Erroring in serverHTTP but not in my code, why?

First code: http://play.golang.org/p/OEDetydMbW

Second code: http://play.golang.org/p/QZIrWALAm_

Can somebody explain me why I am not getting error on First code, I was expecting to error out stating missing CreateTable method.

You specify an interface Abc with the method CreateTable but none of your variable are actually of type interface Abc
This slightly modified version will bring the error you seek:
http://play.golang.org/p/ETdexzPYaM

package main
import "log"
// Abc asdlkfjaslf as
type Abc interface {
	CreateTable(a, b)
}
type a int
type b int
// Def klajsdlfkjaslfd
type Def int
// // CreateTable laksjdfljasfdl
// func (d *Def) CreateTable() {
// 	log.Println("inside Def CreateTable....")
// }
func main() {
	var m1 Abc = Def(5)
	log.Println("inside main %d", m1)
}