clippy 0.0.208

A bunch of helpful lints to avoid common pitfalls in Rust
error: module has the same name as its containing module
 --> $DIR/module_inception.rs:7:9
  |
7 | /         mod bar {
8 | |             mod foo {}
9 | |         }
  | |_________^
  |
  = note: `-D module-inception` implied by `-D warnings`

error: module has the same name as its containing module
  --> $DIR/module_inception.rs:12:5
   |
12 | /     mod foo {
13 | |         mod bar {}
14 | |     }
   | |_____^

error: aborting due to 2 previous errors