Arnaud, GODEBUG=gotypesalias=1 was not redundant in my command. It was used to suppress go vet error checking.
peter On Sunday, August 25, 2024 at 5:30:25 PM UTC-4 Arnaud Delobelle wrote: > Hi Peter, > > Thanks for mentioning gotypesalias. Looking into that, I see that the > go1.23 release notes mention that: > > By default, go/types now produces Alias type nodes for type aliases. > This behavior can be controlled by the GODEBUG gotypesalias flag. Its > default has changed from 0 in Go 1.22 to 1 in Go 1.23. > > This is supported by the test below. By default go vet does not flag the > error, but it does if GODEBUG=gotypesalias=0 (so GODEBUG=gotypesalias=1 was > redundant in your command) > > ❯ go version > go version go1.23.0 darwin/arm64 > echo $GODEBUG > > ❯ go vet sample.go > ❯ GODEBUG=gotypesalias=0 go vet sample.go > # command-line-arguments > # [command-line-arguments] > vet: ./sample.go:15:4: invalid use of type alias B in recursive type (see > go.dev/issue/50729) > > However on the Go playground go vet reports the error ( > https://go.dev/play/p/fjy9259UHPY). Does this mean that the Go > playground is configured with GODEBUG=gotypesalias=0? Is that not an issue > with the Go playground? I think the Go playground should give output > consistent with a local installation. > > Also it seems that gopls flags this error too by default, even though go > vet no longer does. This also appears to me to be an issue, though a lot > harder to diagnose because I can only observe the outcome via the black box > of vscode (or another editor configured with gopls). I do not know how to > run gopls as a standalone tool on a file (I do not even know if such a > thing is possible). > > -- > Arnaud > > On Sun, 25 Aug 2024 at 18:10, peterGo <go.pe...@gmail.com> wrote: > >> Arnaud, >> >> $ go version && go run alias.go && go vet alias.go >> go version devel go1.24-96d8ff00c2 Sat Aug 24 00:51:40 2024 +0000 >> linux/amd64 >> b = {X:0xc00011c190 Y:0xc00011c1a0} >> $ >> >> Or >> >> $ go1.23 version && go1.23 run alias.go && GODEBUG=gotypesalias=1 go1.23 >> vet alias.go >> go version go1.23.0 linux/amd64 >> b = {X:0xc0000141c0 Y:0xc0000141d0} >> $ >> >> peter >> >> On Saturday, August 24, 2024 at 5:37:20 PM UTC-4 Arnaud Delobelle wrote: >> >>> Hi all >>> >>> I ran into this error with generic types. Here is the sample program >>> below, which is my best effort to boil it down to its simplest expression. >>> >>> I can build and run the program fine with go 1.23.0. However, on line >>> 15 vscode reports the error I put in the comment on that line. I do not >>> know how to determine what tool is instructing vscode to report this error >>> (I imagine it's gopls but I have no proof). >>> >>> package main >>> >>> import "fmt" >>> >>> func main() { >>> b := B{X: &A1{X: B{}}, Y: &A2{X: B{}}} >>> fmt.Printf("b = %#v", b) >>> } >>> >>> type A1 struct { >>> X B >>> } >>> >>> type A2 struct { >>> X B // invalid use of type alias B in recursive type (see >>> go.dev/issue/50729)compilerInvalidDeclCycle >>> } >>> >>> type G[T1, T2 any] struct { >>> X *T1 >>> Y *T2 >>> } >>> >>> type B = G[A1, A2] >>> >>> >>> Here is the same program in the go playground: >>> https://go.dev/play/p/fjy9259UHPY. If I click "Run" I get this output: >>> >>> # [play] >>> vet: ./prog.go:15:4: invalid use of type alias B in recursive type (see >>> go.dev/issue/50729) >>> Go vet failed. >>> b = {X:0xc00009e050 Y:0xc00009e060} >>> Program exited. >>> >>> >>> So "go vet" fails, but the program builds and runs OK. However, if I >>> run "go vet" on my machine, no errors are reported! >>> >>> Can someone explain what is happening? To sum up >>> - the program builds and runs even though an error is reported in vscode >>> and the same error by go vet on the Go playground >>> - go vet reports an error in the Go playground, but not on my machine >>> (they both reportedly run go 1.23.0) >>> - possibly gopls reports this error too? I do not know if it is the >>> tool that tells vscode of the error on my machine (I run gopls 0.16.1) >>> >>> What I'd like to know: >>> - if someone can tell me how to determine what tool is telling vscode to >>> report this error, it would help me find where to report this issue >>> - if someone could confirm whether the program is indeed supposed to be >>> correct, it would also help me (I suspect it should be correct, as it >>> builds and runs successfully) >>> >>> Thanks in advance >>> >>> -- >>> Arnaud >>> >>> PS: Apologies for the html-formatted email, but I couldn't figure out >>> how to paste code into gmail without losing all the indentation >>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "golang-nuts" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to golang-nuts...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/golang-nuts/3084309c-bac4-4851-ab1f-364568b4400cn%40googlegroups.com >> >> <https://groups.google.com/d/msgid/golang-nuts/3084309c-bac4-4851-ab1f-364568b4400cn%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/ef0fd15b-27ed-433f-a519-122ff3e84974n%40googlegroups.com.
