유형 별칭으로 인해 Go의 유형 주장이 실패하는 이유는 무엇입니까?

package main

import "fmt"

type somethingFuncy func(int) bool

func funcy(i int) bool {
    return i%2 == 0
}

func main() {
    var a interface{} = funcy

    _ = a.(func(int) bool)  // Works

    fmt.Println("Awesome -- apparently, literally specifying the func signature works.")

    _ = a.(somethingFuncy)  // Panics

    fmt.Println("Darn -- doesn't get here. But somethingFuncy is the same signature as func(int) bool.")
}

func main() {
    var a interface{} = funcy

    switch v := a.(type) {
    case func(int) bool:
        // Type successfully asserted as func(int) bool
    case somethingFuncy:
        // Type successfully asserted as somethingFuncy
    default:
        // Type assertion failed
    }
}