instantiate by reflection - go

Question

Given a function with a parameter (that is a pointer to a struct) I want to instantiate a type of this parameter.
For example, for this function:
func MyFunction(myStruct *MyStruct) {}
using reflection I want to create a variable that contains exactly same as x := &MyStruct{} would contain.
This is the code example:
package main
import (
"fmt"
"reflect"
)
type MyStruct struct {
}
func main () {
reflectedFunction := reflect.TypeOf(MyFunction)
argType := reflectedFunction.In(0)
reflectedParameter := reflect.New(argType)
actual := reflectedParameter.Interface()
fmt.Println(actual)
expected := &MyStruct{}
fmt.Println(expected)
}
func MyFunction(myStruct *MyStruct) {
}
If you execute it, you'll see that they contain different info:
0xc00000e028 // actual
&{} // expected
This question isn't about why I would like to do this, so please avoid recommending not doing it, etc.

Answer 1

In your code, actual is a interface{} value containing a *MyStruct. As the name and documentation indicate, reflectedParameter.Interface() returns an interface{}.
using reflection I want to create a variable that contains exactly same as x := &MyStruct{} would contain.
Then you'll have to type assert it:
actual := reflectedParameter.Elem().Interface().(*MyStruct)

Answer 2

reflect.New creates a pointer to a new zero value of the reflected type. In your example that type is already a *MyStruct, so the value of your actual winds up being a representation of a **MyStruct, as seen in https://play.golang.org/p/Nyuc0mYmgkZ. Taking the .Elem() of that results in the correct type again, but you end up with a nil pointer (*MyStruct)(nil).
You need to take the .Elem() if that first type if you want to create a new pointer value.
reflectedParameter := reflect.New(argType.Elem())
https://play.golang.org/p/QzwTFUH3HTs
reflectedFunction := reflect.TypeOf(MyFunction)
argType := reflectedFunction.In(0)
reflectedParameter := reflect.New(argType.Elem())
actual := reflectedParameter.Interface()
fmt.Printf("%#v\n", actual)
expected := &MyStruct{}
fmt.Printf("%#v\n", expected)
Which prints
&main.MyStruct{}
&main.MyStruct{}