go/test/typeparam/issue50259.go

// compile

// Copyright 2022 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

var x T[B]

type T[_ any] struct{}
type A T[B]
type B = T[A]
all: avoid use of cmd/compile -G flag in tests The next CL will remove the -G flag, effectively hard-coding it to its current default (-G=3). Change-Id: Ib4743b529206928f9f1cca9fdb19989728327831 Reviewed-on: https://go-review.googlesource.com/c/go/+/388534 Reviewed-by: Keith Randall <khr@golang.org> Trust: Matthew Dempsky <mdempsky@google.com> Run-TryBot: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> 2022-02-28 22:32:19 +00:00			`// compile`
go/types, types2: report an error when using a broken alias The type checker doesn't have a general mechanism to "use" the type of a type alias whose type depends on a recursive type declaration which is not yet completely type-checked. In some cases, the type of a type alias is needed before it is determined; the type is incorrect (invalid) in that case but no error is reported. The type-checker is happy with this (incorrect type), but the compiler may crash under some circumstances. A correct fix will likely require some form of forwarding type which is a fairly pervasive change and may also affect the type checker API. This CL introduces a simple side table, a map of broken type aliases, which is consulted before the type associated with a type alias is used. If the type alias is broken, an error is reported. This is a stop-gap solution that prevents the compiler from crashing. The reported error refers to the corresponding issue which suggests a work-around that may be applicable in some cases. Also fix a minor error related to type cycles: If we have a cycle that doesn't start with a type, don't use a compiler error message that explicitly mentions "type". Fixes #50259. Fixes #50276. Fixes #50779. For #50729. Change-Id: Ie8e38f49ef724e742e8e78625e6d4f3d4014a52c Reviewed-on: https://go-review.googlesource.com/c/go/+/379916 Trust: Robert Griesemer <gri@golang.org> Run-TryBot: Robert Griesemer <gri@golang.org> Reviewed-by: Robert Findley <rfindley@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> 2022-01-21 02:56:57 +00:00
			`// Copyright 2022 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`

			`var x T[B]`

			`type T[_ any] struct{}`
go/types, types2: reorder object processing to avoid broken aliases By processing non-alias type declarations before alias type declaration, and those before everything else we can avoid some of the remaining errors which are due to alias types not being available. For #25838. For #50259. For #50276. For #50729. Change-Id: I233da2899a6d4954c239638624dfa8c08662e6b9 Reviewed-on: https://go-review.googlesource.com/c/go/+/380056 Trust: Robert Griesemer <gri@golang.org> Run-TryBot: Robert Griesemer <gri@golang.org> Reviewed-by: Robert Findley <rfindley@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> 2022-01-21 17:05:51 +00:00			`type A T[B]`
go/types, types2: report an error when using a broken alias The type checker doesn't have a general mechanism to "use" the type of a type alias whose type depends on a recursive type declaration which is not yet completely type-checked. In some cases, the type of a type alias is needed before it is determined; the type is incorrect (invalid) in that case but no error is reported. The type-checker is happy with this (incorrect type), but the compiler may crash under some circumstances. A correct fix will likely require some form of forwarding type which is a fairly pervasive change and may also affect the type checker API. This CL introduces a simple side table, a map of broken type aliases, which is consulted before the type associated with a type alias is used. If the type alias is broken, an error is reported. This is a stop-gap solution that prevents the compiler from crashing. The reported error refers to the corresponding issue which suggests a work-around that may be applicable in some cases. Also fix a minor error related to type cycles: If we have a cycle that doesn't start with a type, don't use a compiler error message that explicitly mentions "type". Fixes #50259. Fixes #50276. Fixes #50779. For #50729. Change-Id: Ie8e38f49ef724e742e8e78625e6d4f3d4014a52c Reviewed-on: https://go-review.googlesource.com/c/go/+/379916 Trust: Robert Griesemer <gri@golang.org> Run-TryBot: Robert Griesemer <gri@golang.org> Reviewed-by: Robert Findley <rfindley@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> 2022-01-21 02:56:57 +00:00			`type B = T[A]`