Added check for items overflow: there is a path to destination.

src/map.cpp

@@ -4327,12 +4327,19 @@ item &map::add_item_or_charges( const tripoint &pos, item obj, bool overflow )
 
     } else if( overflow ) {
         // ...otherwise try to overflow to adjacent tiles (if permitted)
-        auto tiles = closest_tripoints_first( 2, pos );
+        const int max_dist = 2;
+        auto tiles = closest_tripoints_first( max_dist, pos );
         tiles.erase( tiles.begin() ); // we already tried this position
-        for( const auto &e : tiles ) {
+        const int max_path_length = 4 * max_dist;
+        const pathfinding_settings setting( 0, max_dist, max_path_length, 0, false, true, false, false );
+        for( const tripoint &e : tiles ) {
             if( !inbounds( e ) ) {
                 continue;
             }
+            //must be a path to the target tile
+            if( g->m.route( pos, e, setting ).empty() ) {
+                continue;
+            }
             if( obj.made_of( LIQUID ) || !obj.has_flag( "DROP_ACTION_ONLY_IF_LIQUID" ) ) {
                 if( obj.on_drop( e, *this ) ) {
                     return null_item_reference();