1 files changed, 50 insertions, 0 deletions
diff --git a/test/typeparam/issue52026.go b/test/typeparam/issue52026.go
new file mode 100644
index 0000000..db8999a
--- /dev/null
+++ b/test/typeparam/issue52026.go
@@ -0,0 +1,50 @@
+// run
+
+// Copyright 2022 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
+
+func returnOption[T any](n int) Option[T] {
+	if n == 1 {
+		return Some[T]{}
+	} else {
+		return None{}
+	}
+}
+
+type Option[T any] interface {
+	sealedOption()
+}
+
+type Some[T any] struct {
+	val T
+}
+
+func (s Some[T]) Value() T {
+	return s.val
+}
+
+func (s Some[T]) sealedOption() {}
+
+type None struct{}
+
+func (s None) sealedOption() {}
+
+func main() {
+	s := returnOption[int](1)
+	_ = s.(Some[int])
+
+	s = returnOption[int](0)
+	_ = s.(None)
+
+	switch (any)(s).(type) {
+	case Some[int]:
+		panic("s is a Some[int]")
+	case None:
+		// ok
+	default:
+		panic("oops")
+	}
+}