Initial commit: Go 1.23 release state

test/fixedbugs/issue27518a.go

@@ -0,0 +1,45 @@
+// run
+
+// Copyright 2018 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"
+)
+
+var nilp *int
+var forceHeap interface{}
+
+func main() {
+	// x is a pointer on the stack to heap-allocated memory.
+	x := new([32]*int)
+	forceHeap = x
+	forceHeap = nil
+
+	// Push a defer to be run when we panic below.
+	defer func() {
+		// Ignore the panic.
+		recover()
+		// Force a stack walk. Go 1.11 will fail because x is now
+		// considered live again.
+		runtime.GC()
+	}()
+	// Make x live at the defer's PC.
+	runtime.KeepAlive(x)
+
+	// x is no longer live. Garbage collect the [32]*int on the
+	// heap.
+	runtime.GC()
+	// At this point x's dead stack slot points to dead memory.
+
+	// Trigger a sigpanic. Since this is an implicit panic, we
+	// don't have an explicit liveness map here.
+	// Traceback used to use the liveness map of the most recent defer,
+	// but in that liveness map, x will be live again even though
+	// it points to dead memory. The fix is to use the liveness
+	// map of a deferreturn call instead.
+	*nilp = 0
+}