);
if project.license_file.is_some() && project.license.is_some() {
manifest.warnings_mut().add_warning(
- "only one of `license` or \
- `license-file` is necessary"
+ "only one of `license` or `license-file` is necessary\n\
+ `license` should be used if the package license can be expressed \
+ with a standard SPDX expression.\n\
+ `license-file` should be used if the package uses a non-standard license.\n\
+ See https://doc.rust-lang.org/cargo/reference/manifest.html#the-license-and-license-file-fields \
+ for more information."
.to_string(),
);
}