Function find_workspace_root_with_membership_check 

pub fn find_workspace_root_with_membership_check(
    manifest_path: &Path,
    gctx: &GlobalContext,
) -> CargoResult<Option<PathBuf>>

Finds the workspace root for a manifest, with minimal verification.

This is similar to find_workspace_root, but additionally verifies that the package and workspace agree on each other:

• If the package has an explicit package.workspace pointer, it is trusted
• Otherwise, the workspace must include the package in its members list