$ cargo run
   Compiling enums v0.1.0 (file:///projects/enums)
error[E0277]: cannot add `Option<i8>` to `i8`
 --> src/main.rs:5:17
  |
5 |     let sum = x + y;
  |                 ^ no implementation for `i8 + Option<i8>`
  |
  = help: the trait `Add<Option<i8>>` is not implemented for `i8`
help: the following other types implement trait `Add<Rhs>`
 --> /rustc/2d8144b7880597b6e6d3dfd63a9a9efae3f533d3/library/core/src/ops/arith.rs:98:8
  |
  = note: `i8` implements `Add`
 ::: /rustc/2d8144b7880597b6e6d3dfd63a9a9efae3f533d3/library/core/src/ops/arith.rs:113:0
  |
  = note: in this macro invocation
 --> /rustc/2d8144b7880597b6e6d3dfd63a9a9efae3f533d3/library/core/src/internal_macros.rs:22:8
  |
  = note: `&i8` implements `Add<i8>`
 ::: /rustc/2d8144b7880597b6e6d3dfd63a9a9efae3f533d3/library/core/src/internal_macros.rs:33:8
  |
  = note: `i8` implements `Add<&i8>`
 ::: /rustc/2d8144b7880597b6e6d3dfd63a9a9efae3f533d3/library/core/src/internal_macros.rs:44:8
  |
  = note: `&i8` implements `Add`
  = note: this error originates in the macro `add_impl` (in Nightly builds, run with -Z macro-backtrace for more info)

For more information about this error, try `rustc --explain E0277`.
error: could not compile `enums` (bin "enums") due to 1 previous error
