1 files changed, 29 insertions, 0 deletions
diff --git a/test/fixedbugs/issue22781.go b/test/fixedbugs/issue22781.go
new file mode 100644
index 0000000..5ad8239
--- /dev/null
+++ b/test/fixedbugs/issue22781.go
@@ -0,0 +1,29 @@
+// run
+
+// Copyright 2017 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 "runtime/debug"
+
+type T struct {
+	// >= 16 bytes to avoid tiny alloc.
+	a, b int
+}
+
+func main() {
+	debug.SetGCPercent(1)
+	for i := 0; i < 100000; i++ {
+		m := make(map[*T]struct{}, 0)
+		for j := 0; j < 20; j++ {
+			// During the call to mapassign_fast64, the key argument
+			// was incorrectly treated as a uint64. If the stack was
+			// scanned during that call, the only pointer to k was
+			// missed, leading to *k being collected prematurely.
+			k := new(T)
+			m[k] = struct{}{}
+		}
+	}
+}