gc: remove func, map compare

R=ken, ken
CC=golang-dev
https://golang.org/cl/5373079
diff --git a/test/cmp6.go b/test/cmp6.go
index b3ea8ff..6b13cac 100644
--- a/test/cmp6.go
+++ b/test/cmp6.go
@@ -11,7 +11,7 @@
 type T1 *int
 type T2 *int
 
-type T3 struct {}
+type T3 struct{}
 
 var t3 T3
 
@@ -21,12 +21,12 @@
 	// so chan int can be compared against
 	// directional channels but channel of different
 	// direction cannot be compared against each other.
-	var c1 chan <-int
+	var c1 chan<- int
 	var c2 <-chan int
 	var c3 chan int
-	
-	use(c1 == c2)	// ERROR "invalid operation|incompatible"
-	use(c2 == c1)	// ERROR "invalid operation|incompatible"
+
+	use(c1 == c2) // ERROR "invalid operation|incompatible"
+	use(c2 == c1) // ERROR "invalid operation|incompatible"
 	use(c1 == c3)
 	use(c2 == c2)
 	use(c3 == c1)
@@ -36,14 +36,22 @@
 	var p1 T1
 	var p2 T2
 	var p3 *int
-	
-	use(p1 == p2)	// ERROR "invalid operation|incompatible"
-	use(p2 == p1)	// ERROR "invalid operation|incompatible"
+
+	use(p1 == p2) // ERROR "invalid operation|incompatible"
+	use(p2 == p1) // ERROR "invalid operation|incompatible"
 	use(p1 == p3)
 	use(p2 == p2)
 	use(p3 == p1)
 	use(p3 == p2)
-	
+
 	// Comparison of structs should have a good message
-	use(t3 == t3)	// ERROR "struct|expected"
+	use(t3 == t3) // ERROR "struct|expected"
+
+	// Slices, functions, and maps too.
+	var x []int
+	var f func()
+	var m map[int]int
+	use(x == x) // ERROR "slice can only be compared to nil"
+	use(f == f) // ERROR "func can only be compared to nil"
+	use(m == m) // ERROR "map can only be compared to nil"
 }