golang/go
fmt: state that "%q" verb should not be used to print int value
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#78,486 opened on Apr 1, 2026
DocumentationNeedsFixhelp wanted
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Description
Go version
go version go1.26.1 darwin/arm64
Output of go env in your module/workspace:
AR='ar'
CC='clang'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='0'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='clang++'
GCCGO='gccgo'
GO111MODULE=''
GOARCH='arm64'
GOARM64='v8.0'
GOAUTH='netrc'
GOBIN='…'
GOCACHE='…'
GOCACHEPROG=''
GODEBUG=''
GOENV='…'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -arch arm64 -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/sl/yg232rm16b74lh69dhhscfz40000gn/T/go-build3024692398=/tmp/go-build -gno-record-gcc-switches -fno-common'
GOHOSTARCH='arm64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMOD='…'
GOMODCACHE='…'
GONOPROXY='…'
GONOSUMDB='…'
GOOS='darwin'
GOPATH='…'
GOPRIVATE='…'
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/nix/store/kh43nhaz1qcpwws2xq805lrmwpmn9i3k-go-1.26.1/share/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='off'
GOTELEMETRYDIR='…'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/nix/store/kh43nhaz1qcpwws2xq805lrmwpmn9i3k-go-1.26.1/share/go/pkg/tool/darwin_arm64'
GOVCS=''
GOVERSION='go1.26.1'
GOWORK=''
PKG_CONFIG='pkg-config'
What did you do?
package main
import "fmt"
func main() {
var i int = 42
fmt.Printf("%q\n", i)
}
https://go.dev/play/p/19ECZqyEHs_A
What did you see happen?
prog.go:7:14: fmt.Printf format %q has arg i of wrong type int
Go vet failed.
'*'
Program exited.
What did you expect to see?
The fmt docs state that the %q verb can be used to print integers:
%q a single-quoted character literal safely escaped with Go syntax.:
https://pkg.go.dev/fmt#:~:text=Integer%3A
As of Go 1.26, this however no longer passes go vet:
$ go vet prog.go
prog.go:7:14: fmt.Printf format %q has arg i of wrong type int
The docs on fmt should reflect that.
That vet error was introduced as part of https://github.com/golang/go/issues/72850.