Why is struct creation in an if statement illegal in Go?

go

Solution

You have to surround the right side of the == with parenthesis. Otherwise go will think that the '{' is the beginning of the 'if' block. The following code works fine:

package main

import "fmt"

type Auth struct {
    Username    string
    Password    string
}

func main() {
    auth := Auth { Username : "abc", Password : "123" }
    if auth == (Auth {Username: "abc", Password: "123"}) {
        fmt.Println(auth)
    }
}

// Output: {abc 123}

Problem

Go complains about instantiating a struct in an if-statement. Why? Is there correct syntax for this that doesn't involve temporary variables or new functions? ``` type Auth struct { Username string Password string } func main() { auth := Auth { Username : "abc", Password : "123" } if auth == Auth {Username: "abc", Password: "123"} { fmt.Println(auth) } } ``` Error (on the if-statement line): syntax error: unexpected :, expecting := or = or comma This yields the same error: ``` if auth2 := Auth {Username: "abc", Password: "123"}; auth == auth2 { fmt.Println(auth) } ``` This works as expected: ``` auth2 := Auth {Username: "abc", Password: "123"}; if auth == auth2 { fmt.Println(auth) } ```

Original source