mirror of
https://github.com/golang/go
synced 2024-09-04 23:44:16 +00:00
f4f503e0a3
Introduce new dynamic dottype operations which take a dynamic instead of static type to convert to. Change-Id: I5824a1fea056fe811b1226ce059e1e8da1baa335 Reviewed-on: https://go-review.googlesource.com/c/go/+/337609 Trust: Keith Randall <khr@golang.org> Trust: Dan Scales <danscales@google.com> Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Dan Scales <danscales@google.com>
87 lines
1.4 KiB
Go
87 lines
1.4 KiB
Go
// run -gcflags=-G=3
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// Copyright 2021 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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func f[T any](x interface{}) T {
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return x.(T)
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}
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func f2[T any](x interface{}) (T, bool) {
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t, ok := x.(T)
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return t, ok
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}
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type I interface {
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foo()
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}
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type myint int
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func (myint) foo() {
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}
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type myfloat float64
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func (myfloat) foo() {
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}
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func g[T I](x I) T {
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return x.(T)
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}
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func g2[T I](x I) (T, bool) {
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t, ok := x.(T)
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return t, ok
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}
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func h[T any](x interface{}) struct{ a, b T } {
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return x.(struct{ a, b T })
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}
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func k[T any](x interface{}) interface{ bar() T } {
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return x.(interface{ bar() T })
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}
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type mybar int
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func (x mybar) bar() int {
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return int(x)
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}
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func main() {
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var i interface{} = int(3)
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var j I = myint(3)
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var x interface{} = float64(3)
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var y I = myfloat(3)
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println(f[int](i))
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shouldpanic(func() { f[int](x) })
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println(f2[int](i))
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println(f2[int](x))
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println(g[myint](j))
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shouldpanic(func() { g[myint](y) })
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println(g2[myint](j))
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println(g2[myint](y))
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println(h[int](struct{ a, b int }{3, 5}).a)
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println(k[int](mybar(3)).bar())
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type large struct {a,b,c,d,e,f int}
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println(f[large](large{}).a)
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l2, ok := f2[large](large{})
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println(l2.a, ok)
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}
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func shouldpanic(x func()) {
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defer func() {
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e := recover()
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if e == nil {
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panic("didn't panic")
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}
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}()
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x()
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}
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