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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>
This commit is contained in:
parent
fe85c24431
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@ -656,25 +656,31 @@ func (check *Checker) packageObjects() {
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}
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}
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// We process non-alias declarations first, in order to avoid situations where
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// the type of an alias declaration is needed before it is available. In general
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// this is still not enough, as it is possible to create sufficiently convoluted
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// recursive type definitions that will cause a type alias to be needed before it
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// is available (see issue #25838 for examples).
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// As an aside, the cmd/compiler suffers from the same problem (#25838).
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// We process non-alias type declarations first, followed by alias declarations,
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// and then everything else. This appears to avoid most situations where the type
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// of an alias is needed before it is available.
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// There may still be cases where this is not good enough (see also issue #25838).
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// In those cases Checker.ident will report an error ("invalid use of type alias").
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var aliasList []*TypeName
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// phase 1
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var othersList []Object // everything that's not a type
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// phase 1: non-alias type declarations
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for _, obj := range objList {
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// If we have a type alias, collect it for the 2nd phase.
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if tname, _ := obj.(*TypeName); tname != nil && check.objMap[tname].tdecl.Alias {
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aliasList = append(aliasList, tname)
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continue
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if tname, _ := obj.(*TypeName); tname != nil {
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if check.objMap[tname].tdecl.Alias {
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aliasList = append(aliasList, tname)
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} else {
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check.objDecl(obj, nil)
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}
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} else {
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othersList = append(othersList, obj)
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}
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}
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// phase 2: alias type declarations
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for _, obj := range aliasList {
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check.objDecl(obj, nil)
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}
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// phase 2
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for _, obj := range aliasList {
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// phase 3: all other declarations
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for _, obj := range othersList {
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check.objDecl(obj, nil)
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}
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26
src/cmd/compile/internal/types2/testdata/fixedbugs/issue25838.go
vendored
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26
src/cmd/compile/internal/types2/testdata/fixedbugs/issue25838.go
vendored
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@ -0,0 +1,26 @@
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// Copyright 2022 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package p
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// examples from the issue
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type (
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e = f
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f = g
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g = []h
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h i
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i = j
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j = e
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)
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type (
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e1 = []h1
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h1 e1
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)
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type (
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P = *T
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T P
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)
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@ -7,7 +7,7 @@ package p
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var x T[B]
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type T[_ any] struct{}
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type A T[B /* ERROR invalid use of type alias */ ]
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type A T[B]
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type B = T[A]
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// test case from issue
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@ -15,4 +15,4 @@ type B = T[A]
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var v Box[Step]
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type Box[T any] struct{}
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type Step = Box[StepBox]
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type StepBox Box[Step /* ERROR invalid use of type alias */ ]
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type StepBox Box[Step]
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@ -11,7 +11,7 @@ type pair[S any] struct {}
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var _ transform[step]
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type box transform[step /* ERROR invalid use of type alias */ ]
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type box transform[step]
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type step = pair[box]
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// test case from issue
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@ -27,7 +27,7 @@ var first Transform[Step]
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// This line doesn't use the Step alias, and it compiles fine if you uncomment it.
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var second Transform[Pair[Box, interface{}]]
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type Box *Transform[Step /* ERROR invalid use of type alias */ ]
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type Box *Transform[Step]
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// This line is the same as the `first` line, but it comes after the Box declaration and
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// does not break the compile.
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@ -629,25 +629,31 @@ func (check *Checker) packageObjects() {
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}
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}
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// We process non-alias declarations first, in order to avoid situations where
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// the type of an alias declaration is needed before it is available. In general
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// this is still not enough, as it is possible to create sufficiently convoluted
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// recursive type definitions that will cause a type alias to be needed before it
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// is available (see issue #25838 for examples).
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// As an aside, the cmd/compiler suffers from the same problem (#25838).
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// We process non-alias type declarations first, followed by alias declarations,
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// and then everything else. This appears to avoid most situations where the type
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// of an alias is needed before it is available.
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// There may still be cases where this is not good enough (see also issue #25838).
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// In those cases Checker.ident will report an error ("invalid use of type alias").
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var aliasList []*TypeName
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// phase 1
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var othersList []Object // everything that's not a type
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// phase 1: non-alias type declarations
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for _, obj := range objList {
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// If we have a type alias, collect it for the 2nd phase.
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if tname, _ := obj.(*TypeName); tname != nil && check.objMap[tname].tdecl.Assign.IsValid() {
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aliasList = append(aliasList, tname)
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continue
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if tname, _ := obj.(*TypeName); tname != nil {
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if check.objMap[tname].tdecl.Assign.IsValid() {
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aliasList = append(aliasList, tname)
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} else {
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check.objDecl(obj, nil)
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}
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} else {
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othersList = append(othersList, obj)
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}
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}
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// phase 2: alias type declarations
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for _, obj := range aliasList {
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check.objDecl(obj, nil)
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}
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// phase 2
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for _, obj := range aliasList {
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// phase 3: all other declarations
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for _, obj := range othersList {
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check.objDecl(obj, nil)
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}
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26
src/go/types/testdata/fixedbugs/issue25838.go
vendored
Normal file
26
src/go/types/testdata/fixedbugs/issue25838.go
vendored
Normal file
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@ -0,0 +1,26 @@
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// Copyright 2022 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package p
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// examples from the issue
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type (
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e = f
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f = g
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g = []h
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h i
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i = j
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j = e
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)
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type (
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e1 = []h1
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h1 e1
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)
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type (
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P = *T
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T P
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)
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@ -7,7 +7,7 @@ package p
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var x T[B]
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type T[_ any] struct{}
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type A T[B /* ERROR invalid use of type alias */ ]
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type A T[B]
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type B = T[A]
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// test case from issue
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@ -15,4 +15,4 @@ type B = T[A]
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var v Box[Step]
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type Box[T any] struct{}
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type Step = Box[StepBox]
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type StepBox Box[Step /* ERROR invalid use of type alias */ ]
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type StepBox Box[Step]
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@ -11,7 +11,7 @@ type pair[S any] struct {}
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var _ transform[step]
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type box transform[step /* ERROR invalid use of type alias */ ]
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type box transform[step]
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type step = pair[box]
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// test case from issue
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@ -27,7 +27,7 @@ var first Transform[Step]
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// This line doesn't use the Step alias, and it compiles fine if you uncomment it.
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var second Transform[Pair[Box, interface{}]]
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type Box *Transform[Step /* ERROR invalid use of type alias */ ]
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type Box *Transform[Step]
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// This line is the same as the `first` line, but it comes after the Box declaration and
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// does not break the compile.
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@ -1,4 +1,4 @@
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// errorcheck -G=3
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// compile -G=3
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// Copyright 2022 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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@ -9,5 +9,5 @@ package p
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var x T[B]
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type T[_ any] struct{}
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type A T[B] // ERROR "invalid use of type alias B in recursive type"
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type A T[B]
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type B = T[A]
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