From a991d9dc27bda23018e23488806c8f8d027e4f7b Mon Sep 17 00:00:00 2001 From: Dan Scales Date: Wed, 26 Jan 2022 17:58:08 -0800 Subject: [PATCH] cmd/compile: add missing shape check in (*Tsubster).tinter Add a missing shape check in (*Tsubster).tinter when substituting on a generic type which is an empty interface, analogous to same check in (*Tsubster).tstruct. Empty structs/interfaces that have rparams (i.e. are a generic type or a shape type) need to get a new type of their rparams - they will be different even though they don't have any fields/methods. Without this shape check, we were not correctly completing the Token[int] type during substitution in the example in the issue. This issue only happens for a generic type which is an empty interface (i.e. doesn't actually use the type param, hence quite unusual). Added the test case already created by Keith. Fixes #50841 Change-Id: Ia985b9f52c0e87ed0647b46373e44c51cb748ba4 Reviewed-on: https://go-review.googlesource.com/c/go/+/381175 Trust: Dan Scales Run-TryBot: Dan Scales TryBot-Result: Gopher Robot Reviewed-by: Keith Randall --- src/cmd/compile/internal/typecheck/subr.go | 14 +++++++------- test/typeparam/issue50841.dir/a.go | 22 ++++++++++++++++++++++ test/typeparam/issue50841.dir/b.go | 11 +++++++++++ test/typeparam/issue50841.go | 7 +++++++ 4 files changed, 47 insertions(+), 7 deletions(-) create mode 100644 test/typeparam/issue50841.dir/a.go create mode 100644 test/typeparam/issue50841.dir/b.go create mode 100644 test/typeparam/issue50841.go diff --git a/src/cmd/compile/internal/typecheck/subr.go b/src/cmd/compile/internal/typecheck/subr.go index ac90d87f26..93812ebda5 100644 --- a/src/cmd/compile/internal/typecheck/subr.go +++ b/src/cmd/compile/internal/typecheck/subr.go @@ -1326,9 +1326,9 @@ func (ts *Tsubster) typ1(t *types.Type) *types.Type { func (ts *Tsubster) tstruct(t *types.Type, force bool) *types.Type { if t.NumFields() == 0 { if t.HasTParam() || t.HasShape() { - // For an empty struct, we need to return a new type, - // since it may now be fully instantiated (HasTParam - // becomes false). + // For an empty struct, we need to return a new type, if + // substituting from a generic type or shape type, since it + // will change HasTParam/HasShape flags. return types.NewStruct(t.Pkg(), nil) } return t @@ -1387,10 +1387,10 @@ func (ts *Tsubster) tstruct(t *types.Type, force bool) *types.Type { // tinter substitutes type params in types of the methods of an interface type. func (ts *Tsubster) tinter(t *types.Type, force bool) *types.Type { if t.Methods().Len() == 0 { - if t.HasTParam() { - // For an empty interface, we need to return a new type, - // since it may now be fully instantiated (HasTParam - // becomes false). + if t.HasTParam() || t.HasShape() { + // For an empty interface, we need to return a new type, if + // substituting from a generic type or shape type, since + // since it will change HasTParam/HasShape flags. return types.NewInterface(t.Pkg(), nil, false) } return t diff --git a/test/typeparam/issue50841.dir/a.go b/test/typeparam/issue50841.dir/a.go new file mode 100644 index 0000000000..37e0233701 --- /dev/null +++ b/test/typeparam/issue50841.dir/a.go @@ -0,0 +1,22 @@ +// 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 a + +func Marshal[foobar any]() { + _ = NewEncoder[foobar]() +} + +func NewEncoder[foobar any]() *Encoder[foobar] { + return nil +} + +type Encoder[foobar any] struct { +} + +func (e *Encoder[foobar]) EncodeToken(t Token[foobar]) { + +} + +type Token[foobar any] any diff --git a/test/typeparam/issue50841.dir/b.go b/test/typeparam/issue50841.dir/b.go new file mode 100644 index 0000000000..f2f70225ff --- /dev/null +++ b/test/typeparam/issue50841.dir/b.go @@ -0,0 +1,11 @@ +// 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 b + +import "a" + +func F() { + a.Marshal[int]() +} diff --git a/test/typeparam/issue50841.go b/test/typeparam/issue50841.go new file mode 100644 index 0000000000..060a1214cc --- /dev/null +++ b/test/typeparam/issue50841.go @@ -0,0 +1,7 @@ +// compiledir -G=3 + +// 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 ignored -- 2.50.0