View Compilation Error

0_0_38713926_18918.cpp: In function 'long long int SegmentTree::queryMaxLength(long long int, long long int)':
0_0_38713926_18918.cpp:103:38: error: cannot bind non-const lvalue reference of type 'SegmentTree::Node&' to an rvalue of type 'SegmentTree::Node'
  103 |             res1=mergeNodes(queryNode(1,dfn[topx],dfn[x]),res1);
      |                             ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
0_0_38713926_18918.cpp:78:27: note:   initializing argument 1 of 'SegmentTree::Node SegmentTree::mergeNodes(Node&, Node&)'
   78 |     Node mergeNodes(Node &L,Node &R){
      |                     ~~~~~~^
0_0_38713926_18918.cpp:107:34: error: cannot bind non-const lvalue reference of type 'SegmentTree::Node&' to an rvalue of type 'SegmentTree::Node'
  107 |         res2=mergeNodes(queryNode(1,dfn[x],dfn[y]),res2);
      |                         ~~~~~~~~~^~~~~~~~~~~~~~~~~
0_0_38713926_18918.cpp:78:27: note:   initializing argument 1 of 'SegmentTree::Node SegmentTree::mergeNodes(Node&, Node&)'
   78 |     Node mergeNodes(Node &L,Node &R){
      |                     ~~~~~~^