panic!("incompatible crate versions");
} else if stderr.contains("failed to run `rustc` to learn about target-specific information") {
panic!("couldn't find librustc_driver, consider setting `LD_LIBRARY_PATH`");
+ } else if stderr.contains("toolchain") && stderr.contains("is not installed") {
+ panic!("missing required toolchain");
}
match output.status.code() {