a := b.cacheAction("vet", p, func() *Action {
		a1 := b.CompileAction(mode|ModeVetOnly, depMode, p)

		// vet expects to be able to import "fmt".
		var stk load.ImportStack
		stk.Push("vet")
		p1, err := load.LoadImportWithFlags("fmt", p.Dir, p, &stk, nil, 0)
		if err != nil {
			base.Fatalf("unexpected error loading fmt package from package %s: %v", p.ImportPath, err)
		}
		stk.Pop()
		aFmt := b.CompileAction(ModeBuild, depMode, p1)