1 files changed, 50 insertions, 0 deletions
diff --git a/test/typeparam/lockable.go b/test/typeparam/lockable.go
new file mode 100644
index 0000000..2b50e2c
--- /dev/null
+++ b/test/typeparam/lockable.go
@@ -0,0 +1,50 @@
+// run
+
+// 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 "sync"
+
+// A Lockable is a value that may be safely simultaneously accessed
+// from multiple goroutines via the Get and Set methods.
+type Lockable[T any] struct {
+	x  T
+	mu sync.Mutex
+}
+
+// Get returns the value stored in a Lockable.
+func (l *Lockable[T]) get() T {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	return l.x
+}
+
+// set sets the value in a Lockable.
+func (l *Lockable[T]) set(v T) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.x = v
+}
+
+func main() {
+	sl := Lockable[string]{x: "a"}
+	if got := sl.get(); got != "a" {
+		panic(got)
+	}
+	sl.set("b")
+	if got := sl.get(); got != "b" {
+		panic(got)
+	}
+
+	il := Lockable[int]{x: 1}
+	if got := il.get(); got != 1 {
+		panic(got)
+	}
+	il.set(2)
+	if got := il.get(); got != 2 {
+		panic(got)
+	}
+}