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// run -gcflags=-G=3
// 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.
package main
func f[T any](x interface{}) T {
return x.(T)
}
func f2[T any](x interface{}) (T, bool) {
t, ok := x.(T)
return t, ok
}
type I interface {
foo()
}
type myint int
func (myint) foo() {
}
type myfloat float64
func (myfloat) foo() {
}
func g[T I](x I) T {
return x.(T)
}
func g2[T I](x I) (T, bool) {
t, ok := x.(T)
return t, ok
}
func h[T any](x interface{}) struct{ a, b T } {
return x.(struct{ a, b T })
}
func k[T any](x interface{}) interface{ bar() T } {
return x.(interface{ bar() T })
}
type mybar int
func (x mybar) bar() int {
return int(x)
}
func main() {
var i interface{} = int(3)
var j I = myint(3)
var x interface{} = float64(3)
var y I = myfloat(3)
println(f[int](i))
shouldpanic(func() { f[int](x) })
println(f2[int](i))
println(f2[int](x))
println(g[myint](j))
shouldpanic(func() { g[myint](y) })
println(g2[myint](j))
println(g2[myint](y))
println(h[int](struct{ a, b int }{3, 5}).a)
println(k[int](mybar(3)).bar())
type large struct {a,b,c,d,e,f int}
println(f[large](large{}).a)
l2, ok := f2[large](large{})
println(l2.a, ok)
}
func shouldpanic(x func()) {
defer func() {
e := recover()
if e == nil {
panic("didn't panic")
}
}()
x()
}
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