w := bufio.NewWriter(os.Stdout)
	defer w.Flush()

	format := func(m module.Version) {
		w.WriteString(m.Path)
		if m.Version != "" {
			w.WriteString("@")
			w.WriteString(m.Version)
		}
	}

	mg.WalkBreadthFirst(func(m module.Version) {
		reqs, _ := mg.RequiredBy(m)
		for _, r := range reqs {
			format(m)
			w.WriteByte(' ')
			format(r)
			w.WriteByte('\n')
		}
	})

		}
	}
	gover.ModSort(list[len(uniqueRoots):])

	return list
}

// WalkBreadthFirst invokes f once, in breadth-first order, for each module
// version other than "none" that appears in the graph, regardless of whether
// that version is selected.
func (g *Graph) WalkBreadthFirst(f func(m module.Version)) {
	var queue []module.Version
	enqueued := make(map[module.Version]bool)

	return mg.g.Selected(path)
}

// WalkBreadthFirst invokes f once, in breadth-first order, for each module
// version other than "none" that appears in the graph, regardless of whether
// that version is selected.
func (mg *ModuleGraph) WalkBreadthFirst(f func(m module.Version)) {
	mg.g.WalkBreadthFirst(f)
}

// BuildList returns the selected versions of all modules present in the graph,

			extendedRootPruning[m] = findPruning(m)
		}

		// Now check the resulting extended graph for errors and incompatibilities.
		t := dqTracker{extendedRootPruning: extendedRootPruning}
		mg.g.WalkBreadthFirst(func(m module.Version) {
			if max, ok := mustSelectVersion[m.Path]; ok && gover.ModCompare(m.Path, m.Version, max) > 0 {
				// m itself violates mustSelect, so it cannot appear in the module graph

			r := resolveReplacement(m)
			keep[modkey(r)] = true
			if which == addBuildListZipSums {
				keep[r] = true
			}
		}
	} else {
		mg, _ := rs.Graph(ctx)
		mg.WalkBreadthFirst(func(m module.Version) {
			if _, ok := mg.RequiredBy(m); ok {
				// The requirements from m's go.mod file are present in the module graph,
				// so they are relevant to the MVS result regardless of whether m was