Avoid unnecessary copy construction [performance-unnecessary-copy-ini…

…tialization]

src/advanced_inv_pane.cpp

@@ -60,7 +60,7 @@ void advanced_inventory_pane::load_settings( int saved_area_idx,
                              !is_re_enter ) ? saved_area_idx :
                            save_state->area_idx;
     const aim_location location = static_cast<aim_location>( i_location );
-    const advanced_inv_area square = squares[location];
+    const advanced_inv_area &square = squares[location];
     // determine the square's vehicle/map item presence
     bool has_veh_items = square.can_store_in_vehicle() ?
                          !square.veh->get_items( square.vstor ).empty() : false;

src/construction.cpp

@@ -1492,7 +1492,7 @@ void construct::done_appliance( const tripoint_bub_ms &p, Character & )
         return;
     }
 
-    const item base = components.front();
+    const item &base = components.front();
     const vpart_id &vpart = vpart_appliance_from_item( base.typeId() );
 
     // TODO: fix point types

src/consumption.cpp

@@ -320,7 +320,7 @@ std::pair<nutrients, nutrients> Character::compute_nutrient_range(
         our_extra_flags.insert( flag_COOKED );
     }
 
-    const requirement_data requirements = rec.simple_requirements();
+    const requirement_data &requirements = rec.simple_requirements();
     const requirement_data::alter_item_comp_vector &component_requirements =
         requirements.get_components();
 

src/output.cpp

@@ -295,7 +295,7 @@ std::string trim_by_length( const std::string &text, int width )
 
         const std::vector<std::string> color_segments = split_by_color( text );
         for( size_t i = 0; i < color_segments.size() ; ++i ) {
-            std::string seg = color_segments[i];
+            const std::string &seg = color_segments[i];
             if( seg.empty() ) {
                 // TODO: Check is required right now because, for a fully-color-tagged string, split_by_color
                 // returns an empty string first

src/sdltiles.cpp

@@ -768,7 +768,7 @@ std::string cata_tiles::get_omt_id_rotation_and_subtile(
     oter_id ot_id = oter_at( omp );
     const oter_t &ot = *ot_id;
     oter_type_id ot_type_id = ot.get_type_id();
-    oter_type_t ot_type = *ot_type_id;
+    const oter_type_t &ot_type = *ot_type_id;
 
     if( ot_type.has_connections() ) {
         // This would be for connected terrain