error: constant evaluation is taking a long time
  --> $DIR/ctfe-recursion.rs:9:9
   |
LL |         recurse(n - 1)
   |         ^^^^^^^^^^^^^^
   |
   = 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/ctfe-recursion.rs:13:1
   |
LL | const X: u32 = recurse(19);
   | ^^^^^^^^^^^^
   = note: `#[deny(long_running_const_eval)]` on by default

error: aborting due to 1 previous error