15 | panic!("{{{this}}}");
| ^^^^^^^^^^^^
-error: aborting due to 4 previous errors
+error: `unimplemented` should not be present in production code
+ --> $DIR/panic.rs:57:5
+ |
+57 | unimplemented!();
+ | ^^^^^^^^^^^^^^^^^
+ |
+ = note: `-D unimplemented` implied by `-D warnings`
+ = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: aborting due to 5 previous errors