genembed2.go

     1  // run
     2  
     3  // Copyright 2021 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  // Test for declaration and use of a parameterized embedded field.
     8  
     9  package main
    10  
    11  import (
    12  	"fmt"
    13  	"sync"
    14  )
    15  
    16  type MyStruct[T any] struct {
    17  	val T
    18  }
    19  
    20  type Lockable[T any] struct {
    21  	MyStruct[T]
    22  	mu sync.Mutex
    23  }
    24  
    25  // Get returns the value stored in a Lockable.
    26  func (l *Lockable[T]) Get() T {
    27  	l.mu.Lock()
    28  	defer l.mu.Unlock()
    29  	return l.MyStruct.val
    30  }
    31  
    32  // Set sets the value in a Lockable.
    33  func (l *Lockable[T]) Set(v T) {
    34  	l.mu.Lock()
    35  	defer l.mu.Unlock()
    36  	l.MyStruct = MyStruct[T]{v}
    37  }
    38  
    39  func main() {
    40  	var li Lockable[int]
    41  
    42  	li.Set(5)
    43  	if got, want := li.Get(), 5; got != want {
    44  		panic(fmt.Sprintf("got %d, want %d", got, want))
    45  	}
    46  }
    47
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