| Linux in-mum-web1499.main-hosting.eu 5.14.0-503.40.1.el9_5.x86_64 #1 SMP PREEMPT_DYNAMIC Mon May 5 06:06:04 EDT 2025 x86_64 Path : /opt/golang/1.22.0/test/typeparam/ |
| Current File : //opt/golang/1.22.0/test/typeparam/issue52026.go |
// run
// Copyright 2022 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.
package main
func returnOption[T any](n int) Option[T] {
if n == 1 {
return Some[T]{}
} else {
return None{}
}
}
type Option[T any] interface {
sealedOption()
}
type Some[T any] struct {
val T
}
func (s Some[T]) Value() T {
return s.val
}
func (s Some[T]) sealedOption() {}
type None struct{}
func (s None) sealedOption() {}
func main() {
s := returnOption[int](1)
_ = s.(Some[int])
s = returnOption[int](0)
_ = s.(None)
switch (any)(s).(type) {
case Some[int]:
panic("s is a Some[int]")
case None:
// ok
default:
panic("oops")
}
}