Moving on from #11026 (where I was missing args[0]), now I'm seeing this at runtime: ``` $ ./bin/testloop src/demo.rs Error in `stat` on `./.tests_in_loop.exe`: std::io::IoError{kind: OtherIoError, desc: "no such file or directory", detail: None} <<<< building tests >>>> src/demo.rs:1:0: 1:0 error: can't find crate for `std` src/demo.rs:1 #[feature(non_ascii_idents)]; ^ task 'rustc' failed at 'explicit failure', /Users/kevin/code/rust/src/libsyntax/diagnostic.rs:76 task '<main>' failed at 'explicit failure', /Users/kevin/code/rust/src/librustc/lib.rs:398 ``` Where `testloop` is my program calling `rustc::main_args` (and trying to build `demo.rs`)... cc @alexcrichton