Grandparent is correct. You didn't make an alias, because it's not interchangable:

http://play.golang.org/p/fiz0NnduNF

(try running it)

When I say "type MyInt int" didn't I just type-alias int?

No, you created a new type.

  cmccabe@keter:~/tmp> cat inta.go
  package main
  import "fmt"
  type myfoo int
  func printint(i int) {
    fmt.Printf("i = %d\n", i)
  }
  func main() {
    var foo myfoo
    printint(foo)
  }
  cmccabe@keter:~/tmp> go build inta.go 
  # command-line-arguments
  ./inta.go:13: cannot use foo (type myfoo) as type int in   argument to printint

You are probably thinking about "typedef" in C++, but go works differently in this case.

I would not consider your example to be one of a "type alias". Alias usually means that the names can be used interchangeably without a difference in behavior (i.e. casting). Go actually has some built-in aliases where this is the case. "byte" is an alias for "uint8". They can be used interchangeably. Here is an example of the distinction: http://play.golang.org/p/ukYCBqFeW_

It's not an alias, it's a new type. eg. http://play.golang.org/p/bXgryxNT0H