https://github.com/sourcefrog/cargo-mutants/blob/3dd69896d3fbfd9181e66f5d5965a19ace2a3874/tests/util/mod.rs#L27 `cargo_bin` relies on implementation details of cargo that will soon break (rust-lang/cargo#16147, rust-lang/cargo#15010). You can test this by running: ``` CARGO_BUILD_BUILD_DIR="{cargo-cache-home}/build/{workspace-path-hash}" cargo test ``` The replacement is `assert_cmd::cargo_bin!`