accounts/abi: fix MakeTopics mutation of big.Int inputs

accounts/abi/topics.go

@@ -42,7 +42,7 @@ func MakeTopics(query ...[]interface{}) ([][]common.Hash, error) {
 			case common.Address:
 				copy(topic[common.HashLength-common.AddressLength:], rule[:])
 			case *big.Int:
-				copy(topic[:], math.U256Bytes(rule))
+				copy(topic[:], math.U256Bytes(new(big.Int).Set(rule)))
 			case bool:
 				if rule {
 					topic[common.HashLength-1] = 1

accounts/abi/topics_test.go

@@ -149,6 +149,23 @@ func TestMakeTopics(t *testing.T) {
 			}
 		})
 	}
+
+	t.Run("does not mutate big.Int", func(t *testing.T) {
+		t.Parallel()
+		want := [][]common.Hash{{common.HexToHash("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff")}}
+
+		in := big.NewInt(-1)
+		got, err := MakeTopics([]interface{}{in})
+		if err != nil {
+			t.Fatalf("makeTopics() error = %v", err)
+		}
+		if !reflect.DeepEqual(got, want) {
+			t.Fatalf("makeTopics() = %v, want %v", got, want)
+		}
+		if orig := big.NewInt(-1); in.Cmp(orig) != 0 {
+			t.Fatalf("makeTopics() mutated an input parameter from %v to %v", orig, in)
+		}
+	})
 }
 
 type args struct {

signer/core/apitypes/types.go

@@ -676,7 +676,7 @@ func (typedData *TypedData) EncodePrimitiveValue(encType string, encValue interf
 		if err != nil {
 			return nil, err
 		}
-		return math.U256Bytes(b), nil
+		return math.U256Bytes(new(big.Int).Set(b)), nil
 	}
 	return nil, fmt.Errorf("unrecognized type '%s'", encType)
 }