1 files changed, 38 insertions, 0 deletions
diff --git a/test/typeparam/issue48317.go b/test/typeparam/issue48317.go
new file mode 100644
index 0000000000..c8f088dc7a
--- /dev/null
+++ b/test/typeparam/issue48317.go
@@ -0,0 +1,38 @@
+// run -gcflags="-G=3"
+
+// 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 (
+	"encoding/json"
+)
+
+type A[T any] struct {
+	F1 string `json:"t1"`
+	F2 T      `json:"t2"`
+	B  B      `json:"t3"`
+}
+
+type B struct {
+	F4 int `json:"t4"`
+}
+
+func a[T any]() {
+	data := `{"t1":"1","t2":2,"t3":{"t4":4}}`
+	a1 := A[T]{}
+	if err := json.Unmarshal([]byte(data), &a1); err != nil {
+		panic(err)
+	}
+	if bytes, err := json.Marshal(&a1); err != nil {
+		panic(err)
+	} else if string(bytes) != data {
+		panic(string(bytes))
+	}
+}
+
+func main() {
+	a[int]()
+}