.

go/internal/xtracing/tracetest/chan.go

@@ -19,7 +19,6 @@
 
 package tracetest
 // synchronous channels.
-// XXX move back to tracetest.go ? -> likely yes
 
 import (
 	"errors"
@@ -128,7 +127,6 @@ func (ch *_chan) recv() *_Msg {
 }
 
 
-// XXX -> Unpause? Cont? Continue?
 // Ack acknowledges the event was processed and unblocks producer goroutine.
 func (m *_Msg) Ack() {
 	m.ack <- nil

go/internal/xtracing/tracetest/tracetest.go

@@ -449,7 +449,9 @@ func (t *T) xget1(stream string, eventp interface{}) *_Msg {
 	ch := t.chanForStream(stream)
 	t.mu.Unlock()
 
-	// XXX ch == nil -> no longer operational
+	if ch == nil {
+		t.Fatalf("%s: recv: cancled (test failed)", stream)
+	}
 
 	return ch.RecvInto(eventp)
 }