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-rw-r--r--test/typeparam/issue47272.go55
1 files changed, 55 insertions, 0 deletions
diff --git a/test/typeparam/issue47272.go b/test/typeparam/issue47272.go
new file mode 100644
index 0000000000..6771cb9901
--- /dev/null
+++ b/test/typeparam/issue47272.go
@@ -0,0 +1,55 @@
+// 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 (
+ "errors"
+ "fmt"
+)
+
+type Option[T any] struct {
+ ok bool
+ val T
+}
+
+func (o Option[T]) String() string {
+ if o.ok {
+ return fmt.Sprintf("Some(%v)", o.val)
+ }
+ return "None"
+}
+
+func Some[T any](val T) Option[T] { return Option[T]{ok: true, val: val} }
+func None[T any]() Option[T] { return Option[T]{ok: false} }
+
+type Result[T, E any] struct {
+ ok bool
+ val T
+ err E
+}
+
+func (r Result[T, E]) String() string {
+ if r.ok {
+ return fmt.Sprintf("Ok(%v)", r.val)
+ }
+ return fmt.Sprintf("Err(%v)", r.err)
+}
+
+func Ok[T, E any](val T) Result[T, E] { return Result[T, E]{ok: true, val: val} }
+func Err[T, E any](err E) Result[T, E] { return Result[T, E]{ok: false, err: err} }
+
+func main() {
+ a := Some[int](1)
+ b := None[int]()
+ fmt.Println(a, b)
+
+ x := Ok[int, error](1)
+ y := Err[int, error](errors.New("test"))
+ fmt.Println(x, y)
+ // fmt.Println(x)
+ _, _, _, _ = a, b, x, y
+}