRESS);
-                        wxQueueEvent(this, evt);
-                        wxGetApp().show_ip_address_enter_dialog();
-                    }
+                if (res == wxYES) {
+                    wxQueueEvent(m_button_ensure, new wxCommandEvent(wxEVT_BUTTON));
+                } else if (res == wxAPPLY) {
+                    wxCommandEvent *evt = new wxCommandEvent(EVT_CLEAR_IPADDRESS);
+                    wxQueueEvent(this, evt);
+                    wxGetApp().show_ip_address_enter_dialog();
                 }
             });
         });

src/slic3r/GUI/Widgets/AxisCtrlButton.cpp

@@ -124,7 +124,7 @@ void AxisCtrlButton::SetInnerBackgroundColor(StateColor const& color)
 
 void AxisCtrlButton::SetBitmap(ScalableBitmap &bmp)
 {
-    if (&bmp  && (& bmp.bmp()) && (bmp.bmp().IsOk())) {
+    if (bmp.bmp().IsOk()) {
         m_icon = bmp;
     }
 }

src/slic3r/GUI/Widgets/ComboBox.cpp

@@ -208,7 +208,7 @@ bool ComboBox::SetFont(wxFont const& font)
 
 int ComboBox::Append(const wxString &item, const wxBitmap &bitmap, int style)
 {
-    if (&bitmap && bitmap.IsOk()) {
+    if (bitmap.IsOk()) {
         return Append(item, bitmap, nullptr, style);
     }
     return Append(item, wxNullBitmap, nullptr, style);
@@ -219,7 +219,7 @@ int ComboBox::Append(const wxString &text,
                      void *          clientData,
                      int style)
 {
-    if (&bitmap && bitmap.IsOk()) {
+    if (bitmap.IsOk()) {
         return Append(text, bitmap, wxString{}, clientData, style);
     }
     return Append(text, wxNullBitmap, wxString{}, clientData, style);
@@ -237,7 +237,7 @@ int ComboBox::Append(const wxString &text,
                      void *clientData,
                      int style)
 {
-    auto valid_bit_map = (&bitmap && bitmap.IsOk()) ? bitmap : wxNullBitmap;
+    auto valid_bit_map = bitmap.IsOk() ? bitmap : wxNullBitmap;
     Item item{text, wxEmptyString, valid_bit_map, valid_bit_map, clientData, group_key, group_label};
     item.style = style;
     items.push_back(item);
@@ -333,7 +333,7 @@ wxBitmap ComboBox::GetItemBitmap(unsigned int n) { return items[n].icon; }
 void ComboBox::SetItemBitmap(unsigned int n, wxBitmap const &bitmap)
 {
     if (n >= items.size()) return;
-    items[n].icon = (&bitmap && bitmap.IsOk()) ? bitmap : wxNullBitmap;
+    items[n].icon = bitmap.IsOk() ? bitmap : wxNullBitmap;
     drop.Invalidate();
 }