error: cannot declare a new module at this location
 --> src/main.rs:6:5
  |
6 | mod say;
  |     ^^^
  |
note: maybe move this module `src` to its own directory via `src/mod.rs`
 --> src/main.rs:6:5
  |
6 | mod say;
  |     ^^^
note: ... or maybe `use` the module `say` instead of possibly redeclaring it
 --> src/main.rs:6:5
  |
6 | mod say;
  |     ^^^

error: aborting due to previous error