Go Interfaces & Embedding

Interface satisfaction is implicit and structural. Embedding promotes the inner type's method set; the receiver stays the inner type. Composition, not inheritance — no virtual dispatch.

Type switch vs assertion

switch t := v.(type) {
case int:   use(t)      // t is int
case *Foo:  use(t)      // t is *Foo
default:                // t keeps interface type
}

s, ok := v.(string)     // comma-ok avoids panic

Bare v.(string) panics on mismatch.

Compile-time interface compliance