mirror of
https://github.com/golang/go
synced 2024-11-22 22:40:02 -07:00
807c80fce3
We shouldn't use CONVNOP for conversions between two different nonempty interface types, because we want to update the itab in those situations. Fixes #18595 After this CL, we are guaranteed that itabs are unique, that is there is only one itab per compile-time-type/concrete type pair. See also the tests in CL 35115 and 35116 which make sure this invariant holds even for shared libraries and plugins. Unique itabs are required for CL 34810 (faster type switch code). R=go1.9 Change-Id: Id27d2e01ded706680965e4cb69d7c7a24ac2161b Reviewed-on: https://go-review.googlesource.com/35119 Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>
54 lines
867 B
Go
54 lines
867 B
Go
// run
|
|
|
|
// Copyright 2017 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.
|
|
|
|
// This test makes sure that itabs are unique.
|
|
// More explicitly, we require that only one itab structure exists for the pair of
|
|
// a given compile-time interface type and underlying concrete type.
|
|
// Ensuring this invariant enables fixes for 18492 (improve type switch code).
|
|
|
|
package main
|
|
|
|
type I interface {
|
|
M()
|
|
}
|
|
type J interface {
|
|
M()
|
|
}
|
|
|
|
type T struct{}
|
|
|
|
func (*T) M() {}
|
|
|
|
func main() {
|
|
test1()
|
|
test2()
|
|
}
|
|
|
|
func test1() {
|
|
t := new(T)
|
|
var i1, i2 I
|
|
var j interface {
|
|
M()
|
|
}
|
|
i1 = t
|
|
j = t
|
|
i2 = j
|
|
if i1 != i2 {
|
|
panic("interfaces not equal")
|
|
}
|
|
}
|
|
|
|
func test2() {
|
|
t := new(T)
|
|
i1 := (I)(t)
|
|
i2 := (I)((interface {
|
|
M()
|
|
})((J)(t)))
|
|
if i1 != i2 {
|
|
panic("interfaces not equal")
|
|
}
|
|
}
|