error: constant evaluation is taking a long time
  --> $DIR/issue-70723.rs:1:17
   |
LL | static _X: () = loop {};
   |                 ^^^^^^^
   |
   = note: this lint makes sure the compiler doesn't get stuck due to infinite loops in const eval.
           If your compilation actually takes a long time, you can safely allow the lint.
help: the constant being evaluated
  --> $DIR/issue-70723.rs:1:1
   |
LL | static _X: () = loop {};
   | ^^^^^^^^^^^^^
   = note: `#[deny(long_running_const_eval)]` on by default

error: aborting due to 1 previous error