runtime: require explicit GC layouts

src/reflect/value_test.go

@@ -994,6 +994,20 @@ func TestTypeAssertPanic(t *testing.T) {
 	})
 }
 
+type tinyMakeChanElement struct {
+	ptr  *int
+	text string
+}
+
+var tinyMakeChanChurn []*int
+
+//go:noinline
+func fillTinyMakeChan(ch chan tinyMakeChanElement) {
+	value := new(int)
+	*value = 42
+	ch <- tinyMakeChanElement{ptr: value, text: "hello"}
+}
+
 func TestTinyMakeChan(t *testing.T) {
 	// Value.Send and Value.Recv are not implemented yet, so the channel is
 	// exercised through Interface(): that proves MakeChan returns a working
@@ -1027,6 +1041,22 @@ func TestTinyMakeChan(t *testing.T) {
 		}
 	})
 
+	t.Run("buffered pointers survive GC", func(t *testing.T) {
+		v := MakeChan(TypeOf(make(chan tinyMakeChanElement)), 1)
+		ch := v.Interface().(chan tinyMakeChanElement)
+		fillTinyMakeChan(ch)
+		runtime.GC()
+		tinyMakeChanChurn = make([]*int, 128)
+		for i := range tinyMakeChanChurn {
+			tinyMakeChanChurn[i] = new(int)
+		}
+
+		got := <-ch
+		if *got.ptr != 42 || got.text != "hello" {
+			t.Errorf("<-ch=%v, want {42 hello}", got)
+		}
+	})
+
 	t.Run("unbuffered", func(t *testing.T) {
 		v := MakeChan(TypeOf(make(chan string)), 0)
 		if got, want := v.Cap(), 0; got != want {