How to Avoid Compilation Errors When Accessing Embedded Struct Fields in Go?

Embedded Struct Type Field Access

When defining new struct types, it is possible to embed other structs as fields. This can be useful for creating complex data structures or inheriting functionality. However, accessing embedded struct fields can sometimes lead to compilation errors due to pointer handling.

Consider the following code:

<code class="go">type Engine struct {
    power int
}

type Tires struct {
    number int
}

type Cars struct {
    *Engine
    Tires
}

func main() {
    car := new(Cars)
    car.number = 4
    car.power = 342
    fmt.Println(car)
}</code>

This code attempts to embed an Engine struct as a pointer field (*Engine) in the Cars struct. While the syntax is correct, compiling the code results in the following error:

panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x0 pc=0x23bb]

To resolve this issue, it is necessary to correctly initialize the embedded Engine field. This can be achieved using pointers to the embedded struct:

<code class="go">func main() {
    car := new(Cars)
    car.Engine = new(Engine) // Initialize the Engine pointer
    car.power = 342
    car.number = 4
    fmt.Println(car)
}</code>

Now, the code compiles successfully and accesses the embedded field "power" without encountering any errors.

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