What version of Go are you using (go version)?
$ go version
go version go1.18beta1 linux/amd64
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
GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/bobg/.cache/go-build"
GOENV="/home/bobg/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/bobg/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/bobg/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/bobg/sdk/go1.18beta1"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/bobg/sdk/go1.18beta1/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.18beta1"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/bobg/go/src/github.com/bobg/modver/go.mod"
GOWORK=""
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-build3923542930=/tmp/go-build -gno-record-gcc-switches"
What did you do?
https://go.dev/play/p/S-ijx-XOlu8?v=gotip
var (
anyType = types.Universe.Lookup("any").Type()
comparableType = types.Universe.Lookup("comparable").Type()
)
fmt.Println(types.AssignableTo(comparableType, anyType))
fmt.Println(types.AssignableTo(anyType, comparableType))What did you expect to see?
true
false
That is, I (naively?) expected the same check that prevents me using non-comparable types as map keys to tell me that I cannot assign a value of an unconstrained type to a variable of a comparable type.
What did you see instead?
true
true
What version of Go are you using (
go version)?Does this issue reproduce with the latest release?
Yes
What operating system and processor architecture are you using (
go env)?go envOutputWhat did you do?
https://go.dev/play/p/S-ijx-XOlu8?v=gotip
What did you expect to see?
true
false
That is, I (naively?) expected the same check that prevents me using non-comparable types as map keys to tell me that I cannot assign a value of an unconstrained type to a variable of a comparable type.
What did you see instead?
true
true