File "bigarray_index_labels.ml", line 13, characters 0-12:
13 | my_big_array.{(1, ~y:2)} <- 1.5;;
     ^^^^^^^^^^^^
Error: The value my_big_array has type
         (float, Bigarray.float32_elt, Bigarray.c_layout) Bigarray.Array2.t
       but an expression was expected of type ('a, 'b, 'c) Bigarray.Array1.t