/in/p2.cpp: In function 'opaque_list* insert_list(list_t, list_t, unsigned int)':
/in/p2.cpp:134:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if ( list_first(first) == n ) { return append( second, list_rest(first) ); }
          ~~~~~~~~~~~~~~~~~~^~~~
/in/p2.cpp: In function 'opaque_list* chop(list_t, unsigned int)':
/in/p2.cpp:145:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if ( size(list_rest(list)) == n ) {return list_make(); }
          ~~~~~~~~~~~~~~~~~~~~~~^~~~