values := f.NamedValues[*name]
		for i, v := range values {
			if v.Op == OpCopy {
				values[i] = v.Args[0]
			}
		}
	}
}

// copySource returns the (non-copy) op which is the
// ultimate source of v.  v must be a copy op.
func copySource(v *Value) *Value {
	w := v.Args[0]

	// This loop is just:
	// for w.Op == OpCopy {
	//     w = w.Args[0]
	// }
	// but we take some extra care to make sure we

func (b *Builder) Copy() *Builder {
	return &Builder{
		t:             b.t,
		needFrom:      copySources(b.needFrom),
		needTo:        copySources(b.needTo),
		needFromAndTo: copySources(b.needFromAndTo),
		complete:      copySources(b.complete),
		out:           b.out.Copy(),
		yamlCount:     b.yamlCount,
	}
}

func copySources(sources []Source) []Source {
	return append([]Source{}, sources...)