return
			}
			for _, dep := range ldDeps {
				addImport(dep, false)
			}
		}
	}

	// Check for case-insensitive collisions of import paths.
	// If modifying, consider changing checkPathCollisions() in
	// src/cmd/go/internal/modcmd/vendor.go
	fold := str.ToFold(p.ImportPath)
	if other := foldPath[fold]; other == "" {
		foldPath[fold] = p.ImportPath
	} else if other != p.ImportPath {