go/types: tip: math/all_test.go:1963:2: constant overflow

[dominikh]

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

$ go version
go version devel go1.17-9c7207891c Fri Apr 30 05:18:37 2021 +0000 linux/amd64

Does this issue reproduce with the latest release?

No.

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

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/dominikh/.cache/go-build"
GOENV="/home/dominikh/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/dominikh/prj/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/dominikh/prj"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/dominikh/prj/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/dominikh/prj/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="devel go1.17-9c7207891c Fri Apr 30 05:18:37 2021 +0000"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/dominikh/prj/src/sandbox/baz/go.mod"
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-build3029975122=/tmp/go-build -gno-record-gcc-switches"

What did you do?

https://play.golang.org/p/9NB6JwDlteB

The issue does not reproduce with Go 1.16.2. I cannot reproduce it with go vet or gotype.go, either, unfortunately. This might be a misuse of the go/types API in Staticcheck, but I couldn't find any mistakes yet.

git bisect points at 168d6a4 (/cc @findleyr)

What did you expect to see?

math []
math [math.test] []
math_test [math.test] []
math.test []

What did you see instead?

math []
math [math.test] []
math_test [math.test] [/home/dominikh/prj/go/src/math/all_test.go:1963:2: constant  overflow]
math.test []

[cuonglm]

I think the problem is #45837

Your "honnef.co/go/tools/go/loader" use gcimporter, which currently has the same restriction with gc.

[findleyr]

Thanks for reporting, and for the repro. @cuonglm may be right -- I'll take a look.

[findleyr]

The problem is that gcimporter is not preserving the constant Kind. We've seen this before: this was fixed in x/tools in https://golang.org/cl/307590, but that fix did not make it in to honnef.co/go/tools.

@dominikh, what is your process for keeping in-sync with x/tools? Is this liable to bite users of staticcheck who may upgrade Go, but not staticcheck?

[findleyr]

Is this liable to bite users of staticcheck who may upgrade Go, but not staticcheck?

To clarify: is it common for users to install older versions of staticcheck, or do you see any other reasons why this problem is not fixable?

[dominikh]

is it common for users to install older versions of staticcheck

I don't believe so, and officially a Staticcheck release supports the last two releases of Go, and makes no promises about forward compatibility. Pulling in the changes and making a new release should fix the issue.

Presumably this issue can be closed, then?

I'm sorry for making you debug an issue that was ultimately in "my" code.

[findleyr]

No problem at all. This overflow check was a change in behavior in go/types (arguably a bug fix), and I wanted to understand its ramifications.

Yes, I think this can be closed now.