trie: unset the edge valuenode as well

trie/proof.go

@@ -264,11 +264,13 @@ func unset(root node, rest []byte, removeLeft bool) {
 		unset(rn.Children[rest[0]], rest[1:], removeLeft)
 	case *shortNode:
 		rn.flags = nodeFlag{dirty: true}
+		if _, ok := rn.Val.(valueNode); ok {
+			rn.Val = nil
+			return
+		}
 		unset(rn.Val, rest[len(rn.Key):], removeLeft)
-	case hashNode, nil:
+	case hashNode, nil, valueNode:
 		panic("it shouldn't happen")
-	case valueNode:
-		return
 	}
 }
 

trie/proof_test.go

@@ -164,7 +164,7 @@ func TestBadRangeProof(t *testing.T) {
 			keys = append(keys, entries[i].k)
 			vals = append(vals, entries[i].v)
 		}
-		testcase := mrand.Intn(4)
+		testcase := mrand.Intn(6)
 		var index int
 		switch testcase {
 		case 0:
@@ -188,6 +188,14 @@ func TestBadRangeProof(t *testing.T) {
 			index = mrand.Intn(end - start)
 			keys[index] = entries[len(entries)-1].k
 			vals[index] = entries[len(entries)-1].v
+		case 4:
+			// Set random key to nil
+			index = mrand.Intn(end - start)
+			keys[index] = nil
+		case 5:
+			// Set random value to nil
+			index = mrand.Intn(end - start)
+			vals[index] = nil
 		}
 		err := VerifyRangeProof(trie.Hash(), keys, vals, firstProof, lastProof)
 		if err == nil {