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gccgo/gollvm: incorrect finalization of ambiguous promoted methods #52870

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AblakatovMikhail opened this issue May 12, 2022 · 3 comments
Closed

gccgo/gollvm: incorrect finalization of ambiguous promoted methods #52870

AblakatovMikhail opened this issue May 12, 2022 · 3 comments
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FrozenDueToAge NeedsFix The path to resolution is known, but the work has not been done.
Milestone
Gccgo

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@AblakatovMikhail
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If a type that is stored directly in an interface data word includes ambiguous promoted methods, finalization of its methods results in error: incompatible type for receiver (cannot use type <A> as type <B>).

What version of Go are you using (go version)?

$ go version
go version unknown linux/amd64
llvm-project/llvm/tools/gollvm$ git log --oneline | head -n 1
0e34e09 gollvm: add /usr/{lib,lib32} to toolchain paths for arch linux
llvm-project/llvm/tools/gollvm/gofrontend$ git log --oneline | head -n 1
6a33e7e3 compiler: remove Array_index_expression::is_lvalue_

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output
$ go env

What did you do?

The issue may be reproduced with the following sample:

foo/foo.go

package foo

import "bar"

type Foo struct {
        *bar.Bar
}

func (f *Foo) Personal(a int) error {
        return nil
}

bar/bar.go

package bar

import "baz"

type Bar struct {
        baz.Baz1
        baz.Baz2
}

baz/baz1.go

package baz

type Baz1 int32

func (b Baz1) Promoted() int {
        return 1
}

baz/baz2.go

package baz

type Baz2 int32

func (b Baz2) Promoted() int {
        return 2
}

What did you expect to see?

No error, successful build.

What did you see instead?

An attempt to build this sample results in:

$ GO111MODULE=off go build foo
# foo
foo/foo.go:5:6: error: incompatible type for receiver (cannot use type Foo as type baz.Baz1)
@gopherbot gopherbot added this to the Gccgo milestone May 12, 2022
@AblakatovMikhail
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I'll submit a fix for this issue soon.

cc @ianlancetaylor

@gopherbot
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Change https://go.dev/cl/405974 mentions this issue: compiler: don't generate stubs for ambiguous direct interface methods

@heschi heschi added the NeedsFix The path to resolution is known, but the work has not been done. label May 13, 2022
@gopherbot
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Change https://go.dev/cl/412535 mentions this issue: test: add test that gofrontend fails

gopherbot pushed a commit that referenced this issue Jun 16, 2022
@ianlancetaylor @gopherbot
test: add test that gofrontend fails
ecc268a 
For #52870

Change-Id: Ic0791af4283c9e426f7cbfab0514517ff84cfa80
Reviewed-on: https://go-review.googlesource.com/c/go/+/412535
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
xionghul pushed a commit to xionghul/gcc that referenced this issue Jun 16, 2022
@ianlancetaylor
compiler: don't generate stubs for ambiguous direct interface methods
b2aaa44 
Current implementation checks whether it has to generate a stub method for a
promoted method of an embedded struct field in Type::build_stub_methods(). If
the promoted method is ambiguous it's simply skipped. But struct types that
can fit in an interface value (e.g. structs that consist of a single pointer
field) get a second chance in Type::build_direct_iface_stub_methods().

This patch adds the same check used by Type::build_stub_methods() to
Type::build_direct_iface_stub_methods().

Fixes golang/go#52870

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/405974
realqhc pushed a commit to realqhc/gofrontend that referenced this issue Aug 4, 2022
@realqhc
compiler: don't generate stubs for ambiguous direct interface methods
5411f36 
Current implementation checks whether it has to generate a stub method for a
promoted method of an embedded struct field in Type::build_stub_methods(). If
the promoted method is ambiguous it's simply skipped. But struct types that
can fit in an interface value (e.g. structs that consist of a single pointer
field) get a second chance in Type::build_direct_iface_stub_methods().

This patch adds the same check used by Type::build_stub_methods() to
Type::build_direct_iface_stub_methods().

Fixes golang/go#52870

Change-Id: If679e7bda8793b3cdc411419806fa36d5536faa4
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/405974
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
@golang golang locked and limited conversation to collaborators Jun 16, 2023
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@gopherbot @heschi @AblakatovMikhail