recommended by clang-tidy

Device/IO/ReadWriteTiff.cpp

@@ -109,7 +109,7 @@ Datafield* Util::RW::readTiff(std::istream& input_stream)
     if (buf_size != expected_size)
         throw std::runtime_error("Cannot read TIFF file: wrong scanline size" + ref_to_doc);
 
-    tdata_t buf = _TIFFmalloc(buf_size);
+    tdata_t const buf = _TIFFmalloc(buf_size); // tdata_t is void*
     if (!buf)
         throw std::runtime_error("Cannot read TIFF file: failed allocating buffer" + ref_to_doc);
 
@@ -221,7 +221,7 @@ void Util::RW::writeTiff(const Datafield& data, std::ostream& output_stream)
     for (unsigned row = 0; row < (uint32_t)m_height; row++) {
         for (unsigned col = 0; col < line_buf.size(); ++col)
             line_buf[col] = static_cast<sample_t>(data[(m_height - 1 - row) * m_width + col]);
-        memcpy(buf, &line_buf[0], buf_size);
+        memcpy(buf, line_buf.data(), buf_size);
 
         if (TIFFWriteScanline(tiffstream, buf, row) < 0)
             throw std::runtime_error("Cannot write TIFF file: error in TIFFWriteScanline");

GUI/Model/Model/DatafilesTree.cpp

@@ -174,7 +174,7 @@ QVariant DatafilesTree::data(const QModelIndex& index, int role) const
     auto* const item = itemForIndex(index);
 
     if (role == Qt::ToolTipRole)
-        return QString();
+        return {};
 
     if (role == Qt::DisplayRole)
         return item->realItemName();

GUI/View/MaterialEditor/MaterialEditorDialog.cpp

@@ -272,7 +272,7 @@ QString MaterialEditorDialog::chooseMaterial(QWidget* parent, SampleItem* sample
         if (MaterialItem* material = dialog.currentMaterialItem())
             return material->identifier();
 
-    return QString();
+    return {};
 }
 
 void MaterialEditorDialog::addRefractiveMaterial()