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go/types: type-check embedded methods in wrong scope #25008

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nabice opened this issue Apr 23, 2018 · 7 comments
Closed

go/types: type-check embedded methods in wrong scope #25008

nabice opened this issue Apr 23, 2018 · 7 comments

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@nabice
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@nabice nabice commented Apr 23, 2018

Please answer these questions before submitting your issue. Thanks!

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

go version devel +d11df8baa8 Sun Apr 22 22:32:11 2018 +0000 linux/amd64

Does this issue reproduce with the latest release?

no, only recent commit d11df8b

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

GOARCH="amd64"
GOBIN=""
GOCACHE="/home/nabice/.cache/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/nabice/go:/home/nabice/skygo/go"
GORACE=""
GOROOT="/home/nabice/source/go"
GOTMPDIR=""
GOTOOLDIR="/home/nabice/source/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build162693936=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Two go files:
a.go

package main

import (
        "fmt"
        "io"
)

type A interface {
        io.Reader
}

type A1 struct {
}

func (d *A1) Read(p []byte) (n int, err error) {
        fmt.Println("A1")
        return 0, nil
}

func bbb(t A) {
        t.Read(nil)
}

func main() {
        a := new(A1)
        bbb(a)
}

b.go

package main

type B interface {
    A
}

go vet a.go b.go runs OK
go vet b.go a.go failed.

The reason is that, in file src/go/types/interfaces.go:226, We pass wrong context(scope) to lookup for "io". So typecheck cannot found io.Reader.

stack trace:

 0  0x000000000062ab05 in go/types.(*Checker).infoFromTypeLit
    at ./interfaces.go:226
 1  0x000000000062b45a in go/types.(*Checker).infoFromTypeName
    at ./interfaces.go:339
 2  0x000000000062a91a in go/types.(*Checker).infoFromTypeLit
    at ./interfaces.go:224
 3  0x0000000000658272 in go/types.(*Checker).interfaceType
    at ./typexpr.go:545

When we check b.go firstly, go tries to get A's info from b.go's scope

What did you expect to see?

No error found

What did you see instead?

# command-line-arguments

./a.go:21:4: invalid operation: t (variable of type A) has no field or method Read
vet: typecheck failures
@FiloSottile FiloSottile changed the title type-check embedded methods in wrong scope go/types: type-check embedded methods in wrong scope Apr 24, 2018
@FiloSottile FiloSottile added this to the Go1.11 milestone Apr 24, 2018
@FiloSottile
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@FiloSottile FiloSottile commented Apr 24, 2018

/cc @griesemer

Looks similar to #23914 and #24140

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@griesemer griesemer self-assigned this Apr 24, 2018
@griesemer
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@griesemer griesemer commented Apr 24, 2018

@nabice Thanks for this report and the (correct) analysis! Fix forthcoming.

A shorter reproducer:

  • a.go
package p

import "io"

type A interface {
        io.Reader
}

func f(a A) {
        a.Read(nil)
}
  • b.go
package p

type B interface {
    A
}

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@gopherbot
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@gopherbot gopherbot commented Apr 24, 2018

Change https://golang.org/cl/109139 mentions this issue: go/types: use correct (file) scopes when computing interface method sets

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@gopherbot gopherbot closed this in 73becbf Apr 25, 2018
@myitcv
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@myitcv myitcv commented Apr 27, 2018

@griesemer we just had another instance of this via gopherjs/gopherjs#808 - would you consider back-porting this fix to the 1.10 series?

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@myitcv
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@myitcv myitcv commented Apr 27, 2018

Edit: fixed typo below in second paragraph.

Just to add a bit more colour.

Using 1.10.1, type checking gorgonia.org/gorgonia with go/types succeeds when using importer.For("gc", nil), but fails with importer.For("source", nil).

Using tip it succeeds in both cases (the fix was introduced by https://go-review.googlesource.com/c/go/+/109139).

Here are the repro steps I used:

cd `mktemp -d`
export GOPATH=$PWD
go get gorgonia.org/gorgonia
go install $(go list -f '{{join .Deps " "}}' gorgonia.org/gorgonia )
cat <<EOD > check.go
// +build ignore

package main

import (
	"fmt"
	"go/ast"
	"go/build"
	"go/importer"
	"go/parser"
	"go/token"
	"go/types"
	"os"
	"path/filepath"
)

func main() {
	bpkg, err := build.Import("gorgonia.org/gorgonia", ".", 0)
	if err != nil {
		fatalf("failed to import .: %v", err)
	}

	fset := token.NewFileSet()
	var files []*ast.File

	for _, f := range bpkg.GoFiles {
		fp := filepath.Join(bpkg.Dir, f)
		fi, err := os.Open(fp)
		if err != nil {
			fatalf("failed to open %v: %v", fp, err)
		}

		pf, err := parser.ParseFile(fset, fp, fi, 0)
		if err != nil {
			fatalf("failed to parse %v: %v", fp, err)
		}

		files = append(files, pf)
	}

	{
		conf := types.Config{
			Importer: importer.For("gc", nil),
		}

		_, err = conf.Check("gorgonia.org/gorgonia", fset, files, nil)
		if err != nil {
			fatalf("type checking failed using gc importer: %v", err)
		}
	}

	{
		conf := types.Config{
			Importer: importer.For("source", nil),
		}

		_, err = conf.Check("gorgonia.org/gorgonia", fset, files, nil)
		if err != nil {
			fatalf("type checking failed using source importer: %v", err)
		}
	}
}

func fatalf(format string, args ...interface{}) {
	fmt.Fprintf(os.Stderr, format+"\n", args...)
	os.Exit(1)
}
EOD
go run check.go 

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@griesemer
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@griesemer griesemer commented Apr 30, 2018

@myitcv While the CL https://go-review.googlesource.com/c/go/+/109139 fixed this specific issue, the fix is in a (significant) chunk of code that doesn't even exist in the 1.10 version of go/types (https://tip.golang.org/src/go/types/interfaces.go was added, and https://golang.org/src/go/types/ordering.go was removed). So back-porting this fix implies a much larger change than what meets the eye.

You may be able to (temporarily) work around the problem by re-arranging some your source code (relative order of method and interface declarations). It doesn't always work but it's worth a try.

Is there a reason not to move to 1.11 in gorgonia, or perhaps (for now) vendor the latest version of go/types?

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@myitcv
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@myitcv myitcv commented May 1, 2018

the fix is in a (significant) chunk of code that doesn't even exist in the 1.10 version of go/types

Ah, I hadn't realised this. Thank you for clarifying.

... or perhaps (for now) vendor the latest version of go/types?

Excellent suggestion, thank you. We can do that within GopherJS (which is ultimately where we get bitten by this) until we release GopherJS 1.11 that corresponds to Go 1.11.

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myitcv added a commit to myitcv/gopherjs that referenced this issue May 1, 2018
Per golang/go#25008 (comment) the
fix for method set calculation will not be back ported to Go 1.10.
Instead gri suggests we vendor the latest version of go/types. This PR
does just that. It is effectively a temporary sticking plaster until Go
1.11 lands, or more specifically until we release GopherJS for Go 1.11.

In order to successfully vendor go/types, however, we need to move
compiler/vendor to the repo root (because build also uses go/types). And
because golang.org/x/tools/go/gcexportdata and
golang.org/x/tools/go/types/typeutil also reference go/types we need to
vendor them as well.

vendor/vendor.json is updated using govendor, with the one exception
being a manual addition for go/types (govendor doesn't appear to
understand how to vendor a standard library package).

Fixes gopherjs#808.
myitcv added a commit to myitcv/gopherjs that referenced this issue Jul 2, 2018
Per golang/go#25008 (comment) the
fix for method set calculation will not be back ported to Go 1.10.
Instead gri suggests we vendor the latest version of go/types. This PR
does just that. It is effectively a temporary sticking plaster until Go
1.11 lands, or more specifically until we release GopherJS for Go 1.11.

In order to successfully vendor go/types, however, we need to move
compiler/vendor to the repo root (because build also uses go/types). And
because golang.org/x/tools/go/gcexportdata and
golang.org/x/tools/go/types/typeutil also reference go/types we need to
vendor them as well.

vendor/vendor.json is updated using govendor, with the one exception
being a manual addition for go/types (govendor doesn't appear to
understand how to vendor a standard library package).

Fixes gopherjs#808.
myitcv added a commit to myitcv/gopherjs that referenced this issue Jul 2, 2018
Per golang/go#25008 (comment) the
fix for method set calculation will not be back ported to Go 1.10.
Instead gri suggests we vendor the latest version of go/types. This PR
does just that. It is effectively a temporary sticking plaster until Go
1.11 lands, or more specifically until we release GopherJS for Go 1.11.

In order to successfully vendor go/types, however, we need to move
compiler/vendor to the repo root (because build also uses go/types). And
because golang.org/x/tools/go/gcexportdata and
golang.org/x/tools/go/types/typeutil also reference go/types we need to
vendor them as well.

vendor/vendor.json is updated using govendor, with the one exception
being a manual addition for go/types (govendor doesn't appear to
understand how to vendor a standard library package).

Fixes gopherjs#808.
myitcv added a commit to myitcv/gopherjs that referenced this issue Jul 2, 2018
Per golang/go#25008 (comment) the
fix for method set calculation will not be back ported to Go 1.10.
Instead gri suggests we vendor the latest version of go/types. This PR
does just that. It is effectively a temporary sticking plaster until Go
1.11 lands, or more specifically until we release GopherJS for Go 1.11.

In order to successfully vendor go/types, however, we need to move
compiler/vendor to the repo root (because build also uses go/types). And
because golang.org/x/tools/go/gcexportdata and
golang.org/x/tools/go/types/typeutil also reference go/types we need to
vendor them as well.

vendor/vendor.json is updated using govendor, with the one exception
being a manual addition for go/types (govendor doesn't appear to
understand how to vendor a standard library package).

Fixes gopherjs#808.
myitcv added a commit to myitcv/gopherjs that referenced this issue Jul 2, 2018
Per golang/go#25008 (comment) the
fix for method set calculation will not be back ported to Go 1.10.
Instead gri suggests we vendor the latest version of go/types. This PR
does just that. It is effectively a temporary sticking plaster until Go
1.11 lands, or more specifically until we release GopherJS for Go 1.11.

In order to successfully vendor go/types, however, we need to move
compiler/vendor to the repo root (because build also uses go/types). And
because golang.org/x/tools/go/gcexportdata and
golang.org/x/tools/go/types/typeutil also reference go/types we need to
vendor them as well.

vendor/vendor.json is updated using govendor, with the one exception
being a manual addition for go/types (govendor doesn't appear to
understand how to vendor a standard library package).

Fixes gopherjs#808.
@golang golang locked and limited conversation to collaborators May 1, 2019
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