2 files changed, 43 insertions, 0 deletions
diff --git a/src/internal/synctest/synctest_test.go b/src/internal/synctest/synctest_test.go
index c0e126e3fc..7c8fd7ef9e 100644
--- a/src/internal/synctest/synctest_test.go
+++ b/src/internal/synctest/synctest_test.go
@@ -263,6 +263,46 @@ func TestChannelFromOutsideBubble(t *testing.T) {
 	}
 }
 
+func TestChannelMovedOutOfBubble(t *testing.T) {
+	for _, test := range []struct {
+		desc      string
+		f         func(chan struct{})
+		wantPanic string
+	}{{
+		desc: "receive",
+		f: func(ch chan struct{}) {
+			<-ch
+		},
+		wantPanic: "receive on synctest channel from outside bubble",
+	}, {
+		desc: "send",
+		f: func(ch chan struct{}) {
+			ch <- struct{}{}
+		},
+		wantPanic: "send on synctest channel from outside bubble",
+	}, {
+		desc: "close",
+		f: func(ch chan struct{}) {
+			close(ch)
+		},
+		wantPanic: "close of synctest channel from outside bubble",
+	}} {
+		t.Run(test.desc, func(t *testing.T) {
+			donec := make(chan struct{})
+			ch := make(chan chan struct{})
+			go func() {
+				defer close(donec)
+				defer wantPanic(t, test.wantPanic)
+				test.f(<-ch)
+			}()
+			synctest.Run(func() {
+				ch <- make(chan struct{})
+			})
+			<-donec
+		})
+	}
+}
+
 func TestTimerFromInsideBubble(t *testing.T) {
 	for _, test := range []struct {
 		desc      string
diff --git a/src/runtime/chan.go b/src/runtime/chan.go
index cb2737d096..63d8044b44 100644
--- a/src/runtime/chan.go
+++ b/src/runtime/chan.go
@@ -415,6 +415,9 @@ func closechan(c *hchan) {
 	if c == nil {
 		panic(plainError("close of nil channel"))
 	}
+	if c.synctest && getg().bubble == nil {
+		panic(plainError("close of synctest channel from outside bubble"))
+	}
 
 	lock(&c.lock)
 	if c.closed != 0 {