Set internal linkage and keeping default visibility for anonymous functions

testdata/generics/value/value.go

@@ -0,0 +1,53 @@
+package value
+
+type (
+	Value[T any] interface {
+		Get(Callback[T], Callback[T])
+	}
+
+	Callback[T any] func(T)
+
+	Transform[S any, D any] func(S) D
+)
+
+func New[T any](v T) Value[T] {
+	return &value[T]{
+		v: v,
+	}
+}
+
+type value[T any] struct {
+	v T
+}
+
+func (v *value[T]) Get(fn1, fn2 Callback[T]) {
+	// For example purposes.
+	// Normally would be asynchronous callback.
+	fn1(v.v)
+	fn2(v.v)
+}
+
+func Map[S, D any](v Value[S], tx Transform[S, D]) Value[D] {
+	return &mapper[S, D]{
+		v:  v,
+		tx: tx,
+	}
+}
+
+type mapper[S, D any] struct {
+	v  Value[S]
+	tx Transform[S, D]
+}
+
+func (m *mapper[S, D]) Get(fn1, fn2 Callback[D]) {
+	// two callbacks are passed to generate more than
+	// one anonymous function symbol name.
+	m.v.Get(func(v S) {
+		// anonymous function inside of anonymous function.
+		func() {
+			fn1(m.tx(v))
+		}()
+	}, func(v S) {
+		fn2(m.tx(v))
+	})
+}