error: environment variable `__HOPEFULLY_NOT_DEFINED__` not defined
  --> $DIR/extenv-not-defined-default.rs:2:5
   |
LL |     env!("__HOPEFULLY_NOT_DEFINED__");
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: this error originates in the macro `env` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to previous error