* `lock_update`: cargo will want to update `Cargo.lock`. (The `-u` and `-U` options override this.)
* `online`: this subcommand makes no sense to run offline. (The `-o` and `-O` options, and the configuration, can override this.)
* `edits`: The purpose of this subcommand is to edit the source tree. Produces warning if `--edit-sources` mode not specified.
+ * `creates`: The purpose of this subcommand is to edit the source tree and create new files in it. Produces warning if `--edit-sources` (`-E`) mode not specified twice.
* `!target`: cargo would reject `--target=<arch>`; in this case nailing-cargo's `-T` option is ineffective.
* `!target-dir`: cargo would reject `--target-dir`, so don't pass it. (Usually we pass `--target-dir=target` when we pass `--manifest-path`, since cargo's default is `target` in the same directory as `Cargo.toml`.)
* `linkfarm-shallow`: Make the default be `--linkfarm=shallow`. This is the default for `miri` and can also be used for other subcommands which do not understandg `--manifest-path` properly.