error[E0658]: allow_internal_unstable side-steps feature gating and stability checks
  --> $DIR/feature-gate-allow-internal-unstable-struct.rs:6:1
   |
LL | #[allow_internal_unstable(something)]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: add `#![feature(allow_internal_unstable)]` to the crate attributes to enable
   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date

error: `#[allow_internal_unstable]` attribute cannot be used on structs
  --> $DIR/feature-gate-allow-internal-unstable-struct.rs:6:1
   |
LL | #[allow_internal_unstable(something)]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: `#[allow_internal_unstable]` can be applied to macro defs and functions

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0658`.