go/test/fixedbugs/bug398.go
Matthew Dempsky 840b346c5d cmd/compile: reject anonymous interface cycles
This CL changes cmd/compile to reject anonymous interface cycles like:

	type I interface { m() interface { I } }

We don't anticipate any users to be affected by this change in
practice. Nonetheless, this CL also adds a `-d=interfacecycles`
compiler flag to suppress the error. And assuming no issue reports
from users, we'll move the check into go/types and types2 instead.

Updates #56103.

Change-Id: I1f1dce2d7aa19fb388312cc020e99cc354afddcb
Reviewed-on: https://go-review.googlesource.com/c/go/+/445598
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
2022-11-21 20:15:23 +00:00

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679 B
Go

// compile -d=interfacecycles
// Copyright 2012 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.
// Used to crash compiler in interface type equality check.
// (This test used to have problems - see #15596.)
package p
// exported interfaces
type I1 interface {
F() interface{I1}
}
type I2 interface {
F() interface{I2}
}
var V1 I1
var V2 I2
func F() bool {
return V1 == V2
}
// non-exported interfaces
type i1 interface {
F() interface{i1}
}
type i2 interface {
F() interface{i2}
}
var v1 i1
var v2 i2
func f() bool {
return v1 == v2
}