error[E0723]: can only call other `const fn` within a `const fn`, but `const std::intrinsics::transmute::<u32, i32>` is not stable as `const fn`
  --> $DIR/internal-unstable-const.rs:11:14
   |
LL |     unsafe { std::mem::transmute(4u32) }
   |              ^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #57563 <https://github.com/rust-lang/rust/issues/57563> for more information
   = help: add `#![feature(const_fn)]` to the crate attributes to enable

error: aborting due to previous error

For more information about this error, try `rustc --explain E0723`.