error[E0432]: unresolved import `core`
  --> $DIR/feature-gate-extern_absolute_paths.rs:1:5
   |
LL | use core::default;
   |     ^^^^ maybe a missing crate `core`?
   |
   = help: consider adding `extern crate core` to use the `core` crate

error[E0433]: failed to resolve: maybe a missing crate `core`?
  --> $DIR/feature-gate-extern_absolute_paths.rs:4:19
   |
LL |     let _: u8 = ::core::default::Default();
   |                   ^^^^ maybe a missing crate `core`?
   |
   = help: consider adding `extern crate core` to use the `core` crate

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0432, E0433.
For more information about an error, try `rustc --explain E0432`.