Currently, when the version output isn't recognized, rustc_version gives an error like this:

thread 'main' panicked at 'failed to determine underlying rustc version of Miri: UnexpectedVersionFormat', src/tools/miri/cargo-miri/bin.rs:132:38

However this is very unhelpful for determining the actual issue, which is that the dynamic libraries were not set up correctly:

/home/r/src/rust/rustc.3/build/x86_64-unknown-linux-gnu/stage0-tools-bin/miri: error while loading shared libraries: libLLVM-11-rust-1.49.0-nightly.so: cannot open shared object file: No such file or directory

It would be great to either print the full output of the command on failure, or to store it in the error message so the library user can report it themselves.