go/test/fixedbugs/issue23823.go

// compile

// Copyright 2018 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

// The compiler cannot handle this. Disabled for now.
// See issue #25838.
/*
type I1 = interface {
	I2
}

type I2 interface {
	I1
}
*/
cmd/compile: reintroduce work-around for cyclic alias declarations This change re-introduces (temporarily) a work-around for recursive alias type declarations, originally in https://golang.org/cl/35831/ (intended as fix for #18640). The work-around was removed later for a more comprehensive cycle detection check. That check contained a subtle error which made the code appear to work, while in fact creating incorrect types internally. See #25838 for details. By re-introducing the original work-around, we eliminate problems with many simple recursive type declarations involving aliases; specifically cases such as #27232 and #27267. However, the more general problem remains. This CL also fixes the subtle error (incorrect variable use when analyzing a type cycle) mentioned above and now issues a fatal error with a reference to the relevant issue (rather than crashing later during the compilation). While not great, this is better than the current status. The long-term solution will need to address these cycles (see #25838). As a consequence, several old test cases are not accepted anymore by the compiler since they happened to work accidentally only. This CL disables parts or all code of those test cases. The issues are: #18640, #23823, and #24939. One of the new test cases (fixedbugs/issue27232.go) exposed a go/types issue. The test case is excluded from the go/types test suite and an issue was filed (#28576). Updates #18640. Updates #23823. Updates #24939. Updates #25838. Updates #28576. Fixes #27232. Fixes #27267. Change-Id: I6c2d10da98bfc6f4f445c755fcaab17fc7b214c5 Reviewed-on: https://go-review.googlesource.com/c/147286 Reviewed-by: Matthew Dempsky <mdempsky@google.com> 2018-11-03 00:28:26 -06:00			`// compile`
cmd/compile: correct alias cycle detection The original fix (https://go-review.googlesource.com/c/go/+/35831) for this issue was incorrect as it reported cycles in cases where it shouldn't. Instead, use a different approach: A type cycle containing aliases is only a cycle if there are no type definitions. As soon as there is a type definition, alias expansion terminates and there is no cycle. Approach: Split sprint_depchain into two non-recursive and more easily understandable functions (cycleFor and cycleTrace), and use those instead for cycle reporting. Analyze the cycle returned by cycleFor before issueing an alias cycle error. Also: Removed original fix (main.go) which introduced a separate crash (#23823). Fixes #18640. Fixes #23823. Fixes #24939. Change-Id: Ic3707a9dec40a71dc928a3e49b4868c5fac3d3b7 Reviewed-on: https://go-review.googlesource.com/118078 Reviewed-by: Matthew Dempsky <mdempsky@google.com> 2018-06-06 11:21:15 -06:00
			`// Copyright 2018 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`

cmd/compile: reintroduce work-around for cyclic alias declarations This change re-introduces (temporarily) a work-around for recursive alias type declarations, originally in https://golang.org/cl/35831/ (intended as fix for #18640). The work-around was removed later for a more comprehensive cycle detection check. That check contained a subtle error which made the code appear to work, while in fact creating incorrect types internally. See #25838 for details. By re-introducing the original work-around, we eliminate problems with many simple recursive type declarations involving aliases; specifically cases such as #27232 and #27267. However, the more general problem remains. This CL also fixes the subtle error (incorrect variable use when analyzing a type cycle) mentioned above and now issues a fatal error with a reference to the relevant issue (rather than crashing later during the compilation). While not great, this is better than the current status. The long-term solution will need to address these cycles (see #25838). As a consequence, several old test cases are not accepted anymore by the compiler since they happened to work accidentally only. This CL disables parts or all code of those test cases. The issues are: #18640, #23823, and #24939. One of the new test cases (fixedbugs/issue27232.go) exposed a go/types issue. The test case is excluded from the go/types test suite and an issue was filed (#28576). Updates #18640. Updates #23823. Updates #24939. Updates #25838. Updates #28576. Fixes #27232. Fixes #27267. Change-Id: I6c2d10da98bfc6f4f445c755fcaab17fc7b214c5 Reviewed-on: https://go-review.googlesource.com/c/147286 Reviewed-by: Matthew Dempsky <mdempsky@google.com> 2018-11-03 00:28:26 -06:00			`// The compiler cannot handle this. Disabled for now.`
			`// See issue #25838.`
			`/*`
cmd/compile: correct alias cycle detection The original fix (https://go-review.googlesource.com/c/go/+/35831) for this issue was incorrect as it reported cycles in cases where it shouldn't. Instead, use a different approach: A type cycle containing aliases is only a cycle if there are no type definitions. As soon as there is a type definition, alias expansion terminates and there is no cycle. Approach: Split sprint_depchain into two non-recursive and more easily understandable functions (cycleFor and cycleTrace), and use those instead for cycle reporting. Analyze the cycle returned by cycleFor before issueing an alias cycle error. Also: Removed original fix (main.go) which introduced a separate crash (#23823). Fixes #18640. Fixes #23823. Fixes #24939. Change-Id: Ic3707a9dec40a71dc928a3e49b4868c5fac3d3b7 Reviewed-on: https://go-review.googlesource.com/118078 Reviewed-by: Matthew Dempsky <mdempsky@google.com> 2018-06-06 11:21:15 -06:00			`type I1 = interface {`
			`I2`
			`}`

cmd/compile: reintroduce work-around for cyclic alias declarations This change re-introduces (temporarily) a work-around for recursive alias type declarations, originally in https://golang.org/cl/35831/ (intended as fix for #18640). The work-around was removed later for a more comprehensive cycle detection check. That check contained a subtle error which made the code appear to work, while in fact creating incorrect types internally. See #25838 for details. By re-introducing the original work-around, we eliminate problems with many simple recursive type declarations involving aliases; specifically cases such as #27232 and #27267. However, the more general problem remains. This CL also fixes the subtle error (incorrect variable use when analyzing a type cycle) mentioned above and now issues a fatal error with a reference to the relevant issue (rather than crashing later during the compilation). While not great, this is better than the current status. The long-term solution will need to address these cycles (see #25838). As a consequence, several old test cases are not accepted anymore by the compiler since they happened to work accidentally only. This CL disables parts or all code of those test cases. The issues are: #18640, #23823, and #24939. One of the new test cases (fixedbugs/issue27232.go) exposed a go/types issue. The test case is excluded from the go/types test suite and an issue was filed (#28576). Updates #18640. Updates #23823. Updates #24939. Updates #25838. Updates #28576. Fixes #27232. Fixes #27267. Change-Id: I6c2d10da98bfc6f4f445c755fcaab17fc7b214c5 Reviewed-on: https://go-review.googlesource.com/c/147286 Reviewed-by: Matthew Dempsky <mdempsky@google.com> 2018-11-03 00:28:26 -06:00			`type I2 interface {`
cmd/compile: correct alias cycle detection The original fix (https://go-review.googlesource.com/c/go/+/35831) for this issue was incorrect as it reported cycles in cases where it shouldn't. Instead, use a different approach: A type cycle containing aliases is only a cycle if there are no type definitions. As soon as there is a type definition, alias expansion terminates and there is no cycle. Approach: Split sprint_depchain into two non-recursive and more easily understandable functions (cycleFor and cycleTrace), and use those instead for cycle reporting. Analyze the cycle returned by cycleFor before issueing an alias cycle error. Also: Removed original fix (main.go) which introduced a separate crash (#23823). Fixes #18640. Fixes #23823. Fixes #24939. Change-Id: Ic3707a9dec40a71dc928a3e49b4868c5fac3d3b7 Reviewed-on: https://go-review.googlesource.com/118078 Reviewed-by: Matthew Dempsky <mdempsky@google.com> 2018-06-06 11:21:15 -06:00			`I1`
			`}`
cmd/compile: reintroduce work-around for cyclic alias declarations This change re-introduces (temporarily) a work-around for recursive alias type declarations, originally in https://golang.org/cl/35831/ (intended as fix for #18640). The work-around was removed later for a more comprehensive cycle detection check. That check contained a subtle error which made the code appear to work, while in fact creating incorrect types internally. See #25838 for details. By re-introducing the original work-around, we eliminate problems with many simple recursive type declarations involving aliases; specifically cases such as #27232 and #27267. However, the more general problem remains. This CL also fixes the subtle error (incorrect variable use when analyzing a type cycle) mentioned above and now issues a fatal error with a reference to the relevant issue (rather than crashing later during the compilation). While not great, this is better than the current status. The long-term solution will need to address these cycles (see #25838). As a consequence, several old test cases are not accepted anymore by the compiler since they happened to work accidentally only. This CL disables parts or all code of those test cases. The issues are: #18640, #23823, and #24939. One of the new test cases (fixedbugs/issue27232.go) exposed a go/types issue. The test case is excluded from the go/types test suite and an issue was filed (#28576). Updates #18640. Updates #23823. Updates #24939. Updates #25838. Updates #28576. Fixes #27232. Fixes #27267. Change-Id: I6c2d10da98bfc6f4f445c755fcaab17fc7b214c5 Reviewed-on: https://go-review.googlesource.com/c/147286 Reviewed-by: Matthew Dempsky <mdempsky@google.com> 2018-11-03 00:28:26 -06:00			`*/`