Syntax error with generics

[lcarva]

What did you do? (required: The issue will be closed when not provided)

Edited this go file:

package main

func test[T any](s []T) {
}

func main() {
}

What did you expect to happen?

I expected no errors since this is valid syntax.

What happened instead?

The following error is displayed on save:

main.go|3 col 10| expected '(', found '['

Configuration (MUST fill this out):

vim-go version:

v1.26

vimrc you used to reproduce:

The bare minimum:

$ cat ~/.vimrc
execute pathogen#infect()

vim-go is the only plugin installed.

Vim version (first three lines from :version):

vim --version Output:

VIM - Vi IMproved 9.0 (2022 Jun 28, compiled Dec 05 2022 00:00:00)

Included patches: 1-1006

Modified by [email protected]

Compiled by [email protected]

Huge version without GUI.  Features included (+) or not (-):

+acl               +file_in_path      +mouse_urxvt       -tag_any_white

+arabic            +find_in_path      +mouse_xterm       -tcl

+autocmd           +float             +multi_byte        +termguicolors

+autochdir         +folding           +multi_lang        +terminal

-autoservername    -footer            -mzscheme          +terminfo

-balloon_eval      +fork()            +netbeans_intg     +termresponse

+balloon_eval_term +gettext           +num64             +textobjects

-browse            -hangul_input      +packages          +textprop

++builtin_terms    +iconv             +path_extra        +timers

+byte_offset       +insert_expand     +perl/dyn          +title

+channel           +ipv6              +persistent_undo   -toolbar

+cindent           +job               +popupwin          +user_commands

-clientserver      +jumplist          +postscript        +vartabs

-clipboard         +keymap            +printer           +vertsplit

+cmdline_compl     +lambda            +profile           +vim9script

+cmdline_hist      +langmap           -python            +viminfo

+cmdline_info      +libcall           +python3/dyn       +virtualedit

+comments          +linebreak         +quickfix          +visual

+conceal           +lispindent        +reltime           +visualextra

+cryptv            +listcmds          +rightleft         +vreplace

+cscope            +localmap          +ruby/dyn          +wildignore

+cursorbind        +lua/dyn           +scrollbind        +wildmenu

+cursorshape       +menu              +signs             +windows

+dialog_con        +mksession         +smartindent       +writebackup

+diff              +modify_fname      +sodium            -X11

+digraphs          +mouse             -sound             -xfontset

-dnd               -mouseshape        +spell             -xim

-ebcdic            +mouse_dec         +startuptime       -xpm

+emacs_tags        +mouse_gpm         +statusline        -xsmp

+eval              -mouse_jsbterm     -sun_workshop      -xterm_clipboard

+ex_extra          +mouse_netterm     +syntax            -xterm_save

+extra_search      +mouse_sgr         +tag_binary

-farsi             -mouse_sysmouse    -tag_old_static

system vimrc file: "/etc/vimrc"

user vimrc file: "$HOME/.vimrc"

2nd user vimrc file: "~/.vim/vimrc"

user exrc file: "$HOME/.exrc"

defaults file: "$VIMRUNTIME/defaults.vim"

fall-back for $VIM: "/usr/share/vim"

Compilation: gcc -c -I. -Iproto -DHAVE_CONFIG_H -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -DSYS_VIMRC_FILE=/etc/vimrc -D_REENTRANT -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1

Linking: gcc -Wl,--enable-new-dtags -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -Wl,--build-id=sha1 -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -Wl,--build-id=sha1 -Wl,-dT,/builddir/build/BUILD/vim90/.package_note-vim-9.0.1006-1.fc36.x86_64.ld -L/usr/local/lib -o vim -lm -lselinux -lncurses -lsodium -lacl -lattr -lgpm -Wl,--enable-new-dtags -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -Wl,--build-id=sha1 -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -Wl,--build-id=sha1 -fstack-protector-strong -L/usr/local/lib -L/usr/lib64/perl5/CORE -lperl -lpthread -lresolv -ldl -lm -lcrypt -lutil -lc

Go version (go version):

go version go1.18.8 linux/amd64

Go environment

go env Output:

GO111MODULE=""

GOARCH="amd64"

GOBIN=""

GOCACHE="/home/lucarval/.cache/go-build"

GOENV="/home/lucarval/.config/go/env"

GOEXE=""

GOEXPERIMENT=""

GOFLAGS=""

GOHOSTARCH="amd64"

GOHOSTOS="linux"

GOINSECURE=""

GOMODCACHE="/home/lucarval/gocode/pkg/mod"

GONOPROXY=""

GONOSUMDB=""

GOOS="linux"

GOPATH="/home/lucarval/gocode"

GOPRIVATE=""

GOPROXY="https://proxy.golang.org,direct"

GOROOT="/usr/lib/golang"

GOSUMDB="off"

GOTMPDIR=""

GOTOOLDIR="/usr/lib/golang/pkg/tool/linux_amd64"

GOVCS=""

GOVERSION="go1.18.8"

GCCGO="gccgo"

GOAMD64="v1"

AR="ar"

CC="gcc"

CXX="g++"

CGO_ENABLED="1"

GOMOD="/tmp/test/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-build2404005566=/tmp/go-build -gno-record-gcc-switches"

gopls version

gopls version Output:

golang.org/x/tools/gopls v0.7.5
    golang.org/x/tools/[email protected] h1:8Az52YwcFXTWPvrRomns1C0N+zlgTyyPKWvRazO9GG8=

[lcarva]

Similar to #3398 but in my case I have no other plugin installed, so it's coming from vim-go.

[bhcleek]

What does :!go version output?

[bhcleek]

Oh, you're running a very old version of gopls, so I suspect that it's not been compiled with a recent version of Go that supports generics. Try :GoUpdateBinaries gopls. Can you duplicate the problem after updating gopls?

[gucio321]

Hi!
I'm getting the same error. GoUpdateBinaries gopls doesn't help.
gopls version is

[bin (2) ]$ gopls version
golang.org/x/tools/gopls v0.10.1
    golang.org/x/tools/[email protected] h1:JoHe17pdZ8Vsa24/GUO8iTVTKPh0EOBiWpPop7XJybI=

go version: go version go1.19.3 linux/amd64

[lcarva]

I think there's something up with my setup. When I run :GoUpdateBinaries gopls, I get a bunch of errors like this:

vim-go: Error installing golang.org/x/tools/gopls@latest: golang.org/x/exp/constraints
vim-go: golang.org/x/exp/maps
vim-go: # golang.org/x/exp/constraints
vim-go: /home/lucarval/gocode/pkg/mod/golang.org/x/[email protected]/constraints/constraints.go:13:2: emb
edding interface element ~int|~int8|~int16|~int32|~int64 requires go1.18 or later (-lang was set to go1.16; check go.mod)
vim-go: /home/lucarval/gocode/pkg/mod/golang.org/x/[email protected]/constraints/constraints.go:20:2: emb
edding interface element ~uint|~uint8|~uint16|~uint32|~uint64|~uintptr requires go1.18 or later (-lang was set to go1.16; chec
k go.mod)
vim-go: /home/lucarval/gocode/pkg/mod/golang.org/x/[email protected]/constraints/constraints.go:27:2: emb
edding interface element Signed|Unsigned requires go1.18 or later (-lang was set to go1.16; check go.mod)

But the output of :!go version is:

go version go1.18.8 linux/amd64

Is it possible that vim-go is using a different golang binary? Not sure how to check this.

[lcarva]

Ok, the :GoUpdateBinaries command still fails. However, I was able to get around this by running:

$ go install golang.org/x/tools/gopls@latest

which now shows:

$ gopls version
golang.org/x/tools/gopls v0.10.1
    golang.org/x/tools/[email protected] h1:JoHe17pdZ8Vsa24/GUO8iTVTKPh0EOBiWpPop7XJybI=

[lcarva]

I narrowed down the problem to the use of -mod=readonly. I can reproduce the error I see when running :GoUpdateBinaries like this:

go install -v -mod=readonly golang.org/x/tools/gopls@latest

Removing -mod=readonly fixes the issue. I noticed that #3449 changes this to -mod=mod which also fixes the issue.

So I'm all set here if I use the master branch.

To summarize, the initial issue I reported was due to an outdated gopls version being used. Running :GoUpdateBinaries fixes it. However, :GoUpdateBinaries seems to be broken in version 1.26 but already fixed in master.