error: Undefined Behavior: constructing invalid value: encountered $HEX, but expected a valid unicode scalar value (in `0..=$HEX` but not in `$HEX..=$HEX`) --> $DIR/invalid_char.rs:LL:CC | LL | let _val = match unsafe { std::mem::transmute::(-1) } { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered $HEX, but expected a valid unicode scalar value (in `0..=$HEX` but not in `$HEX..=$HEX`) | = 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 `main` at $DIR/invalid_char.rs:LL:CC note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace error: aborting due to previous error