error: Undefined Behavior: callee has fewer arguments than expected
  --> $DIR/too_few_args.rs:LL:CC
   |
LL |     panic!()
   |     ^^^^^^^^ callee has fewer arguments than expected
   |
   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
   = note: backtrace:
   = note: inside `thread_start` at RUSTLIB/std/src/panic.rs:LL:CC
   = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to previous error