Behaviour of nil receiver in method in Golang

package main
import (
	"fmt"
)
type I interface {
	M()
}
type T struct {
}
func (t *T) M() {
	fmt.Println(t == nil)
}
func main() {
	var i I
	var t *T
	i = t
	fmt.Println(i == nil)
	i.M()
}

The result is false and true.

The value in both cases is nil and type is *main.T.

I understand that in the first case i == nil is false because the variable i does not have a nil type.

I do not understand why t == nil is true inside the method M().

In the first case, i==nil is false, because i is an interface whose type is T and whose value is nil. For an interface to be equal to the literal value nil, it has to have both type and value nil. Here, i has non-nil type.

In the second case, the receiver is simply nil, because the receiver of the function M is a value of type *T whose value is nil.