struct.go

// run -gcflags=-G=3

// Copyright 2021 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package main

import (
	"fmt"
)

type E[T any] struct {
	v T
}

type S1 struct {
	E[int]
	v string
}

type Eint = E[int]
type Ebool = E[bool]

type S2 struct {
	Eint
	Ebool
	v string
}

type S3 struct {
	*E[int]
}

func main() {
	s1 := S1{Eint{2}, "foo"}
	if got, want := s1.E.v, 2; got != want {
		panic(fmt.Sprintf("got %d, want %d", got, want))
	}
	s2 := S2{Eint{3}, Ebool{true}, "foo"}
	if got, want := s2.Eint.v, 3; got != want {
		panic(fmt.Sprintf("got %d, want %d", got, want))
	}
	var s3 S3
	s3.E = &Eint{4}
	if got, want := s3.E.v, 4; got != want {
		panic(fmt.Sprintf("got %d, want %d", got, want))
	}
}