foo.cc: In member function ‘void trie::build()’:
foo.cc:36:25: warning: this ‘if’ clause does not guard... [-Wmisleading-indentation]
   36 |                         if(trail==1)break;trail=fail[trail];
      |                         ^~
foo.cc:36:43: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the ‘if’
   36 |                         if(trail==1)break;trail=fail[trail];
      |                                           ^~~~~