// the package path is malformed (for example, the path contains "mod/" or "@").
//
// loadPackageData returns a boolean, loaded, which is true if this is the
// first time the package was loaded. Callers may preload imports in this case.
func loadPackageData(ctx context.Context, path, parentPath, parentDir, parentRoot string, parentIsStd bool, mode int) (bp *build.Package, loaded bool, err error) {