golang a 代码
文件路径：/test/closure5.dir/a.go
/ Copyright 2021 The Go Authors. All rights reserved.
/ Use of this source code is governed by a BSD-style
/ license that can be found in the LICENSE file.
/ Check correctness of various closure corner cases
/ that are expected to be inlined
package a
func f() bool { return true }
func G() func() func() bool { return func() func() bool { return f } }