error[E0308]: cannot coerce intrinsics to function pointers
  --> $DIR/reify-intrinsic.rs:6:64
   |
LL |     let _: unsafe extern "rust-intrinsic" fn(isize) -> usize = std::mem::transmute;
   |            -------------------------------------------------   ^^^^^^^^^^^^^^^^^^^ cannot coerce intrinsics to function pointers
   |            |
   |            expected due to this
   |
   = note: expected fn pointer `unsafe extern "rust-intrinsic" fn(isize) -> usize`
                 found fn item `unsafe extern "rust-intrinsic" fn(_) -> _ {transmute::<_, _>}`
help: use parentheses to call this function
   |
LL |     let _: unsafe extern "rust-intrinsic" fn(isize) -> usize = std::mem::transmute(...);
   |                                                                                   ^^^^^

error[E0606]: casting `unsafe extern "rust-intrinsic" fn(_) -> _ {transmute::<_, _>}` as `unsafe extern "rust-intrinsic" fn(isize) -> usize` is invalid
  --> $DIR/reify-intrinsic.rs:11:13
   |
LL |     let _ = std::mem::transmute as unsafe extern "rust-intrinsic" fn(isize) -> usize;
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0308, E0606.
For more information about an error, try `rustc --explain E0308`.