How to Use go vet: Syntax, Example, and Common Pitfalls

Use go vet by running it in your terminal inside your Go project directory to analyze your code for common mistakes and suspicious constructs. It checks your code without compiling it fully and reports issues to help you write better Go programs.

Syntax

The basic syntax of go vet is simple. You run it in your terminal followed by optional flags and the package or files you want to check.

• go vet [flags] [packages]
• flags modify the behavior (usually none needed for basic use)
• packages specify which Go packages or files to analyze (default is current directory)

Example: go vet ./... checks all packages in the current module recursively.

bash

go vet [flags] [packages]

# Example:
go vet ./...

Example

This example shows how go vet detects a suspicious printf call with mismatched arguments.

go

package main

import "fmt"

func main() {
    name := "Alice"
    age := 30
    // Incorrect: missing argument for age
    fmt.Printf("Name: %s, Age: %d\n", name)
}

Output

# command-line-arguments
./main.go:9:39: Printf format %d has arg missing

Common Pitfalls

Common mistakes when using go vet include:

• Ignoring its output, which can catch subtle bugs early.
• Running it outside your project directory, so it finds no files.
• Confusing go vet with go build or go test; go vet only checks code correctness, not compilation or tests.

Always fix reported issues to improve code quality.

go

package main

import "fmt"

func main() {
    var x int
    // Wrong: unused variable x triggers vet warning
    fmt.Println("Hello")
}

Output

# command-line-arguments
./main.go:6:6: x declared and not used

Quick Reference

Command	Description
go vet	Run vet on current package
go vet ./...	Run vet on all packages recursively
go vet -all	Enable all checks (default)
go vet -printfuncs=func1,func2	Add custom printf-like functions to check
go vet -shadow	Detect variable shadowing issues

Key Takeaways

Run go vet in your project directory to find common Go code mistakes.

go vet helps catch bugs like format string errors and unused variables before compiling.

Use go vet ./... to check all packages recursively.

Pay attention to go vet warnings and fix them to improve code quality.

Remember go vet checks code correctness, not compilation or tests.