cmd/vet: printf analyzer fails with generics

[larhun]

Go version

go version go1.22.3 windows/amd64

Output of go env in your module/workspace:

set GO111MODULE=
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\***\AppData\Local\go-build
set GOENV=C:\Users\***\AppData\Roaming\go\env
set GOEXE=.exe
set GOEXPERIMENT=
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GOMODCACHE=C:\Users\***\go\pkg\mod
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=C:\Users\***\go
set GOPRIVATE=
set GOPROXY=https://proxy.golang.org,direct
set GOROOT=C:\Program Files\Go
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLCHAIN=auto
set GOTOOLDIR=C:\Program Files\Go\pkg\tool\windows_amd64
set GOVCS=
set GOVERSION=go1.22.3
set GCCGO=gccgo
set GOAMD64=v1
set AR=ar
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=***
set GOWORK=
set CGO_CFLAGS=-O2 -g
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-O2 -g
set CGO_FFLAGS=-O2 -g
set CGO_LDFLAGS=-O2 -g
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=C:\Users\***\AppData\Local\Temp\go-build193180697=/tmp/go-build -gno-record-gcc-switches

What did you do?

Run this code in Go Playground (https://go.dev/play/p/Bop_vKP8EM0) or edit with vscode.

package main

import (
	"fmt"
)

type A struct{}

func (v A) Printf(format string, values ...any) {
	fmt.Printf(format, values...)
}

type B[T any] struct{}

func (v B[T]) Printf(format string, values ...any) {
	fmt.Printf(format, values...)
}

func main() {
	var a A
	var b B[bool]
	a.Printf("x", 1)
	b.Printf("x", 1)
}

What did you see happen?

Go vet failed on line 22 with the following log and line 22 is marked as failed in vscode.

# [play]
./prog.go:22:10: (play.A).Printf call has arguments but no formatting directives

Go vet failed.

x%!(EXTRA int=1)x%!(EXTRA int=1)
Program exited.

What did you expect to see?

Go vet failed on lines 22 and 23 with the following log and lines 22 and 23 are marked as failed in vscode.

# [play]
./prog.go:22:10: (play.A).Printf call has arguments but no formatting directives
./prog.go:23:10: (play.B).Printf call has arguments but no formatting directives

Go vet failed.

x%!(EXTRA int=1)x%!(EXTRA int=1)
Program exited.

[gabyhelp]

Related Issues

• cmd/vet: Printf format %.T has unrecognized flag #30363
• cmd/vet: printf analyzer cannot analyze anonymous functions #44350
• cmd/vet: doesn't handle formatting strings in variables #44063
• cmd/vet: false positive about wrong argument for verb #23552 (closed)
• go vet incorrectly recognizes format verb in string #38131 (closed)
• cmd/vet,x/tools/go/analysis/passes/printf: broken with GODEBUG=gotypesalias=1 #68796 (closed)
• cmd/vet: errors printed twice #26222 (closed)
• cmd/vet: report type and format specifier mismatch in Printf* #4404 (closed)
• cmd/vet: unexpected typecheck failures about "no field or method" #29883 (closed)
• cmd/vet: TestVet fails with the latest tip version #33481 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[GoVeronicaGo]

cc: @matloob

[adonovan]

Thanks for the helpful report; I agree that this is a bug.

[adonovan]

https://go.dev/cl/631955 fixes the bug in x/tools; but we would need to re-vendor or cherrypick it into GOROOT for cmd/vet in go1.24.

@dmitshur

[gopherbot]

Change https://go.dev/cl/631955 mentions this issue: go/analysis/passes/printf: add missing call to Func.Origin

[dmitshur]

@adonovan Ack. That'll happen before RC 1 via another round in #36905, or it can be an individual CL sooner.