Fixes issues with NoneType and restricts rlp version (#1567)

* Fix when args are NoneType

* Fix rlp

mythril/analysis/module/modules/integer.py

@@ -162,7 +162,9 @@ class IntegerArithmetics(DetectionModule):
     def _handle_exp(self, state):
         op0, op1 = self._get_args(state)
 
-        if op1.value == 0 or op0.value < 2:
+        if (op1.symbolic is False and op1.value == 0) or (
+            op0.symbolic is False and op0.value < 2
+        ):
             return
         if op0.symbolic and op1.symbolic:
             constraint = And(

requirements.txt

@@ -27,7 +27,7 @@ pyparsing<3,>=2.0.2
 pytest-cov
 pytest_mock
 requests
-rlp
+rlp<3.0.0
 semantic_version
 transaction>=2.2.1
 typing-extensions<4,>=3.7.4