/in/foo.cc: In function 'int main()':
/in/foo.cc:3:22: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
    3 | #define For(i, l, r) for (register int i = (l), i##end = (int)(r); i <= i##end; ++i)
      |                      ^~~
/in/foo.cc:72:5: note: in expansion of macro 'For'
   72 |     For (i, 1, n) G[n + 1][i] = 1.0; G[n + 1][n + 2] = 1.0;
      |     ^~~
/in/foo.cc:72:38: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   72 |     For (i, 1, n) G[n + 1][i] = 1.0; G[n + 1][n + 2] = 1.0;
      |                                      ^