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