gofix -r mapdelete

R=golang-dev, r, adg, r, cw
CC=golang-dev
https://golang.org/cl/5266045
diff --git a/test/nil.go b/test/nil.go
index 30cc270..efcf4f7 100644
--- a/test/nil.go
+++ b/test/nil.go
@@ -150,7 +150,7 @@
 		m[2] = 3
 	})
 	shouldPanic(func() {
-		m[2] = 0, false
+		delete(m, 2)
 	})
 }