Reverse logic operators.

app/Rules/IsTransferAccount.php

@@ -71,6 +71,6 @@ class IsTransferAccount implements Rule
         $validAccount = $validator->validateSource((int)$value, null, null);
         Log::debug(sprintf('Search by id (%d), result is %s.', (int)$value, var_export($validAccount, true)));
 
-        return !(false === $validAccount);
+        return false !== $validAccount;
     }
 }

app/Rules/ZeroOrMore.php

@@ -60,6 +60,6 @@ class ZeroOrMore implements Rule
         }
         $res = bccomp('0', $value);
 
-        return !($res > 0);
+        return $res <= 0;
     }
 }