在golang的If-else块中为变量分配不同的结构

I want to do something like this

type Struct1 {
    a string
}
type Struct 2{
    b int
}

if something{
    c := Struct1{a:''}
}else{
    c := Struct2{b:1}
}

somefunc(c)

I know I can't declare c inside of one block and then access it outside.

I tried something like this

type Struct1 {
    a string
}
type Struct 2{
    b int
}

c := Struct2{b:1}
if something{
    c := Struct1{a:''}
}

somefunc(c)

It gives error- Cannot assign Struct1 to c(type Struct2)

How can I achieve something like this?

You can, use an interface{}

package main

import (
    "fmt"
)

type Struct1 struct {
    a string
}

type Struct2 struct {
    b int
}

func main() {
    var c interface{}
    if true {
        c = Struct1{a: ""}
    } else {
        c = Struct2{b: 1}
    }
    fmt.Printf("type %T", c)
}
// Print:
// type main.Struct1

https://play.golang.org/p/Z1cT9qjFmfU