1 files changed, 37 insertions, 0 deletions
diff --git a/test/typeparam/issue54456.go b/test/typeparam/issue54456.go
new file mode 100644
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--- /dev/null
+++ b/test/typeparam/issue54456.go
@@ -0,0 +1,37 @@
+// 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.
+
+// The Go 1.18 frontend failed to disambiguate instantiations of
+// different, locally defined generic types with the same name.
+//
+// The unified frontend also exposed the scope-disambiguation mangling
+// to end users in reflect data.
+
+package main
+
+import (
+	"reflect"
+)
+
+func one() any { type T[_ any] int; return T[int](0) }
+func two() any { type T[_ any] int; return T[int](0) }
+
+func main() {
+	p, q := one(), two()
+
+	// p and q have different dynamic types; this comparison should
+	// evaluate false.
+	if p == q {
+		panic("bad type identity")
+	}
+
+	for _, x := range []any{p, q} {
+		// The names here should not contain "·1" or "·2".
+		if name := reflect.TypeOf(x).String(); name != "main.T[int]" {
+			panic(name)
+		}
+	}
+}