src/doc/book/listings/ch15-smart-pointers/listing-15-03/output.txt

   1 $ cargo run
   2    Compiling cons-list v0.1.0 (file:///projects/cons-list)
   3 error[E0072]: recursive type `List` has infinite size
   4  --> src/main.rs:1:1
   5   |
   6 1 | enum List {
   7   | ^^^^^^^^^ recursive type has infinite size
   8 2 |     Cons(i32, List),
   9   |               ---- recursive without indirection
  10   |
  11 help: insert some indirection (e.g., a `Box`, `Rc`, or `&`) to make `List` representable
  12   |
  13 2 |     Cons(i32, Box<List>),
  14   |               ^^^^    ^
  15
  16 error[E0391]: cycle detected when computing drop-check constraints for `List`
  17  --> src/main.rs:1:1
  18   |
  19 1 | enum List {
  20   | ^^^^^^^^^
  21   |
  22   = note: ...which again requires computing drop-check constraints for `List`, completing the cycle
  23   = note: cycle used when computing dropck types for `Canonical { max_universe: U0, variables: [], value: ParamEnvAnd { param_env: ParamEnv { caller_bounds: [], reveal: UserFacing }, value: List } }`
  24
  25 error: aborting due to 2 previous errors
  26
  27 Some errors have detailed explanations: E0072, E0391.
  28 For more information about an error, try `rustc --explain E0072`.
  29 error: could not compile `cons-list`
  30
  31 To learn more, run the command again with --verbose.