error[E0658]: mutable by-reference bindings are experimental
  --> $DIR/feature-gate-mut-ref.rs:2:17
   |
LL |     let mut ref x = 10;
   |                 ^
   |
   = note: see issue #123076 <https://github.com/rust-lang/rust/issues/123076> for more information
   = help: add `#![feature(mut_ref)]` 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   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date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[E0658]: mutable by-reference bindings are experimental
  --> $DIR/feature-gate-mut-ref.rs:6:21
   |
LL |     let mut ref mut z = 14;
   |                     ^
   |
   = note: see issue #123076 <https://github.com/rust-lang/rust/issues/123076> for more information
   = help: add `#![feature(mut_ref)]` 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   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date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[E0658]: mutable by-reference bindings are experimental
  --> $DIR/feature-gate-mut-ref.rs:10:17
   |
LL |     let mut ref x = 10;
   |                 ^
   |
   = note: see issue #123076 <https://github.com/rust-lang/rust/issues/123076> for more information
   = help: add `#![feature(mut_ref)]` 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   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date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[E0658]: mutable by-reference bindings are experimental
  --> $DIR/feature-gate-mut-ref.rs:12:21
   |
LL |     let mut ref mut y = 10;
   |                     ^
   |
   = note: see issue #123076 <https://github.com/rust-lang/rust/issues/123076> for more information
   = help: add `#![feature(mut_ref)]` 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   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date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: aborting due to 4 previous errors

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