diff --git a/slither/__main__.py b/slither/__main__.py
index 528a93e8f..a5d51dcd6 100644
--- a/slither/__main__.py
+++ b/slither/__main__.py
@@ -66,7 +66,7 @@ def process_single(
     args: argparse.Namespace,
     detector_classes: List[Type[AbstractDetector]],
     printer_classes: List[Type[AbstractPrinter]],
-) -> Tuple[Slither, List[Dict], List[Dict], int]:
+) -> Tuple[Slither, List[Dict], List[Output], int]:
     """
     The core high-level code for running Slither static analysis.
 
@@ -89,7 +89,7 @@ def process_all(
     args: argparse.Namespace,
     detector_classes: List[Type[AbstractDetector]],
     printer_classes: List[Type[AbstractPrinter]],
-) -> Tuple[List[Slither], List[Dict], List[Dict], int]:
+) -> Tuple[List[Slither], List[Dict], List[Output], int]:
     compilations = compile_all(target, **vars(args))
     slither_instances = []
     results_detectors = []
@@ -144,23 +144,6 @@ def _process(
     return slither, results_detectors, results_printers, analyzed_contracts_count
 
 
-# TODO: delete me?
-def process_from_asts(
-    filenames: List[str],
-    args: argparse.Namespace,
-    detector_classes: List[Type[AbstractDetector]],
-    printer_classes: List[Type[AbstractPrinter]],
-) -> Tuple[Slither, List[Dict], List[Dict], int]:
-    all_contracts: List[str] = []
-
-    for filename in filenames:
-        with open(filename, encoding="utf8") as file_open:
-            contract_loaded = json.load(file_open)
-            all_contracts.append(contract_loaded["ast"])
-
-    return process_single(all_contracts, args, detector_classes, printer_classes)
-
-
 # endregion
 ###################################################################################
 ###################################################################################
@@ -608,9 +591,6 @@ def parse_args(
         default=False,
     )
 
-    # if the json is splitted in different files
-    parser.add_argument("--splitted", help=argparse.SUPPRESS, action="store_true", default=False)
-
     # Disable the throw/catch on partial analyses
     parser.add_argument(
         "--disallow-partial", help=argparse.SUPPRESS, action="store_true", default=False
@@ -626,7 +606,7 @@ def parse_args(
     args.filter_paths = parse_filter_paths(args)
 
     # Verify our json-type output is valid
-    args.json_types = set(args.json_types.split(","))
+    args.json_types = set(args.json_types.split(","))  # type:ignore
     for json_type in args.json_types:
         if json_type not in JSON_OUTPUT_TYPES:
             raise Exception(f'Error: "{json_type}" is not a valid JSON result output type.')
@@ -697,14 +677,14 @@ class OutputWiki(argparse.Action):  # pylint: disable=too-few-public-methods
 
 
 class FormatterCryticCompile(logging.Formatter):
-    def format(self, record):
+    def format(self, record: logging.LogRecord) -> str:
         # for i, msg in enumerate(record.msg):
         if record.msg.startswith("Compilation warnings/errors on "):
-            txt = record.args[1]
-            txt = txt.split("\n")
+            txt = record.args[1]  # type:ignore
+            txt = txt.split("\n")  # type:ignore
             txt = [red(x) if "Error" in x else x for x in txt]
             txt = "\n".join(txt)
-            record.args = (record.args[0], txt)
+            record.args = (record.args[0], txt)  # type:ignore
         return super().format(record)
 
 
@@ -747,7 +727,7 @@ def main_impl(
     set_colorization_enabled(False if args.disable_color else sys.stdout.isatty())
 
     # Define some variables for potential JSON output
-    json_results = {}
+    json_results: Dict[str, Any] = {}
     output_error = None
     outputting_json = args.json is not None
     outputting_json_stdout = args.json == "-"
@@ -796,7 +776,7 @@ def main_impl(
     crytic_compile_error.setLevel(logging.INFO)
 
     results_detectors: List[Dict] = []
-    results_printers: List[Dict] = []
+    results_printers: List[Output] = []
     try:
         filename = args.filename
 
@@ -809,26 +789,17 @@ def main_impl(
             number_contracts = 0
 
             slither_instances = []
-            if args.splitted:
+            for filename in filenames:
                 (
                     slither_instance,
-                    results_detectors,
-                    results_printers,
-                    number_contracts,
-                ) = process_from_asts(filenames, args, detector_classes, printer_classes)
+                    results_detectors_tmp,
+                    results_printers_tmp,
+                    number_contracts_tmp,
+                ) = process_single(filename, args, detector_classes, printer_classes)
+                number_contracts += number_contracts_tmp
+                results_detectors += results_detectors_tmp
+                results_printers += results_printers_tmp
                 slither_instances.append(slither_instance)
-            else:
-                for filename in filenames:
-                    (
-                        slither_instance,
-                        results_detectors_tmp,
-                        results_printers_tmp,
-                        number_contracts_tmp,
-                    ) = process_single(filename, args, detector_classes, printer_classes)
-                    number_contracts += number_contracts_tmp
-                    results_detectors += results_detectors_tmp
-                    results_printers += results_printers_tmp
-                    slither_instances.append(slither_instance)
 
         # Rely on CryticCompile to discern the underlying type of compilations.
         else:
diff --git a/slither/analyses/data_dependency/data_dependency.py b/slither/analyses/data_dependency/data_dependency.py
index b2a154672..448ee393a 100644
--- a/slither/analyses/data_dependency/data_dependency.py
+++ b/slither/analyses/data_dependency/data_dependency.py
@@ -4,6 +4,7 @@
 from collections import defaultdict
 from typing import Union, Set, Dict, TYPE_CHECKING
 
+from slither.core.cfg.node import Node
 from slither.core.declarations import (
     Contract,
     Enum,
@@ -12,6 +13,7 @@ from slither.core.declarations import (
     SolidityVariable,
     SolidityVariableComposed,
     Structure,
+    FunctionContract,
 )
 from slither.core.declarations.solidity_import_placeholder import SolidityImportPlaceHolder
 from slither.core.variables.top_level_variable import TopLevelVariable
@@ -40,25 +42,37 @@ if TYPE_CHECKING:
 
 
 Variable_types = Union[Variable, SolidityVariable]
+# TODO refactor the data deps to be better suited for top level function object
+# Right now we allow to pass a node to ease the API, but we need something
+# better
+# The deps propagation for top level elements is also not working as expected
+Context_types_API = Union[Contract, Function, Node]
 Context_types = Union[Contract, Function]
 
 
 def is_dependent(
     variable: Variable_types,
     source: Variable_types,
-    context: Context_types,
+    context: Context_types_API,
     only_unprotected: bool = False,
 ) -> bool:
     """
+    If Node is provided as context, the context will be the broader context, either the contract or the function,
+    depending on if the node is in a top level function or not
+
     Args:
         variable (Variable)
         source (Variable)
-        context (Contract|Function)
+        context (Contract|Function|Node).
         only_unprotected (bool): True only unprotected function are considered
     Returns:
         bool
     """
-    assert isinstance(context, (Contract, Function))
+    assert isinstance(context, (Contract, Function, Node))
+    if isinstance(context, Node):
+        func = context.function
+        context = func.contract if isinstance(func, FunctionContract) else func
+
     if isinstance(variable, Constant):
         return False
     if variable == source:
@@ -76,10 +90,13 @@ def is_dependent(
 def is_dependent_ssa(
     variable: Variable_types,
     source: Variable_types,
-    context: Context_types,
+    context: Context_types_API,
     only_unprotected: bool = False,
 ) -> bool:
     """
+    If Node is provided as context, the context will be the broader context, either the contract or the function,
+    depending on if the node is in a top level function or not
+
     Args:
         variable (Variable)
         taint (Variable)
@@ -88,7 +105,10 @@ def is_dependent_ssa(
     Returns:
         bool
     """
-    assert isinstance(context, (Contract, Function))
+    assert isinstance(context, (Contract, Function, Node))
+    if isinstance(context, Node):
+        func = context.function
+        context = func.contract if isinstance(func, FunctionContract) else func
     context_dict = context.context
     if isinstance(variable, Constant):
         return False
@@ -112,11 +132,14 @@ GENERIC_TAINT = {
 
 def is_tainted(
     variable: Variable_types,
-    context: Context_types,
+    context: Context_types_API,
     only_unprotected: bool = False,
     ignore_generic_taint: bool = False,
 ) -> bool:
     """
+    If Node is provided as context, the context will be the broader context, either the contract or the function,
+    depending on if the node is in a top level function or not
+
         Args:
         variable
         context (Contract|Function)
@@ -124,7 +147,10 @@ def is_tainted(
     Returns:
         bool
     """
-    assert isinstance(context, (Contract, Function))
+    assert isinstance(context, (Contract, Function, Node))
+    if isinstance(context, Node):
+        func = context.function
+        context = func.contract if isinstance(func, FunctionContract) else func
     assert isinstance(only_unprotected, bool)
     if isinstance(variable, Constant):
         return False
@@ -139,11 +165,14 @@ def is_tainted(
 
 def is_tainted_ssa(
     variable: Variable_types,
-    context: Context_types,
+    context: Context_types_API,
     only_unprotected: bool = False,
     ignore_generic_taint: bool = False,
-):
+) -> bool:
     """
+    If Node is provided as context, the context will be the broader context, either the contract or the function,
+    depending on if the node is in a top level function or not
+
     Args:
         variable
         context (Contract|Function)
@@ -151,7 +180,10 @@ def is_tainted_ssa(
     Returns:
         bool
     """
-    assert isinstance(context, (Contract, Function))
+    assert isinstance(context, (Contract, Function, Node))
+    if isinstance(context, Node):
+        func = context.function
+        context = func.contract if isinstance(func, FunctionContract) else func
     assert isinstance(only_unprotected, bool)
     if isinstance(variable, Constant):
         return False
@@ -166,18 +198,23 @@ def is_tainted_ssa(
 
 def get_dependencies(
     variable: Variable_types,
-    context: Context_types,
+    context: Context_types_API,
     only_unprotected: bool = False,
 ) -> Set[Variable]:
     """
     Return the variables for which `variable` depends on.
+    If Node is provided as context, the context will be the broader context, either the contract or the function,
+    depending on if the node is in a top level function or not
 
     :param variable: The target
     :param context: Either a function (interprocedural) or a contract (inter transactional)
     :param only_unprotected: True if consider only protected functions
     :return: set(Variable)
     """
-    assert isinstance(context, (Contract, Function))
+    assert isinstance(context, (Contract, Function, Node))
+    if isinstance(context, Node):
+        func = context.function
+        context = func.contract if isinstance(func, FunctionContract) else func
     assert isinstance(only_unprotected, bool)
     if only_unprotected:
         return context.context[KEY_NON_SSA_UNPROTECTED].get(variable, set())
@@ -185,16 +222,21 @@ def get_dependencies(
 
 
 def get_all_dependencies(
-    context: Context_types, only_unprotected: bool = False
+    context: Context_types_API, only_unprotected: bool = False
 ) -> Dict[Variable, Set[Variable]]:
     """
     Return the dictionary of dependencies.
+    If Node is provided as context, the context will be the broader context, either the contract or the function,
+    depending on if the node is in a top level function or not
 
     :param context: Either a function (interprocedural) or a contract (inter transactional)
     :param only_unprotected: True if consider only protected functions
     :return: Dict(Variable, set(Variable))
     """
-    assert isinstance(context, (Contract, Function))
+    assert isinstance(context, (Contract, Function, Node))
+    if isinstance(context, Node):
+        func = context.function
+        context = func.contract if isinstance(func, FunctionContract) else func
     assert isinstance(only_unprotected, bool)
     if only_unprotected:
         return context.context[KEY_NON_SSA_UNPROTECTED]
@@ -203,18 +245,23 @@ def get_all_dependencies(
 
 def get_dependencies_ssa(
     variable: Variable_types,
-    context: Context_types,
+    context: Context_types_API,
     only_unprotected: bool = False,
 ) -> Set[Variable]:
     """
     Return the variables for which `variable` depends on (SSA version).
+    If Node is provided as context, the context will be the broader context, either the contract or the function,
+    depending on if the node is in a top level function or not
 
     :param variable: The target (must be SSA variable)
     :param context: Either a function (interprocedural) or a contract (inter transactional)
     :param only_unprotected: True if consider only protected functions
     :return: set(Variable)
     """
-    assert isinstance(context, (Contract, Function))
+    assert isinstance(context, (Contract, Function, Node))
+    if isinstance(context, Node):
+        func = context.function
+        context = func.contract if isinstance(func, FunctionContract) else func
     assert isinstance(only_unprotected, bool)
     if only_unprotected:
         return context.context[KEY_SSA_UNPROTECTED].get(variable, set())
@@ -222,16 +269,21 @@ def get_dependencies_ssa(
 
 
 def get_all_dependencies_ssa(
-    context: Context_types, only_unprotected: bool = False
+    context: Context_types_API, only_unprotected: bool = False
 ) -> Dict[Variable, Set[Variable]]:
     """
     Return the dictionary of dependencies.
+    If Node is provided as context, the context will be the broader context, either the contract or the function,
+    depending on if the node is in a top level function or not
 
     :param context: Either a function (interprocedural) or a contract (inter transactional)
     :param only_unprotected: True if consider only protected functions
     :return: Dict(Variable, set(Variable))
     """
-    assert isinstance(context, (Contract, Function))
+    assert isinstance(context, (Contract, Function, Node))
+    if isinstance(context, Node):
+        func = context.function
+        context = func.contract if isinstance(func, FunctionContract) else func
     assert isinstance(only_unprotected, bool)
     if only_unprotected:
         return context.context[KEY_SSA_UNPROTECTED]
diff --git a/slither/core/cfg/node.py b/slither/core/cfg/node.py
index 7643b19b7..82502f889 100644
--- a/slither/core/cfg/node.py
+++ b/slither/core/cfg/node.py
@@ -6,7 +6,7 @@ from typing import Optional, List, Set, Dict, Tuple, Union, TYPE_CHECKING
 
 from slither.all_exceptions import SlitherException
 from slither.core.children.child_function import ChildFunction
-from slither.core.declarations import Contract, Function
+from slither.core.declarations import Contract, Function, FunctionContract
 from slither.core.declarations.solidity_variables import (
     SolidityVariable,
     SolidityFunction,
@@ -33,6 +33,7 @@ from slither.slithir.operations import (
     Return,
     Operation,
 )
+from slither.slithir.utils.utils import RVALUE
 from slither.slithir.variables import (
     Constant,
     LocalIRVariable,
@@ -146,12 +147,12 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         self._node_id: int = node_id
 
         self._vars_written: List[Variable] = []
-        self._vars_read: List[Variable] = []
+        self._vars_read: List[Union[Variable, SolidityVariable]] = []
 
         self._ssa_vars_written: List["SlithIRVariable"] = []
         self._ssa_vars_read: List["SlithIRVariable"] = []
 
-        self._internal_calls: List["Function"] = []
+        self._internal_calls: List[Union["Function", "SolidityFunction"]] = []
         self._solidity_calls: List[SolidityFunction] = []
         self._high_level_calls: List["HighLevelCallType"] = []  # contains library calls
         self._library_calls: List["LibraryCallType"] = []
@@ -172,7 +173,9 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         self._local_vars_read: List[LocalVariable] = []
         self._local_vars_written: List[LocalVariable] = []
 
-        self._slithir_vars: Set["SlithIRVariable"] = set()  # non SSA
+        self._slithir_vars: Set[
+            Union["SlithIRVariable", ReferenceVariable, TemporaryVariable, TupleVariable]
+        ] = set()  # non SSA
 
         self._ssa_local_vars_read: List[LocalIRVariable] = []
         self._ssa_local_vars_written: List[LocalIRVariable] = []
@@ -213,7 +216,7 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         return self._node_type
 
     @type.setter
-    def type(self, new_type: NodeType):
+    def type(self, new_type: NodeType) -> None:
         self._node_type = new_type
 
     @property
@@ -232,7 +235,7 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
     ###################################################################################
 
     @property
-    def variables_read(self) -> List[Variable]:
+    def variables_read(self) -> List[Union[Variable, SolidityVariable]]:
         """
         list(Variable): Variables read (local/state/solidity)
         """
@@ -285,11 +288,13 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         return self._expression_vars_read
 
     @variables_read_as_expression.setter
-    def variables_read_as_expression(self, exprs: List[Expression]):
+    def variables_read_as_expression(self, exprs: List[Expression]) -> None:
         self._expression_vars_read = exprs
 
     @property
-    def slithir_variables(self) -> List["SlithIRVariable"]:
+    def slithir_variables(
+        self,
+    ) -> List[Union["SlithIRVariable", ReferenceVariable, TemporaryVariable, TupleVariable]]:
         return list(self._slithir_vars)
 
     @property
@@ -339,7 +344,7 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         return self._expression_vars_written
 
     @variables_written_as_expression.setter
-    def variables_written_as_expression(self, exprs: List[Expression]):
+    def variables_written_as_expression(self, exprs: List[Expression]) -> None:
         self._expression_vars_written = exprs
 
     # endregion
@@ -399,7 +404,7 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         return self._external_calls_as_expressions
 
     @external_calls_as_expressions.setter
-    def external_calls_as_expressions(self, exprs: List[Expression]):
+    def external_calls_as_expressions(self, exprs: List[Expression]) -> None:
         self._external_calls_as_expressions = exprs
 
     @property
@@ -410,7 +415,7 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         return self._internal_calls_as_expressions
 
     @internal_calls_as_expressions.setter
-    def internal_calls_as_expressions(self, exprs: List[Expression]):
+    def internal_calls_as_expressions(self, exprs: List[Expression]) -> None:
         self._internal_calls_as_expressions = exprs
 
     @property
@@ -418,10 +423,10 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         return list(self._expression_calls)
 
     @calls_as_expression.setter
-    def calls_as_expression(self, exprs: List[Expression]):
+    def calls_as_expression(self, exprs: List[Expression]) -> None:
         self._expression_calls = exprs
 
-    def can_reenter(self, callstack=None) -> bool:
+    def can_reenter(self, callstack: Optional[List[Union[Function, Variable]]] = None) -> bool:
         """
         Check if the node can re-enter
         Do not consider CREATE as potential re-enter, but check if the
@@ -567,7 +572,7 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         """
         self._fathers.append(father)
 
-    def set_fathers(self, fathers: List["Node"]):
+    def set_fathers(self, fathers: List["Node"]) -> None:
         """Set the father nodes
 
         Args:
@@ -663,20 +668,20 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         return self._irs_ssa
 
     @irs_ssa.setter
-    def irs_ssa(self, irs):
+    def irs_ssa(self, irs: List[Operation]) -> None:
         self._irs_ssa = irs
 
     def add_ssa_ir(self, ir: Operation) -> None:
         """
         Use to place phi operation
         """
-        ir.set_node(self)
+        ir.set_node(self)  # type: ignore
         self._irs_ssa.append(ir)
 
     def slithir_generation(self) -> None:
         if self.expression:
             expression = self.expression
-            self._irs = convert_expression(expression, self)
+            self._irs = convert_expression(expression, self)  # type:ignore
 
         self._find_read_write_call()
 
@@ -713,7 +718,7 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         return self._dominators
 
     @dominators.setter
-    def dominators(self, dom: Set["Node"]):
+    def dominators(self, dom: Set["Node"]) -> None:
         self._dominators = dom
 
     @property
@@ -725,7 +730,7 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         return self._immediate_dominator
 
     @immediate_dominator.setter
-    def immediate_dominator(self, idom: "Node"):
+    def immediate_dominator(self, idom: "Node") -> None:
         self._immediate_dominator = idom
 
     @property
@@ -737,7 +742,7 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         return self._dominance_frontier
 
     @dominance_frontier.setter
-    def dominance_frontier(self, doms: Set["Node"]):
+    def dominance_frontier(self, doms: Set["Node"]) -> None:
         """
         Returns:
             set(Node)
@@ -789,6 +794,7 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
 
     def add_phi_origin_local_variable(self, variable: LocalVariable, node: "Node") -> None:
         if variable.name not in self._phi_origins_local_variables:
+            assert variable.name
             self._phi_origins_local_variables[variable.name] = (variable, set())
         (v, nodes) = self._phi_origins_local_variables[variable.name]
         assert v == variable
@@ -827,7 +833,8 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
             if isinstance(ir, OperationWithLValue):
                 var = ir.lvalue
                 if var and self._is_valid_slithir_var(var):
-                    self._slithir_vars.add(var)
+                    # The type is checked by is_valid_slithir_var
+                    self._slithir_vars.add(var)  # type: ignore
 
             if not isinstance(ir, (Phi, Index, Member)):
                 self._vars_read += [v for v in ir.read if self._is_non_slithir_var(v)]
@@ -835,8 +842,9 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
                     if isinstance(var, ReferenceVariable):
                         self._vars_read.append(var.points_to_origin)
             elif isinstance(ir, (Member, Index)):
+                # TODO investigate types for member variable left
                 var = ir.variable_left if isinstance(ir, Member) else ir.variable_right
-                if self._is_non_slithir_var(var):
+                if var and self._is_non_slithir_var(var):
                     self._vars_read.append(var)
                 if isinstance(var, ReferenceVariable):
                     origin = var.points_to_origin
@@ -860,14 +868,21 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
                 self._internal_calls.append(ir.function)
             if isinstance(ir, LowLevelCall):
                 assert isinstance(ir.destination, (Variable, SolidityVariable))
-                self._low_level_calls.append((ir.destination, ir.function_name.value))
+                self._low_level_calls.append((ir.destination, str(ir.function_name.value)))
             elif isinstance(ir, HighLevelCall) and not isinstance(ir, LibraryCall):
+                # Todo investigate this if condition
+                # It does seem right to compare against a contract
+                # This might need a refactoring
                 if isinstance(ir.destination.type, Contract):
                     self._high_level_calls.append((ir.destination.type, ir.function))
                 elif ir.destination == SolidityVariable("this"):
-                    self._high_level_calls.append((self.function.contract, ir.function))
+                    func = self.function
+                    # Can't use this in a top level function
+                    assert isinstance(func, FunctionContract)
+                    self._high_level_calls.append((func.contract, ir.function))
                 else:
                     try:
+                        # Todo this part needs more tests and documentation
                         self._high_level_calls.append((ir.destination.type.type, ir.function))
                     except AttributeError as error:
                         #  pylint: disable=raise-missing-from
@@ -883,7 +898,9 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         self._vars_read = list(set(self._vars_read))
         self._state_vars_read = [v for v in self._vars_read if isinstance(v, StateVariable)]
         self._local_vars_read = [v for v in self._vars_read if isinstance(v, LocalVariable)]
-        self._solidity_vars_read = [v for v in self._vars_read if isinstance(v, SolidityVariable)]
+        self._solidity_vars_read = [
+            v_ for v_ in self._vars_read if isinstance(v_, SolidityVariable)
+        ]
         self._vars_written = list(set(self._vars_written))
         self._state_vars_written = [v for v in self._vars_written if isinstance(v, StateVariable)]
         self._local_vars_written = [v for v in self._vars_written if isinstance(v, LocalVariable)]
@@ -895,12 +912,15 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
 
     @staticmethod
     def _convert_ssa(v: Variable) -> Optional[Union[StateVariable, LocalVariable]]:
+        non_ssa_var: Optional[Union[StateVariable, LocalVariable]]
         if isinstance(v, StateIRVariable):
             contract = v.contract
+            assert v.name
             non_ssa_var = contract.get_state_variable_from_name(v.name)
             return non_ssa_var
         assert isinstance(v, LocalIRVariable)
         function = v.function
+        assert v.name
         non_ssa_var = function.get_local_variable_from_name(v.name)
         return non_ssa_var
 
@@ -921,10 +941,11 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
                             self._ssa_vars_read.append(origin)
 
             elif isinstance(ir, (Member, Index)):
-                if isinstance(ir.variable_right, (StateIRVariable, LocalIRVariable)):
-                    self._ssa_vars_read.append(ir.variable_right)
-                if isinstance(ir.variable_right, ReferenceVariable):
-                    origin = ir.variable_right.points_to_origin
+                variable_right: RVALUE = ir.variable_right
+                if isinstance(variable_right, (StateIRVariable, LocalIRVariable)):
+                    self._ssa_vars_read.append(variable_right)
+                if isinstance(variable_right, ReferenceVariable):
+                    origin = variable_right.points_to_origin
                     if isinstance(origin, (StateIRVariable, LocalIRVariable)):
                         self._ssa_vars_read.append(origin)
 
@@ -944,20 +965,20 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
         self._ssa_local_vars_read = [v for v in self._ssa_vars_read if isinstance(v, LocalVariable)]
         self._ssa_vars_written = list(set(self._ssa_vars_written))
         self._ssa_state_vars_written = [
-            v for v in self._ssa_vars_written if isinstance(v, StateVariable)
+            v for v in self._ssa_vars_written if v and isinstance(v, StateIRVariable)
         ]
         self._ssa_local_vars_written = [
-            v for v in self._ssa_vars_written if isinstance(v, LocalVariable)
+            v for v in self._ssa_vars_written if v and isinstance(v, LocalIRVariable)
         ]
 
         vars_read = [self._convert_ssa(x) for x in self._ssa_vars_read]
         vars_written = [self._convert_ssa(x) for x in self._ssa_vars_written]
 
-        self._vars_read += [v for v in vars_read if v not in self._vars_read]
+        self._vars_read += [v_ for v_ in vars_read if v_ and v_ not in self._vars_read]
         self._state_vars_read = [v for v in self._vars_read if isinstance(v, StateVariable)]
         self._local_vars_read = [v for v in self._vars_read if isinstance(v, LocalVariable)]
 
-        self._vars_written += [v for v in vars_written if v not in self._vars_written]
+        self._vars_written += [v_ for v_ in vars_written if v_ and v_ not in self._vars_written]
         self._state_vars_written = [v for v in self._vars_written if isinstance(v, StateVariable)]
         self._local_vars_written = [v for v in self._vars_written if isinstance(v, LocalVariable)]
 
@@ -974,7 +995,7 @@ class Node(SourceMapping, ChildFunction):  # pylint: disable=too-many-public-met
             additional_info += " " + str(self.expression)
         elif self.variable_declaration:
             additional_info += " " + str(self.variable_declaration)
-        txt = self._node_type.value + additional_info
+        txt = str(self._node_type.value) + additional_info
         return txt
 
 
diff --git a/slither/core/children/child_contract.py b/slither/core/children/child_contract.py
index 86f9dea53..2c93d9a51 100644
--- a/slither/core/children/child_contract.py
+++ b/slither/core/children/child_contract.py
@@ -1,4 +1,4 @@
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Optional
 
 from slither.core.source_mapping.source_mapping import SourceMapping
 
@@ -9,11 +9,14 @@ if TYPE_CHECKING:
 class ChildContract(SourceMapping):
     def __init__(self) -> None:
         super().__init__()
-        self._contract = None
+        # TODO remove all the setters for the child objects
+        # And make it a constructor arguement
+        # This will remove the optional
+        self._contract: Optional["Contract"] = None
 
     def set_contract(self, contract: "Contract") -> None:
         self._contract = contract
 
     @property
     def contract(self) -> "Contract":
-        return self._contract
+        return self._contract  # type: ignore
diff --git a/slither/core/children/child_event.py b/slither/core/children/child_event.py
index df91596e3..e9a2177c5 100644
--- a/slither/core/children/child_event.py
+++ b/slither/core/children/child_event.py
@@ -1,4 +1,4 @@
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Optional
 
 if TYPE_CHECKING:
     from slither.core.declarations import Event
@@ -7,11 +7,14 @@ if TYPE_CHECKING:
 class ChildEvent:
     def __init__(self) -> None:
         super().__init__()
-        self._event = None
+        # TODO remove all the setters for the child objects
+        # And make it a constructor arguement
+        # This will remove the optional
+        self._event: Optional["Event"] = None
 
-    def set_event(self, event: "Event"):
+    def set_event(self, event: "Event") -> None:
         self._event = event
 
     @property
     def event(self) -> "Event":
-        return self._event
+        return self._event  # type: ignore
diff --git a/slither/core/children/child_expression.py b/slither/core/children/child_expression.py
index 0064658c0..2294cf384 100644
--- a/slither/core/children/child_expression.py
+++ b/slither/core/children/child_expression.py
@@ -1,4 +1,4 @@
-from typing import TYPE_CHECKING, Union
+from typing import TYPE_CHECKING, Union, Optional
 
 if TYPE_CHECKING:
     from slither.core.expressions.expression import Expression
@@ -8,11 +8,16 @@ if TYPE_CHECKING:
 class ChildExpression:
     def __init__(self) -> None:
         super().__init__()
-        self._expression = None
+        # TODO remove all the setters for the child objects
+        # And make it a constructor arguement
+        # This will remove the optional
+        self._expression: Optional[Union["Expression", "Operation"]] = None
 
     def set_expression(self, expression: Union["Expression", "Operation"]) -> None:
+        # TODO investigate when this can be an operation?
+        # It was auto generated during an AST or detectors tests
         self._expression = expression
 
     @property
     def expression(self) -> Union["Expression", "Operation"]:
-        return self._expression
+        return self._expression  # type: ignore
diff --git a/slither/core/children/child_function.py b/slither/core/children/child_function.py
index 5367320ca..d79d12c10 100644
--- a/slither/core/children/child_function.py
+++ b/slither/core/children/child_function.py
@@ -1,4 +1,4 @@
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Optional
 
 if TYPE_CHECKING:
     from slither.core.declarations import Function
@@ -7,11 +7,14 @@ if TYPE_CHECKING:
 class ChildFunction:
     def __init__(self) -> None:
         super().__init__()
-        self._function = None
+        # TODO remove all the setters for the child objects
+        # And make it a constructor arguement
+        # This will remove the optional
+        self._function: Optional["Function"] = None
 
     def set_function(self, function: "Function") -> None:
         self._function = function
 
     @property
     def function(self) -> "Function":
-        return self._function
+        return self._function  # type: ignore
diff --git a/slither/core/children/child_inheritance.py b/slither/core/children/child_inheritance.py
index 30b32f6c1..1ff1a4967 100644
--- a/slither/core/children/child_inheritance.py
+++ b/slither/core/children/child_inheritance.py
@@ -1,4 +1,4 @@
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Optional
 
 if TYPE_CHECKING:
     from slither.core.declarations import Contract
@@ -7,11 +7,14 @@ if TYPE_CHECKING:
 class ChildInheritance:
     def __init__(self) -> None:
         super().__init__()
-        self._contract_declarer = None
+        # TODO remove all the setters for the child objects
+        # And make it a constructor arguement
+        # This will remove the optional
+        self._contract_declarer: Optional["Contract"] = None
 
     def set_contract_declarer(self, contract: "Contract") -> None:
         self._contract_declarer = contract
 
     @property
     def contract_declarer(self) -> "Contract":
-        return self._contract_declarer
+        return self._contract_declarer  # type: ignore
diff --git a/slither/core/children/child_node.py b/slither/core/children/child_node.py
index 8e6e1f0b5..998ec5ea4 100644
--- a/slither/core/children/child_node.py
+++ b/slither/core/children/child_node.py
@@ -1,4 +1,4 @@
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Optional
 
 if TYPE_CHECKING:
     from slither.core.compilation_unit import SlitherCompilationUnit
@@ -9,14 +9,17 @@ if TYPE_CHECKING:
 class ChildNode:
     def __init__(self) -> None:
         super().__init__()
-        self._node = None
+        # TODO remove all the setters for the child objects
+        # And make it a constructor arguement
+        # This will remove the optional
+        self._node: Optional["Node"] = None
 
     def set_node(self, node: "Node") -> None:
         self._node = node
 
     @property
     def node(self) -> "Node":
-        return self._node
+        return self._node  # type:ignore
 
     @property
     def function(self) -> "Function":
@@ -24,7 +27,7 @@ class ChildNode:
 
     @property
     def contract(self) -> "Contract":
-        return self.node.function.contract
+        return self.node.function.contract  # type: ignore
 
     @property
     def compilation_unit(self) -> "SlitherCompilationUnit":
diff --git a/slither/core/children/child_structure.py b/slither/core/children/child_structure.py
index abcb041c2..413d7f4df 100644
--- a/slither/core/children/child_structure.py
+++ b/slither/core/children/child_structure.py
@@ -1,4 +1,4 @@
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Optional
 
 if TYPE_CHECKING:
     from slither.core.declarations import Structure
@@ -7,11 +7,14 @@ if TYPE_CHECKING:
 class ChildStructure:
     def __init__(self) -> None:
         super().__init__()
-        self._structure = None
+        # TODO remove all the setters for the child objects
+        # And make it a constructor arguement
+        # This will remove the optional
+        self._structure: Optional["Structure"] = None
 
     def set_structure(self, structure: "Structure") -> None:
         self._structure = structure
 
     @property
     def structure(self) -> "Structure":
-        return self._structure
+        return self._structure  # type: ignore
diff --git a/slither/core/declarations/contract.py b/slither/core/declarations/contract.py
index 2d2d10b04..d3c016b4b 100644
--- a/slither/core/declarations/contract.py
+++ b/slither/core/declarations/contract.py
@@ -81,7 +81,7 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
 
         # The only str is "*"
         self._using_for: Dict[Union[str, Type], List[Type]] = {}
-        self._using_for_complete: Dict[Union[str, Type], List[Type]] = None
+        self._using_for_complete: Optional[Dict[Union[str, Type], List[Type]]] = None
         self._kind: Optional[str] = None
         self._is_interface: bool = False
         self._is_library: bool = False
@@ -275,7 +275,7 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
         Dict[Union[str, Type], List[Type]]: Dict of merged local using for directive with top level directive
         """
 
-        def _merge_using_for(uf1, uf2):
+        def _merge_using_for(uf1: Dict, uf2: Dict) -> Dict:
             result = {**uf1, **uf2}
             for key, value in result.items():
                 if key in uf1 and key in uf2:
@@ -524,14 +524,14 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
         """
         return list(self._functions.values())
 
-    def available_functions_as_dict(self) -> Dict[str, "FunctionContract"]:
+    def available_functions_as_dict(self) -> Dict[str, "Function"]:
         if self._available_functions_as_dict is None:
             self._available_functions_as_dict = {
                 f.full_name: f for f in self._functions.values() if not f.is_shadowed
             }
         return self._available_functions_as_dict
 
-    def add_function(self, func: "FunctionContract"):
+    def add_function(self, func: "FunctionContract") -> None:
         self._functions[func.canonical_name] = func
 
     def set_functions(self, functions: Dict[str, "FunctionContract"]) -> None:
@@ -699,7 +699,7 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
         list(Contract): Return the list of contracts derived from self
         """
         candidates = self.compilation_unit.contracts
-        return [c for c in candidates if self in c.inheritance]
+        return [c for c in candidates if self in c.inheritance]  # type: ignore
 
     # endregion
     ###################################################################################
@@ -855,7 +855,7 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
         """
         return next((e for e in self.enums if e.name == enum_name), None)
 
-    def get_enum_from_canonical_name(self, enum_name) -> Optional["Enum"]:
+    def get_enum_from_canonical_name(self, enum_name: str) -> Optional["Enum"]:
         """
             Return an enum from a canonical name
         Args:
@@ -956,7 +956,9 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
     ###################################################################################
     ###################################################################################
 
-    def get_summary(self, include_shadowed=True) -> Tuple[str, List[str], List[str], List, List]:
+    def get_summary(
+        self, include_shadowed: bool = True
+    ) -> Tuple[str, List[str], List[str], List, List]:
         """Return the function summary
 
         :param include_shadowed: boolean to indicate if shadowed functions should be included (default True)
@@ -1209,7 +1211,7 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
 
     @property
     def is_test(self) -> bool:
-        return is_test_contract(self) or self.is_truffle_migration
+        return is_test_contract(self) or self.is_truffle_migration  # type: ignore
 
     # endregion
     ###################################################################################
@@ -1219,7 +1221,7 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
     ###################################################################################
 
     def update_read_write_using_ssa(self) -> None:
-        for function in self.functions + self.modifiers:
+        for function in self.functions + list(self.modifiers):
             function.update_read_write_using_ssa()
 
     # endregion
@@ -1254,7 +1256,7 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
         return self._is_upgradeable
 
     @is_upgradeable.setter
-    def is_upgradeable(self, upgradeable: bool):
+    def is_upgradeable(self, upgradeable: bool) -> None:
         self._is_upgradeable = upgradeable
 
     @property
@@ -1283,7 +1285,7 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
         return self._is_upgradeable_proxy
 
     @is_upgradeable_proxy.setter
-    def is_upgradeable_proxy(self, upgradeable_proxy: bool):
+    def is_upgradeable_proxy(self, upgradeable_proxy: bool) -> None:
         self._is_upgradeable_proxy = upgradeable_proxy
 
     @property
@@ -1291,7 +1293,7 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
         return self._upgradeable_version
 
     @upgradeable_version.setter
-    def upgradeable_version(self, version_name: str):
+    def upgradeable_version(self, version_name: str) -> None:
         self._upgradeable_version = version_name
 
     # endregion
@@ -1310,7 +1312,7 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
         return self._is_incorrectly_parsed
 
     @is_incorrectly_constructed.setter
-    def is_incorrectly_constructed(self, incorrect: bool):
+    def is_incorrectly_constructed(self, incorrect: bool) -> None:
         self._is_incorrectly_parsed = incorrect
 
     def add_constructor_variables(self) -> None:
@@ -1322,8 +1324,8 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
 
                     constructor_variable = FunctionContract(self.compilation_unit)
                     constructor_variable.set_function_type(FunctionType.CONSTRUCTOR_VARIABLES)
-                    constructor_variable.set_contract(self)
-                    constructor_variable.set_contract_declarer(self)
+                    constructor_variable.set_contract(self)  # type: ignore
+                    constructor_variable.set_contract_declarer(self)  # type: ignore
                     constructor_variable.set_visibility("internal")
                     # For now, source mapping of the constructor variable is the whole contract
                     # Could be improved with a targeted source mapping
@@ -1354,8 +1356,8 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
                     constructor_variable.set_function_type(
                         FunctionType.CONSTRUCTOR_CONSTANT_VARIABLES
                     )
-                    constructor_variable.set_contract(self)
-                    constructor_variable.set_contract_declarer(self)
+                    constructor_variable.set_contract(self)  # type: ignore
+                    constructor_variable.set_contract_declarer(self)  # type: ignore
                     constructor_variable.set_visibility("internal")
                     # For now, source mapping of the constructor variable is the whole contract
                     # Could be improved with a targeted source mapping
@@ -1436,22 +1438,23 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
                 all_ssa_state_variables_instances[v.canonical_name] = new_var
                 self._initial_state_variables.append(new_var)
 
-        for func in self.functions + self.modifiers:
+        for func in self.functions + list(self.modifiers):
             func.generate_slithir_ssa(all_ssa_state_variables_instances)
 
     def fix_phi(self) -> None:
-        last_state_variables_instances = {}
-        initial_state_variables_instances = {}
+        last_state_variables_instances: Dict[str, List["StateVariable"]] = {}
+        initial_state_variables_instances: Dict[str, "StateVariable"] = {}
         for v in self._initial_state_variables:
             last_state_variables_instances[v.canonical_name] = []
             initial_state_variables_instances[v.canonical_name] = v
 
-        for func in self.functions + self.modifiers:
+        for func in self.functions + list(self.modifiers):
             result = func.get_last_ssa_state_variables_instances()
             for variable_name, instances in result.items():
+                # TODO: investigate the next operation
                 last_state_variables_instances[variable_name] += instances
 
-        for func in self.functions + self.modifiers:
+        for func in self.functions + list(self.modifiers):
             func.fix_phi(last_state_variables_instances, initial_state_variables_instances)
 
     # endregion
@@ -1461,7 +1464,7 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
     ###################################################################################
     ###################################################################################
 
-    def __eq__(self, other: SourceMapping) -> bool:
+    def __eq__(self, other: Any) -> bool:
         if isinstance(other, str):
             return other == self.name
         return NotImplemented
@@ -1475,6 +1478,6 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
         return self.name
 
     def __hash__(self) -> int:
-        return self._id
+        return self._id  # type:ignore
 
     # endregion
diff --git a/slither/core/declarations/custom_error.py b/slither/core/declarations/custom_error.py
index 5e851c8da..c566fccec 100644
--- a/slither/core/declarations/custom_error.py
+++ b/slither/core/declarations/custom_error.py
@@ -51,7 +51,7 @@ class CustomError(SourceMapping):
         return str(t)
 
     @property
-    def solidity_signature(self) -> Optional[str]:
+    def solidity_signature(self) -> str:
         """
         Return a signature following the Solidity Standard
         Contract and converted into address
@@ -63,7 +63,7 @@ class CustomError(SourceMapping):
         # (set_solidity_sig was not called before find_variable)
         if self._solidity_signature is None:
             raise ValueError("Custom Error not yet built")
-        return self._solidity_signature
+        return self._solidity_signature  # type: ignore
 
     def set_solidity_sig(self) -> None:
         """
diff --git a/slither/core/declarations/custom_error_contract.py b/slither/core/declarations/custom_error_contract.py
index a96f12057..d5b7b6a92 100644
--- a/slither/core/declarations/custom_error_contract.py
+++ b/slither/core/declarations/custom_error_contract.py
@@ -1,9 +1,14 @@
+from typing import TYPE_CHECKING
+
 from slither.core.children.child_contract import ChildContract
 from slither.core.declarations.custom_error import CustomError
 
+if TYPE_CHECKING:
+    from slither.core.declarations import Contract
+
 
 class CustomErrorContract(CustomError, ChildContract):
-    def is_declared_by(self, contract):
+    def is_declared_by(self, contract: "Contract") -> bool:
         """
         Check if the element is declared by the contract
         :param contract:
diff --git a/slither/core/declarations/custom_error_top_level.py b/slither/core/declarations/custom_error_top_level.py
index 29a9fd41a..64a6a8535 100644
--- a/slither/core/declarations/custom_error_top_level.py
+++ b/slither/core/declarations/custom_error_top_level.py
@@ -9,6 +9,6 @@ if TYPE_CHECKING:
 
 
 class CustomErrorTopLevel(CustomError, TopLevel):
-    def __init__(self, compilation_unit: "SlitherCompilationUnit", scope: "FileScope"):
+    def __init__(self, compilation_unit: "SlitherCompilationUnit", scope: "FileScope") -> None:
         super().__init__(compilation_unit)
         self.file_scope: "FileScope" = scope
diff --git a/slither/core/declarations/function.py b/slither/core/declarations/function.py
index c383fc99b..e77801961 100644
--- a/slither/core/declarations/function.py
+++ b/slither/core/declarations/function.py
@@ -47,7 +47,6 @@ if TYPE_CHECKING:
     from slither.core.compilation_unit import SlitherCompilationUnit
     from slither.core.scope.scope import FileScope
     from slither.slithir.variables.state_variable import StateIRVariable
-    from slither.core.declarations.function_contract import FunctionContract
 
 LOGGER = logging.getLogger("Function")
 ReacheableNode = namedtuple("ReacheableNode", ["node", "ir"])
@@ -298,7 +297,7 @@ class Function(SourceMapping, metaclass=ABCMeta):  # pylint: disable=too-many-pu
     def contains_assembly(self, c: bool):
         self._contains_assembly = c
 
-    def can_reenter(self, callstack: Optional[List["FunctionContract"]] = None) -> bool:
+    def can_reenter(self, callstack: Optional[List[Union["Function", "Variable"]]] = None) -> bool:
         """
         Check if the function can re-enter
         Follow internal calls.
@@ -1720,8 +1719,8 @@ class Function(SourceMapping, metaclass=ABCMeta):  # pylint: disable=too-many-pu
 
     def fix_phi(
         self,
-        last_state_variables_instances: Dict[str, List["StateIRVariable"]],
-        initial_state_variables_instances: Dict[str, "StateIRVariable"],
+        last_state_variables_instances: Dict[str, List["StateVariable"]],
+        initial_state_variables_instances: Dict[str, "StateVariable"],
     ) -> None:
         from slither.slithir.operations import InternalCall, PhiCallback
         from slither.slithir.variables import Constant, StateIRVariable
diff --git a/slither/core/declarations/solidity_variables.py b/slither/core/declarations/solidity_variables.py
index 9569cde93..f0e903d7b 100644
--- a/slither/core/declarations/solidity_variables.py
+++ b/slither/core/declarations/solidity_variables.py
@@ -82,7 +82,7 @@ SOLIDITY_FUNCTIONS: Dict[str, List[str]] = {
 }
 
 
-def solidity_function_signature(name):
+def solidity_function_signature(name: str) -> str:
     """
         Return the function signature (containing the return value)
         It is useful if a solidity function is used as a pointer
@@ -106,7 +106,7 @@ class SolidityVariable(SourceMapping):
         assert name in SOLIDITY_VARIABLES or name.endswith(("_slot", "_offset"))
 
     @property
-    def state_variable(self):
+    def state_variable(self) -> str:
         if self._name.endswith("_slot"):
             return self._name[:-5]
         if self._name.endswith("_offset"):
@@ -125,7 +125,7 @@ class SolidityVariable(SourceMapping):
     def __str__(self) -> str:
         return self._name
 
-    def __eq__(self, other: SourceMapping) -> bool:
+    def __eq__(self, other: Any) -> bool:
         return self.__class__ == other.__class__ and self.name == other.name
 
     def __hash__(self) -> int:
@@ -182,13 +182,13 @@ class SolidityFunction(SourceMapping):
         return self._return_type
 
     @return_type.setter
-    def return_type(self, r: List[Union[TypeInformation, ElementaryType]]):
+    def return_type(self, r: List[Union[TypeInformation, ElementaryType]]) -> None:
         self._return_type = r
 
     def __str__(self) -> str:
         return self._name
 
-    def __eq__(self, other: "SolidityFunction") -> bool:
+    def __eq__(self, other: Any) -> bool:
         return self.__class__ == other.__class__ and self.name == other.name
 
     def __hash__(self) -> int:
@@ -201,7 +201,7 @@ class SolidityCustomRevert(SolidityFunction):
         self._custom_error = custom_error
         self._return_type: List[Union[TypeInformation, ElementaryType]] = []
 
-    def __eq__(self, other: Union["SolidityCustomRevert", SolidityFunction]) -> bool:
+    def __eq__(self, other: Any) -> bool:
         return (
             self.__class__ == other.__class__
             and self.name == other.name
diff --git a/slither/core/dominators/utils.py b/slither/core/dominators/utils.py
index ca5c51282..4dd55749d 100644
--- a/slither/core/dominators/utils.py
+++ b/slither/core/dominators/utils.py
@@ -95,4 +95,5 @@ def compute_dominance_frontier(nodes: List["Node"]) -> None:
                     runner.dominance_frontier = runner.dominance_frontier.union({node})
                 while runner != node.immediate_dominator:
                     runner.dominance_frontier = runner.dominance_frontier.union({node})
+                    assert runner.immediate_dominator
                     runner = runner.immediate_dominator
diff --git a/slither/core/expressions/assignment_operation.py b/slither/core/expressions/assignment_operation.py
index 22aba57fb..7b7bc62d6 100644
--- a/slither/core/expressions/assignment_operation.py
+++ b/slither/core/expressions/assignment_operation.py
@@ -91,7 +91,7 @@ class AssignmentOperation(ExpressionTyped):
         super().__init__()
         left_expression.set_lvalue()
         self._expressions = [left_expression, right_expression]
-        self._type: Optional["AssignmentOperationType"] = expression_type
+        self._type: AssignmentOperationType = expression_type
         self._expression_return_type: Optional["Type"] = expression_return_type
 
     @property
diff --git a/slither/core/slither_core.py b/slither/core/slither_core.py
index e5f4e830a..ba2ec802d 100644
--- a/slither/core/slither_core.py
+++ b/slither/core/slither_core.py
@@ -482,8 +482,8 @@ class SlitherCore(Context):
     ###################################################################################
 
     @property
-    def crytic_compile(self) -> Optional[CryticCompile]:
-        return self._crytic_compile
+    def crytic_compile(self) -> CryticCompile:
+        return self._crytic_compile  # type: ignore
 
     # endregion
     ###################################################################################
diff --git a/slither/core/solidity_types/array_type.py b/slither/core/solidity_types/array_type.py
index 9a0b12c00..cdb8c10c7 100644
--- a/slither/core/solidity_types/array_type.py
+++ b/slither/core/solidity_types/array_type.py
@@ -4,11 +4,11 @@ from slither.core.expressions.expression import Expression
 from slither.core.solidity_types.type import Type
 from slither.visitors.expression.constants_folding import ConstantFolding
 from slither.core.expressions.literal import Literal
+from slither.core.solidity_types.elementary_type import ElementaryType
 
 if TYPE_CHECKING:
     from slither.core.expressions.binary_operation import BinaryOperation
     from slither.core.expressions.identifier import Identifier
-    from slither.core.solidity_types.elementary_type import ElementaryType
     from slither.core.solidity_types.function_type import FunctionType
     from slither.core.solidity_types.type_alias import TypeAliasTopLevel
 
@@ -22,7 +22,7 @@ class ArrayType(Type):
         assert isinstance(t, Type)
         if length:
             if isinstance(length, int):
-                length = Literal(length, "uint256")
+                length = Literal(length, ElementaryType("uint256"))
             assert isinstance(length, Expression)
         super().__init__()
         self._type: Type = t
diff --git a/slither/core/solidity_types/elementary_type.py b/slither/core/solidity_types/elementary_type.py
index ec2b0ef04..a9f45c8d8 100644
--- a/slither/core/solidity_types/elementary_type.py
+++ b/slither/core/solidity_types/elementary_type.py
@@ -1,5 +1,5 @@
 import itertools
-from typing import Tuple
+from typing import Tuple, Optional, Any
 
 from slither.core.solidity_types.type import Type
 
@@ -176,7 +176,7 @@ class ElementaryType(Type):
         return self.type
 
     @property
-    def size(self) -> int:
+    def size(self) -> Optional[int]:
         """
             Return the size in bits
             Return None if the size is not known
@@ -219,7 +219,7 @@ class ElementaryType(Type):
     def __str__(self) -> str:
         return self._type
 
-    def __eq__(self, other) -> bool:
+    def __eq__(self, other: Any) -> bool:
         if not isinstance(other, ElementaryType):
             return False
         return self.type == other.type
diff --git a/slither/core/solidity_types/mapping_type.py b/slither/core/solidity_types/mapping_type.py
index a8acb4d9c..9741569ed 100644
--- a/slither/core/solidity_types/mapping_type.py
+++ b/slither/core/solidity_types/mapping_type.py
@@ -1,4 +1,4 @@
-from typing import Union, Tuple, TYPE_CHECKING
+from typing import Union, Tuple, TYPE_CHECKING, Any
 
 from slither.core.solidity_types.type import Type
 
@@ -38,7 +38,7 @@ class MappingType(Type):
     def __str__(self) -> str:
         return f"mapping({str(self._from)} => {str(self._to)})"
 
-    def __eq__(self, other):
+    def __eq__(self, other: Any) -> bool:
         if not isinstance(other, MappingType):
             return False
         return self.type_from == other.type_from and self.type_to == other.type_to
diff --git a/slither/core/solidity_types/type_alias.py b/slither/core/solidity_types/type_alias.py
index 5b9ea0a37..1da2d4182 100644
--- a/slither/core/solidity_types/type_alias.py
+++ b/slither/core/solidity_types/type_alias.py
@@ -40,7 +40,7 @@ class TypeAlias(Type):
 
 
 class TypeAliasTopLevel(TypeAlias, TopLevel):
-    def __init__(self, underlying_type: Type, name: str, scope: "FileScope") -> None:
+    def __init__(self, underlying_type: ElementaryType, name: str, scope: "FileScope") -> None:
         super().__init__(underlying_type, name)
         self.file_scope: "FileScope" = scope
 
@@ -49,7 +49,7 @@ class TypeAliasTopLevel(TypeAlias, TopLevel):
 
 
 class TypeAliasContract(TypeAlias, ChildContract):
-    def __init__(self, underlying_type: Type, name: str, contract: "Contract") -> None:
+    def __init__(self, underlying_type: ElementaryType, name: str, contract: "Contract") -> None:
         super().__init__(underlying_type, name)
         self._contract: "Contract" = contract
 
diff --git a/slither/core/solidity_types/type_information.py b/slither/core/solidity_types/type_information.py
index 2af0b097a..9cef9352c 100644
--- a/slither/core/solidity_types/type_information.py
+++ b/slither/core/solidity_types/type_information.py
@@ -1,4 +1,4 @@
-from typing import Union, TYPE_CHECKING, Tuple
+from typing import Union, TYPE_CHECKING, Tuple, Any
 
 from slither.core.solidity_types import ElementaryType
 from slither.core.solidity_types.type import Type
@@ -40,10 +40,10 @@ class TypeInformation(Type):
     def is_dynamic(self) -> bool:
         raise NotImplementedError
 
-    def __str__(self):
+    def __str__(self) -> str:
         return f"type({self.type.name})"
 
-    def __eq__(self, other):
+    def __eq__(self, other: Any) -> bool:
         if not isinstance(other, TypeInformation):
             return False
         return self.type == other.type
diff --git a/slither/core/source_mapping/source_mapping.py b/slither/core/source_mapping/source_mapping.py
index a0fcf354a..4c8742b22 100644
--- a/slither/core/source_mapping/source_mapping.py
+++ b/slither/core/source_mapping/source_mapping.py
@@ -1,6 +1,6 @@
 import re
 from abc import ABCMeta
-from typing import Dict, Union, List, Tuple, TYPE_CHECKING, Optional
+from typing import Dict, Union, List, Tuple, TYPE_CHECKING, Optional, Any
 
 from Crypto.Hash import SHA1
 from crytic_compile.utils.naming import Filename
@@ -102,10 +102,10 @@ class Source:
         filename_short: str = self.filename.short if self.filename.short else ""
         return f"{filename_short}{lines}"
 
-    def __hash__(self):
+    def __hash__(self) -> int:
         return hash(str(self))
 
-    def __eq__(self, other):
+    def __eq__(self, other: Any) -> bool:
         if not isinstance(other, type(self)):
             return NotImplemented
         return (
diff --git a/slither/core/variables/event_variable.py b/slither/core/variables/event_variable.py
index f3ad60d0b..e191433dc 100644
--- a/slither/core/variables/event_variable.py
+++ b/slither/core/variables/event_variable.py
@@ -16,5 +16,5 @@ class EventVariable(ChildEvent, Variable):
         return self._indexed
 
     @indexed.setter
-    def indexed(self, is_indexed: bool):
+    def indexed(self, is_indexed: bool) -> bool:
         self._indexed = is_indexed
diff --git a/slither/core/variables/variable.py b/slither/core/variables/variable.py
index 8607a8921..c775e7c98 100644
--- a/slither/core/variables/variable.py
+++ b/slither/core/variables/variable.py
@@ -55,7 +55,7 @@ class Variable(SourceMapping):
         return self._initialized
 
     @initialized.setter
-    def initialized(self, is_init: bool):
+    def initialized(self, is_init: bool) -> None:
         self._initialized = is_init
 
     @property
@@ -73,7 +73,7 @@ class Variable(SourceMapping):
         return self._name
 
     @name.setter
-    def name(self, name):
+    def name(self, name: str) -> None:
         self._name = name
 
     @property
@@ -89,7 +89,7 @@ class Variable(SourceMapping):
         return self._is_constant
 
     @is_constant.setter
-    def is_constant(self, is_cst: bool):
+    def is_constant(self, is_cst: bool) -> None:
         self._is_constant = is_cst
 
     @property
diff --git a/slither/detectors/abstract_detector.py b/slither/detectors/abstract_detector.py
index 8e2dd490d..59f8ca3a0 100644
--- a/slither/detectors/abstract_detector.py
+++ b/slither/detectors/abstract_detector.py
@@ -59,6 +59,8 @@ ALL_SOLC_VERSIONS_06 = make_solc_versions(6, 0, 12)
 ALL_SOLC_VERSIONS_07 = make_solc_versions(7, 0, 6)
 # No VERSIONS_08 as it is still in dev
 
+DETECTOR_INFO = Union[str, List[Union[str, SupportedOutput]]]
+
 
 class AbstractDetector(metaclass=abc.ABCMeta):
     ARGUMENT = ""  # run the detector with slither.py --ARGUMENT
@@ -251,7 +253,7 @@ class AbstractDetector(metaclass=abc.ABCMeta):
 
     def generate_result(
         self,
-        info: Union[str, List[Union[str, SupportedOutput]]],
+        info: DETECTOR_INFO,
         additional_fields: Optional[Dict] = None,
     ) -> Output:
         output = Output(
diff --git a/slither/detectors/assembly/shift_parameter_mixup.py b/slither/detectors/assembly/shift_parameter_mixup.py
index 31dad2371..a4169499a 100644
--- a/slither/detectors/assembly/shift_parameter_mixup.py
+++ b/slither/detectors/assembly/shift_parameter_mixup.py
@@ -1,5 +1,9 @@
 from typing import List
-from slither.detectors.abstract_detector import AbstractDetector, DetectorClassification
+from slither.detectors.abstract_detector import (
+    AbstractDetector,
+    DetectorClassification,
+    DETECTOR_INFO,
+)
 from slither.slithir.operations import Binary, BinaryType
 from slither.slithir.variables import Constant
 from slither.core.declarations.function_contract import FunctionContract
@@ -49,7 +53,12 @@ The shift statement will right-shift the constant 8 by `a` bits"""
                     BinaryType.RIGHT_SHIFT,
                 ]:
                     if isinstance(ir.variable_left, Constant):
-                        info = [f, " contains an incorrect shift operation: ", node, "\n"]
+                        info: DETECTOR_INFO = [
+                            f,
+                            " contains an incorrect shift operation: ",
+                            node,
+                            "\n",
+                        ]
                         json = self.generate_result(info)
 
                         results.append(json)
diff --git a/slither/detectors/attributes/const_functions_asm.py b/slither/detectors/attributes/const_functions_asm.py
index e3a938361..6de5062d8 100644
--- a/slither/detectors/attributes/const_functions_asm.py
+++ b/slither/detectors/attributes/const_functions_asm.py
@@ -7,6 +7,7 @@ from slither.detectors.abstract_detector import (
     AbstractDetector,
     DetectorClassification,
     ALL_SOLC_VERSIONS_04,
+    DETECTOR_INFO,
 )
 from slither.formatters.attributes.const_functions import custom_format
 from slither.utils.output import Output
@@ -73,7 +74,10 @@ All the calls to `get` revert, breaking Bob's smart contract execution."""
                     if f.contains_assembly:
                         attr = "view" if f.view else "pure"
 
-                        info = [f, f" is declared {attr} but contains assembly code\n"]
+                        info: DETECTOR_INFO = [
+                            f,
+                            f" is declared {attr} but contains assembly code\n",
+                        ]
                         res = self.generate_result(info, {"contains_assembly": True})
 
                         results.append(res)
diff --git a/slither/detectors/compiler_bugs/array_by_reference.py b/slither/detectors/compiler_bugs/array_by_reference.py
index 83ed69b9b..fffe93847 100644
--- a/slither/detectors/compiler_bugs/array_by_reference.py
+++ b/slither/detectors/compiler_bugs/array_by_reference.py
@@ -105,7 +105,12 @@ As a result, Bob's usage of the contract is incorrect."""
         write to the array unsuccessfully.
         """
         # Define our resulting array.
-        results = []
+        results: List[
+            Union[
+                Tuple[Node, StateVariable, FunctionContract],
+                Tuple[Node, LocalVariable, FunctionContract],
+            ]
+        ] = []
 
         # Verify we have functions in our list to check for.
         if not array_modifying_funcs:
diff --git a/slither/detectors/erc/erc20/arbitrary_send_erc20.py b/slither/detectors/erc/erc20/arbitrary_send_erc20.py
index 17b1fba30..f06005459 100644
--- a/slither/detectors/erc/erc20/arbitrary_send_erc20.py
+++ b/slither/detectors/erc/erc20/arbitrary_send_erc20.py
@@ -61,12 +61,12 @@ class ArbitrarySendErc20:
                         is_dependent(
                             ir.arguments[0],
                             SolidityVariableComposed("msg.sender"),
-                            node.function.contract,
+                            node,
                         )
                         or is_dependent(
                             ir.arguments[0],
                             SolidityVariable("this"),
-                            node.function.contract,
+                            node,
                         )
                     )
                 ):
@@ -79,12 +79,12 @@ class ArbitrarySendErc20:
                         is_dependent(
                             ir.arguments[1],
                             SolidityVariableComposed("msg.sender"),
-                            node.function.contract,
+                            node,
                         )
                         or is_dependent(
                             ir.arguments[1],
                             SolidityVariable("this"),
-                            node.function.contract,
+                            node,
                         )
                     )
                 ):
diff --git a/slither/detectors/erc/erc20/arbitrary_send_erc20_no_permit.py b/slither/detectors/erc/erc20/arbitrary_send_erc20_no_permit.py
index f43b6302e..351f1dcfa 100644
--- a/slither/detectors/erc/erc20/arbitrary_send_erc20_no_permit.py
+++ b/slither/detectors/erc/erc20/arbitrary_send_erc20_no_permit.py
@@ -1,5 +1,9 @@
 from typing import List
-from slither.detectors.abstract_detector import AbstractDetector, DetectorClassification
+from slither.detectors.abstract_detector import (
+    AbstractDetector,
+    DetectorClassification,
+    DETECTOR_INFO,
+)
 from slither.utils.output import Output
 from .arbitrary_send_erc20 import ArbitrarySendErc20
 
@@ -38,7 +42,7 @@ Use `msg.sender` as `from` in transferFrom.
         arbitrary_sends.detect()
         for node in arbitrary_sends.no_permit_results:
             func = node.function
-            info = [func, " uses arbitrary from in transferFrom: ", node, "\n"]
+            info: DETECTOR_INFO = [func, " uses arbitrary from in transferFrom: ", node, "\n"]
             res = self.generate_result(info)
             results.append(res)
 
diff --git a/slither/detectors/erc/erc20/arbitrary_send_erc20_permit.py b/slither/detectors/erc/erc20/arbitrary_send_erc20_permit.py
index 1d311c442..ca4c4a793 100644
--- a/slither/detectors/erc/erc20/arbitrary_send_erc20_permit.py
+++ b/slither/detectors/erc/erc20/arbitrary_send_erc20_permit.py
@@ -1,5 +1,9 @@
 from typing import List
-from slither.detectors.abstract_detector import AbstractDetector, DetectorClassification
+from slither.detectors.abstract_detector import (
+    AbstractDetector,
+    DetectorClassification,
+    DETECTOR_INFO,
+)
 from slither.utils.output import Output
 from .arbitrary_send_erc20 import ArbitrarySendErc20
 
@@ -41,7 +45,7 @@ Ensure that the underlying ERC20 token correctly implements a permit function.
         arbitrary_sends.detect()
         for node in arbitrary_sends.permit_results:
             func = node.function
-            info = [
+            info: DETECTOR_INFO = [
                 func,
                 " uses arbitrary from in transferFrom in combination with permit: ",
                 node,
diff --git a/slither/detectors/functions/arbitrary_send_eth.py b/slither/detectors/functions/arbitrary_send_eth.py
index 390b1f2ab..e0112c6e1 100644
--- a/slither/detectors/functions/arbitrary_send_eth.py
+++ b/slither/detectors/functions/arbitrary_send_eth.py
@@ -39,6 +39,10 @@ def arbitrary_send(func: Function) -> Union[bool, List[Node]]:
 
     ret: List[Node] = []
     for node in func.nodes:
+        func = node.function
+        deps_target: Union[Contract, Function] = (
+            func.contract if isinstance(func, FunctionContract) else func
+        )
         for ir in node.irs:
             if isinstance(ir, SolidityCall):
                 if ir.function == SolidityFunction("ecrecover(bytes32,uint8,bytes32,bytes32)"):
@@ -49,7 +53,7 @@ def arbitrary_send(func: Function) -> Union[bool, List[Node]]:
                 if is_dependent(
                     ir.variable_right,
                     SolidityVariableComposed("msg.sender"),
-                    func.contract,
+                    deps_target,
                 ):
                     return False
             if isinstance(ir, (HighLevelCall, LowLevelCall, Transfer, Send)):
@@ -64,11 +68,11 @@ def arbitrary_send(func: Function) -> Union[bool, List[Node]]:
                 if is_dependent(
                     ir.call_value,
                     SolidityVariableComposed("msg.value"),
-                    func.contract,
+                    node,
                 ):
                     continue
 
-                if is_tainted(ir.destination, func.contract):
+                if is_tainted(ir.destination, node):
                     ret.append(node)
 
     return ret
diff --git a/slither/detectors/statements/array_length_assignment.py b/slither/detectors/statements/array_length_assignment.py
index 51302a2c9..f4ae01b88 100644
--- a/slither/detectors/statements/array_length_assignment.py
+++ b/slither/detectors/statements/array_length_assignment.py
@@ -7,6 +7,7 @@ from slither.detectors.abstract_detector import (
     DetectorClassification,
     ALL_SOLC_VERSIONS_04,
     ALL_SOLC_VERSIONS_05,
+    DETECTOR_INFO,
 )
 from slither.core.cfg.node import Node, NodeType
 from slither.slithir.operations import Assignment, Length
@@ -120,7 +121,7 @@ Otherwise, thoroughly review the contract to ensure a user-controlled variable c
         for contract in self.contracts:
             array_length_assignments = detect_array_length_assignment(contract)
             if array_length_assignments:
-                contract_info = [
+                contract_info: DETECTOR_INFO = [
                     contract,
                     " contract sets array length with a user-controlled value:\n",
                 ]
diff --git a/slither/detectors/statements/assembly.py b/slither/detectors/statements/assembly.py
index 2c0c49f09..25b5d8034 100644
--- a/slither/detectors/statements/assembly.py
+++ b/slither/detectors/statements/assembly.py
@@ -6,7 +6,11 @@ from typing import List, Tuple
 from slither.core.cfg.node import Node, NodeType
 from slither.core.declarations.contract import Contract
 from slither.core.declarations.function_contract import FunctionContract
-from slither.detectors.abstract_detector import AbstractDetector, DetectorClassification
+from slither.detectors.abstract_detector import (
+    AbstractDetector,
+    DetectorClassification,
+    DETECTOR_INFO,
+)
 from slither.utils.output import Output
 
 
@@ -52,7 +56,7 @@ class Assembly(AbstractDetector):
         for c in self.contracts:
             values = self.detect_assembly(c)
             for func, nodes in values:
-                info = [func, " uses assembly\n"]
+                info: DETECTOR_INFO = [func, " uses assembly\n"]
 
                 # sort the nodes to get deterministic results
                 nodes.sort(key=lambda x: x.node_id)
diff --git a/slither/slithir/operations/call.py b/slither/slithir/operations/call.py
index 07304fa99..37a2fe0b3 100644
--- a/slither/slithir/operations/call.py
+++ b/slither/slithir/operations/call.py
@@ -1,5 +1,7 @@
-from typing import Optional, List
+from typing import Optional, List, Union
 
+from slither.core.declarations import Function
+from slither.core.variables import Variable
 from slither.slithir.operations.operation import Operation
 
 
@@ -16,7 +18,8 @@ class Call(Operation):
     def arguments(self, v):
         self._arguments = v
 
-    def can_reenter(self, _callstack: Optional[List] = None) -> bool:  # pylint: disable=no-self-use
+    # pylint: disable=no-self-use
+    def can_reenter(self, _callstack: Optional[List[Union[Function, Variable]]] = None) -> bool:
         """
         Must be called after slithIR analysis pass
         :return: bool
diff --git a/slither/slithir/operations/high_level_call.py b/slither/slithir/operations/high_level_call.py
index 93fb73bd4..d707e11b3 100644
--- a/slither/slithir/operations/high_level_call.py
+++ b/slither/slithir/operations/high_level_call.py
@@ -1,5 +1,6 @@
 from typing import List, Optional, Union
 
+from slither.core.declarations import Contract
 from slither.slithir.operations.call import Call
 from slither.slithir.operations.lvalue import OperationWithLValue
 from slither.core.variables.variable import Variable
@@ -32,7 +33,8 @@ class HighLevelCall(Call, OperationWithLValue):
         assert is_valid_lvalue(result) or result is None
         self._check_destination(destination)
         super().__init__()
-        self._destination = destination
+        # Contract is only possible for library call, which inherits from highlevelcall
+        self._destination: Union[Variable, SolidityVariable, Contract] = destination  # type: ignore
         self._function_name = function_name
         self._nbr_arguments = nbr_arguments
         self._type_call = type_call
@@ -44,8 +46,9 @@ class HighLevelCall(Call, OperationWithLValue):
         self._call_gas = None
 
     # Development function, to be removed once the code is stable
-    # It is ovveride by LbraryCall
-    def _check_destination(self, destination: SourceMapping) -> None:  # pylint: disable=no-self-use
+    # It is overridden by LibraryCall
+    # pylint: disable=no-self-use
+    def _check_destination(self, destination: Union[Variable, SolidityVariable, Contract]) -> None:
         assert isinstance(destination, (Variable, SolidityVariable))
 
     @property
@@ -79,7 +82,14 @@ class HighLevelCall(Call, OperationWithLValue):
         return [x for x in all_read if x] + [self.destination]
 
     @property
-    def destination(self) -> SourceMapping:
+    def destination(self) -> Union[Variable, SolidityVariable, Contract]:
+        """
+        Return a variable or a solidityVariable
+        Contract is only possible for LibraryCall
+
+        Returns:
+
+        """
         return self._destination
 
     @property
@@ -116,7 +126,7 @@ class HighLevelCall(Call, OperationWithLValue):
                 return True
         return False
 
-    def can_reenter(self, callstack: None = None) -> bool:
+    def can_reenter(self, callstack: Optional[List[Union[Function, Variable]]] = None) -> bool:
         """
         Must be called after slithIR analysis pass
         For Solidity > 0.5, filter access to public variables and constant/pure/view
diff --git a/slither/slithir/operations/index.py b/slither/slithir/operations/index.py
index ade84fe1d..77daa9462 100644
--- a/slither/slithir/operations/index.py
+++ b/slither/slithir/operations/index.py
@@ -1,20 +1,20 @@
 from typing import List, Union
+
 from slither.core.declarations import SolidityVariableComposed
-from slither.slithir.operations.lvalue import OperationWithLValue
-from slither.slithir.utils.utils import is_valid_lvalue, is_valid_rvalue
-from slither.slithir.variables.reference import ReferenceVariable
 from slither.core.solidity_types.elementary_type import ElementaryType
 from slither.core.source_mapping.source_mapping import SourceMapping
 from slither.core.variables.variable import Variable
-from slither.slithir.variables.reference_ssa import ReferenceVariableSSA
+from slither.slithir.operations.lvalue import OperationWithLValue
+from slither.slithir.utils.utils import is_valid_lvalue, is_valid_rvalue, RVALUE, LVALUE
+from slither.slithir.variables.reference import ReferenceVariable
 
 
 class Index(OperationWithLValue):
     def __init__(
         self,
-        result: Union[ReferenceVariable, ReferenceVariableSSA],
+        result: ReferenceVariable,
         left_variable: Variable,
-        right_variable: SourceMapping,
+        right_variable: RVALUE,
         index_type: Union[ElementaryType, str],
     ) -> None:
         super().__init__()
@@ -25,23 +25,23 @@ class Index(OperationWithLValue):
         assert isinstance(result, ReferenceVariable)
         self._variables = [left_variable, right_variable]
         self._type = index_type
-        self._lvalue = result
+        self._lvalue: ReferenceVariable = result
 
     @property
     def read(self) -> List[SourceMapping]:
         return list(self.variables)
 
     @property
-    def variables(self) -> List[SourceMapping]:
-        return self._variables
+    def variables(self) -> List[Union[LVALUE, RVALUE, SolidityVariableComposed]]:
+        return self._variables  # type: ignore
 
     @property
-    def variable_left(self) -> Variable:
-        return self._variables[0]
+    def variable_left(self) -> Union[LVALUE, SolidityVariableComposed]:
+        return self._variables[0]  # type: ignore
 
     @property
-    def variable_right(self) -> SourceMapping:
-        return self._variables[1]
+    def variable_right(self) -> RVALUE:
+        return self._variables[1]  # type: ignore
 
     @property
     def index_type(self) -> Union[ElementaryType, str]:
diff --git a/slither/slithir/operations/library_call.py b/slither/slithir/operations/library_call.py
index ebe9bf5ef..1b7f4e8a6 100644
--- a/slither/slithir/operations/library_call.py
+++ b/slither/slithir/operations/library_call.py
@@ -1,4 +1,7 @@
-from slither.core.declarations import Function
+from typing import Union, Optional, List
+
+from slither.core.declarations import Function, SolidityVariable
+from slither.core.variables import Variable
 from slither.slithir.operations.high_level_call import HighLevelCall
 from slither.core.declarations.contract import Contract
 
@@ -9,10 +12,10 @@ class LibraryCall(HighLevelCall):
     """
 
     # Development function, to be removed once the code is stable
-    def _check_destination(self, destination: Contract) -> None:
+    def _check_destination(self, destination: Union[Variable, SolidityVariable, Contract]) -> None:
         assert isinstance(destination, Contract)
 
-    def can_reenter(self, callstack: None = None) -> bool:
+    def can_reenter(self, callstack: Optional[List[Union[Function, Variable]]] = None) -> bool:
         """
         Must be called after slithIR analysis pass
         :return: bool
@@ -20,11 +23,11 @@ class LibraryCall(HighLevelCall):
         if self.is_static_call():
             return False
         # In case of recursion, return False
-        callstack = [] if callstack is None else callstack
-        if self.function in callstack:
+        callstack_local = [] if callstack is None else callstack
+        if self.function in callstack_local:
             return False
-        callstack = callstack + [self.function]
-        return self.function.can_reenter(callstack)
+        callstack_local = callstack_local + [self.function]
+        return self.function.can_reenter(callstack_local)
 
     def __str__(self):
         gas = ""
diff --git a/slither/slithir/operations/low_level_call.py b/slither/slithir/operations/low_level_call.py
index 7e8c278b8..eac779d27 100644
--- a/slither/slithir/operations/low_level_call.py
+++ b/slither/slithir/operations/low_level_call.py
@@ -1,4 +1,6 @@
-from typing import List, Union
+from typing import List, Union, Optional
+
+from slither.core.declarations import Function
 from slither.slithir.operations.call import Call
 from slither.slithir.operations.lvalue import OperationWithLValue
 from slither.core.variables.variable import Variable
@@ -74,7 +76,7 @@ class LowLevelCall(Call, OperationWithLValue):  # pylint: disable=too-many-insta
         # remove None
         return self._unroll([x for x in all_read if x])
 
-    def can_reenter(self, _callstack: None = None) -> bool:
+    def can_reenter(self, _callstack: Optional[List[Union[Function, Variable]]] = None) -> bool:
         """
         Must be called after slithIR analysis pass
         :return: bool
diff --git a/slither/slithir/operations/lvalue.py b/slither/slithir/operations/lvalue.py
index d9b800c92..b983d1c5d 100644
--- a/slither/slithir/operations/lvalue.py
+++ b/slither/slithir/operations/lvalue.py
@@ -1,4 +1,6 @@
-from typing import Any, List
+from typing import Any, List, Optional
+
+from slither.core.variables import Variable
 from slither.slithir.operations.operation import Operation
 
 
@@ -10,16 +12,16 @@ class OperationWithLValue(Operation):
     def __init__(self) -> None:
         super().__init__()
 
-        self._lvalue = None
+        self._lvalue: Optional[Variable] = None
 
     @property
-    def lvalue(self):
+    def lvalue(self) -> Optional[Variable]:
         return self._lvalue
 
-    @property
-    def used(self) -> List[Any]:
-        return self.read + [self.lvalue]
-
     @lvalue.setter
-    def lvalue(self, lvalue):
+    def lvalue(self, lvalue: Variable) -> None:
         self._lvalue = lvalue
+
+    @property
+    def used(self) -> List[Optional[Any]]:
+        return self.read + [self.lvalue]
diff --git a/slither/slithir/operations/member.py b/slither/slithir/operations/member.py
index 9a561ea87..0942813cf 100644
--- a/slither/slithir/operations/member.py
+++ b/slither/slithir/operations/member.py
@@ -5,7 +5,7 @@ from slither.core.declarations.enum import Enum
 from slither.core.declarations.solidity_import_placeholder import SolidityImportPlaceHolder
 from slither.core.solidity_types import ElementaryType
 from slither.slithir.operations.lvalue import OperationWithLValue
-from slither.slithir.utils.utils import is_valid_rvalue
+from slither.slithir.utils.utils import is_valid_rvalue, RVALUE
 from slither.slithir.variables.constant import Constant
 from slither.slithir.variables.reference import ReferenceVariable
 from slither.core.source_mapping.source_mapping import SourceMapping
@@ -39,7 +39,9 @@ class Member(OperationWithLValue):
         assert isinstance(variable_right, Constant)
         assert isinstance(result, ReferenceVariable)
         super().__init__()
-        self._variable_left = variable_left
+        self._variable_left: Union[
+            RVALUE, Contract, Enum, Function, CustomError, SolidityImportPlaceHolder, ElementaryType
+        ] = variable_left
         self._variable_right = variable_right
         self._lvalue = result
         self._gas = None
@@ -50,7 +52,11 @@ class Member(OperationWithLValue):
         return [self.variable_left, self.variable_right]
 
     @property
-    def variable_left(self) -> SourceMapping:
+    def variable_left(
+        self,
+    ) -> Union[
+        RVALUE, Contract, Enum, Function, CustomError, SolidityImportPlaceHolder, ElementaryType
+    ]:
         return self._variable_left
 
     @property
diff --git a/slither/slithir/operations/new_contract.py b/slither/slithir/operations/new_contract.py
index 879d12df6..8d3c949df 100644
--- a/slither/slithir/operations/new_contract.py
+++ b/slither/slithir/operations/new_contract.py
@@ -1,11 +1,13 @@
 from typing import Optional, Any, List, Union
+
+from slither.core.declarations import Function
+from slither.core.declarations.contract import Contract
+from slither.core.variables import Variable
 from slither.slithir.operations import Call, OperationWithLValue
 from slither.slithir.utils.utils import is_valid_lvalue
 from slither.slithir.variables.constant import Constant
-from slither.core.declarations.contract import Contract
 from slither.slithir.variables.temporary import TemporaryVariable
 from slither.slithir.variables.temporary_ssa import TemporaryVariableSSA
-from slither.core.declarations.function_contract import FunctionContract
 
 
 class NewContract(Call, OperationWithLValue):  # pylint: disable=too-many-instance-attributes
@@ -58,6 +60,7 @@ class NewContract(Call, OperationWithLValue):  # pylint: disable=too-many-instan
     def contract_created(self) -> Contract:
         contract_name = self.contract_name
         contract_instance = self.node.file_scope.get_contract_from_name(contract_name)
+        assert contract_instance
         return contract_instance
 
     ###################################################################################
@@ -66,7 +69,7 @@ class NewContract(Call, OperationWithLValue):  # pylint: disable=too-many-instan
     ###################################################################################
     ###################################################################################
 
-    def can_reenter(self, callstack: Optional[List[FunctionContract]] = None) -> bool:
+    def can_reenter(self, callstack: Optional[List[Union[Function, Variable]]] = None) -> bool:
         """
         Must be called after slithIR analysis pass
         For Solidity > 0.5, filter access to public variables and constant/pure/view
@@ -92,7 +95,7 @@ class NewContract(Call, OperationWithLValue):  # pylint: disable=too-many-instan
 
     # endregion
 
-    def __str__(self):
+    def __str__(self) -> str:
         options = ""
         if self.call_value:
             options = f"value:{self.call_value} "
diff --git a/slither/slithir/operations/solidity_call.py b/slither/slithir/operations/solidity_call.py
index b059c55a6..88430f934 100644
--- a/slither/slithir/operations/solidity_call.py
+++ b/slither/slithir/operations/solidity_call.py
@@ -1,15 +1,16 @@
 from typing import Any, List, Union
-from slither.core.declarations.solidity_variables import SolidityCustomRevert, SolidityFunction
-from slither.slithir.operations.call import Call
-from slither.slithir.operations.lvalue import OperationWithLValue
+
 from slither.core.children.child_node import ChildNode
+from slither.core.declarations.solidity_variables import SolidityFunction
 from slither.core.solidity_types.elementary_type import ElementaryType
+from slither.slithir.operations.call import Call
+from slither.slithir.operations.lvalue import OperationWithLValue
 
 
 class SolidityCall(Call, OperationWithLValue):
     def __init__(
         self,
-        function: Union[SolidityCustomRevert, SolidityFunction],
+        function: SolidityFunction,
         nbr_arguments: int,
         result: ChildNode,
         type_call: Union[str, List[ElementaryType]],
@@ -26,7 +27,7 @@ class SolidityCall(Call, OperationWithLValue):
         return self._unroll(self.arguments)
 
     @property
-    def function(self) -> Union[SolidityCustomRevert, SolidityFunction]:
+    def function(self) -> SolidityFunction:
         return self._function
 
     @property
diff --git a/slither/slithir/utils/utils.py b/slither/slithir/utils/utils.py
index 0a50f8e50..a0ca0bd6f 100644
--- a/slither/slithir/utils/utils.py
+++ b/slither/slithir/utils/utils.py
@@ -1,3 +1,5 @@
+from typing import Union
+
 from slither.core.variables.local_variable import LocalVariable
 from slither.core.variables.state_variable import StateVariable
 
@@ -10,6 +12,24 @@ from slither.slithir.variables.reference import ReferenceVariable
 from slither.slithir.variables.tuple import TupleVariable
 from slither.core.source_mapping.source_mapping import SourceMapping
 
+RVALUE = Union[
+    StateVariable,
+    LocalVariable,
+    TopLevelVariable,
+    TemporaryVariable,
+    Constant,
+    SolidityVariable,
+    ReferenceVariable,
+]
+
+LVALUE = Union[
+    StateVariable,
+    LocalVariable,
+    TemporaryVariable,
+    ReferenceVariable,
+    TupleVariable,
+]
+
 
 def is_valid_rvalue(v: SourceMapping) -> bool:
     return isinstance(
diff --git a/slither/tools/mutator/__main__.py b/slither/tools/mutator/__main__.py
index 27e396d0b..84286ce66 100644
--- a/slither/tools/mutator/__main__.py
+++ b/slither/tools/mutator/__main__.py
@@ -79,9 +79,10 @@ def main() -> None:
     print(args.codebase)
     sl = Slither(args.codebase, **vars(args))
 
-    for M in _get_mutators():
-        m = M(sl)
-        m.mutate()
+    for compilation_unit in sl.compilation_units:
+        for M in _get_mutators():
+            m = M(compilation_unit)
+            m.mutate()
 
 
 # endregion
diff --git a/slither/tools/mutator/mutators/abstract_mutator.py b/slither/tools/mutator/mutators/abstract_mutator.py
index 850c3c399..169d8725e 100644
--- a/slither/tools/mutator/mutators/abstract_mutator.py
+++ b/slither/tools/mutator/mutators/abstract_mutator.py
@@ -3,7 +3,7 @@ import logging
 from enum import Enum
 from typing import Optional, Dict
 
-from slither import Slither
+from slither.core.compilation_unit import SlitherCompilationUnit
 from slither.formatters.utils.patches import apply_patch, create_diff
 
 logger = logging.getLogger("Slither")
@@ -34,8 +34,11 @@ class AbstractMutator(metaclass=abc.ABCMeta):  # pylint: disable=too-few-public-
     FAULTCLASS = FaultClass.Undefined
     FAULTNATURE = FaultNature.Undefined
 
-    def __init__(self, slither: Slither, rate: int = 10, seed: Optional[int] = None):
-        self.slither = slither
+    def __init__(
+        self, compilation_unit: SlitherCompilationUnit, rate: int = 10, seed: Optional[int] = None
+    ):
+        self.compilation_unit = compilation_unit
+        self.slither = compilation_unit.core
         self.seed = seed
         self.rate = rate
 
@@ -87,7 +90,7 @@ class AbstractMutator(metaclass=abc.ABCMeta):  # pylint: disable=too-few-public-
                 continue
             for patch in patches:
                 patched_txt, offset = apply_patch(patched_txt, patch, offset)
-            diff = create_diff(self.slither, original_txt, patched_txt, file)
+            diff = create_diff(self.compilation_unit, original_txt, patched_txt, file)
             if not diff:
                 logger.info(f"Impossible to generate patch; empty {patches}")
             print(diff)