golang cycles4 代码
文件路径：/src/cmd/compile/internal/types2/testdata/check/cycles4.go
/ Copyright 2013 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 p
import "unsafe"
/ Check that all methods of T are collected before
/ determining the result type of m (which embeds
/ all methods of T).
type T interface {
m() interface {T}
E
}
var _ int = T.m(nil).m().e()
type E interface {
e() int
}
/ Check that unresolved forward chains are followed
/ (see also comment in resolver.go, checker.typeDecl).
var _ int = C.m(nil).m().e()
type A B
type B interface {
m() interface{C}
E
}
type C A
/ Check that interface type comparison for identity
/ does not recur endlessly.
type T1 interface {
m() interface{T1}
}
type T2 interface {
m() interface{T2}
}
func _(x T1, y T2) {
/ Checking for assignability of interfaces must check
/ if all methods of x are present in y, and that they
/ have identical signatures. The signatures recur via
/ the result type, which is an interface that embeds
/ a single method m that refers to the very interface
/ that contains it. This requires cycle detection in
/ identity checks for interface types.
x = y
}
type T3 interface {
m() interface{T4}
}
type T4 interface {
m() interface{T3}
}
func _(x T1, y T3) {
x = y
}
/ Check that interfaces are type-checked in order of
/ (embedded interface) dependencies (was issue 7158).
var x1 T5 = T7(nil)
type T5 interface {
T6
}
type T6 interface {
m() T7
}
type T7 interface {
T5
}
/ Actual test case from issue 7158.
func wrapNode() Node {
return wrapElement()
}
func wrapElement() Element {
return nil
}
type EventTarget interface {
AddEventListener(Event)
}
type Node interface {
EventTarget
}
type Element interface {
Node
}
type Event interface {
Target() Element
}
/ Check that accessing an interface method too early doesn't lead
/ to follow-on errors due to an incorrectly computed type set.
type T8 interface {
m() [unsafe.Sizeof(T8.m /* ERROR undefined */ )]int
}
var _ = T8.m / no error expected here