package main

type Fooer interface {
        Foo()
}

// HandleFooer is intended to show that passing interface will not rasie an allocation.
func HandleFooer(f Fooer) {
        // Passing interface Fooer<*Concrete> will not raise an allocation 
        // even if we do some work on f, such as f.(*Concrete).Foo().
}

type Concrete byte

func (c Concrete) Foo() {}

package main

import "testing"

func BenchmarkCallFooer(b *testing.B) {
        for i := 0; i < b.N; i++ {
                var c Concrete = 42// Moved to heap.
                Fooer(&c).Foo()
        }
}

func BenchmarkPassFooer(b *testing.B) {
        for i := 0; i < b.N; i++ {
                var c Concrete = 42 // Not moved to heap.
                HandleFooer(Fooer(&c))
        }
}