diff --git a/slither/core/children/child_expression.py b/slither/core/children/child_expression.py
index 102e267b3..0064658c0 100644
--- a/slither/core/children/child_expression.py
+++ b/slither/core/children/child_expression.py
@@ -1,7 +1,8 @@
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Union
 
 if TYPE_CHECKING:
     from slither.core.expressions.expression import Expression
+    from slither.slithir.operations import Operation
 
 
 class ChildExpression:
@@ -9,9 +10,9 @@ class ChildExpression:
         super().__init__()
         self._expression = None
 
-    def set_expression(self, expression: "Expression") -> None:
+    def set_expression(self, expression: Union["Expression", "Operation"]) -> None:
         self._expression = expression
 
     @property
-    def expression(self) -> "Expression":
+    def expression(self) -> Union["Expression", "Operation"]:
         return self._expression
diff --git a/slither/core/declarations/__init__.py b/slither/core/declarations/__init__.py
index f891ad621..92e0b9eca 100644
--- a/slither/core/declarations/__init__.py
+++ b/slither/core/declarations/__init__.py
@@ -17,3 +17,4 @@ from .structure_contract import StructureContract
 from .structure_top_level import StructureTopLevel
 from .function_contract import FunctionContract
 from .function_top_level import FunctionTopLevel
+from .custom_error_contract import CustomErrorContract
diff --git a/slither/core/declarations/contract.py b/slither/core/declarations/contract.py
index 6d787294f..2d2d10b04 100644
--- a/slither/core/declarations/contract.py
+++ b/slither/core/declarations/contract.py
@@ -38,13 +38,13 @@ if TYPE_CHECKING:
         EnumContract,
         StructureContract,
         FunctionContract,
+        CustomErrorContract,
     )
     from slither.slithir.variables.variable import SlithIRVariable
-    from slither.core.variables.variable import Variable
-    from slither.core.variables.state_variable import StateVariable
+    from slither.core.variables import Variable, StateVariable
     from slither.core.compilation_unit import SlitherCompilationUnit
-    from slither.core.declarations.custom_error_contract import CustomErrorContract
     from slither.core.scope.scope import FileScope
+    from slither.core.cfg.node import Node
 
 
 LOGGER = logging.getLogger("Contract")
@@ -803,23 +803,25 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
         """
         return next((v for v in self.state_variables if v.name == canonical_name), None)
 
-    def get_structure_from_name(self, structure_name: str) -> Optional["Structure"]:
+    def get_structure_from_name(self, structure_name: str) -> Optional["StructureContract"]:
         """
             Return a structure from a name
         Args:
             structure_name (str): name of the structure
         Returns:
-            Structure
+            StructureContract
         """
         return next((st for st in self.structures if st.name == structure_name), None)
 
-    def get_structure_from_canonical_name(self, structure_name: str) -> Optional["Structure"]:
+    def get_structure_from_canonical_name(
+        self, structure_name: str
+    ) -> Optional["StructureContract"]:
         """
             Return a structure from a canonical name
         Args:
             structure_name (str): canonical name of the structure
         Returns:
-            Structure
+            StructureContract
         """
         return next((st for st in self.structures if st.canonical_name == structure_name), None)
 
diff --git a/slither/core/declarations/using_for_top_level.py b/slither/core/declarations/using_for_top_level.py
index 2c8dfc9b8..27d1f90e4 100644
--- a/slither/core/declarations/using_for_top_level.py
+++ b/slither/core/declarations/using_for_top_level.py
@@ -14,5 +14,5 @@ class UsingForTopLevel(TopLevel):
         self.file_scope: "FileScope" = scope
 
     @property
-    def using_for(self) -> Dict[Type, List[Type]]:
+    def using_for(self) -> Dict[Union[str, Type], List[Type]]:
         return self._using_for
diff --git a/slither/core/slither_core.py b/slither/core/slither_core.py
index ff6df04f0..e5f4e830a 100644
--- a/slither/core/slither_core.py
+++ b/slither/core/slither_core.py
@@ -8,7 +8,7 @@ import pathlib
 import posixpath
 import re
 from collections import defaultdict
-from typing import Optional, Dict, List, Set, Union
+from typing import Optional, Dict, List, Set, Union, Tuple
 
 from crytic_compile import CryticCompile
 from crytic_compile.utils.naming import Filename
@@ -73,8 +73,8 @@ class SlitherCore(Context):
 
         # Maps from file to detector name to the start/end ranges for that detector.
         # Infinity is used to signal a detector has no end range.
-        self._ignore_ranges: defaultdict[str, defaultdict[str, List[(int, int)]]] = defaultdict(
-            lambda: defaultdict(lambda: [])
+        self._ignore_ranges: Dict[str, Dict[str, List[Tuple[int, ...]]]] = defaultdict(
+            lambda: defaultdict(lambda: [(-1, -1)])
         )
 
         self._compilation_units: List[SlitherCompilationUnit] = []
diff --git a/slither/core/solidity_types/array_type.py b/slither/core/solidity_types/array_type.py
index c873c639a..9a0b12c00 100644
--- a/slither/core/solidity_types/array_type.py
+++ b/slither/core/solidity_types/array_type.py
@@ -17,7 +17,7 @@ class ArrayType(Type):
     def __init__(
         self,
         t: Union["TypeAliasTopLevel", "ArrayType", "FunctionType", "ElementaryType"],
-        length: Optional[Union["Identifier", Literal, "BinaryOperation"]],
+        length: Optional[Union["Identifier", Literal, "BinaryOperation", int]],
     ) -> None:
         assert isinstance(t, Type)
         if length:
diff --git a/slither/core/solidity_types/function_type.py b/slither/core/solidity_types/function_type.py
index 4682bcf19..b73d9fa84 100644
--- a/slither/core/solidity_types/function_type.py
+++ b/slither/core/solidity_types/function_type.py
@@ -1,4 +1,4 @@
-from typing import List, Tuple
+from typing import List, Tuple, Any
 
 from slither.core.solidity_types.type import Type
 from slither.core.variables.function_type_variable import FunctionTypeVariable
@@ -69,7 +69,7 @@ class FunctionType(Type):
             return f"({params}) returns({return_values})"
         return f"({params})"
 
-    def __eq__(self, other: ElementaryType) -> bool:
+    def __eq__(self, other: Any) -> bool:
         if not isinstance(other, FunctionType):
             return False
         return self.params == other.params and self.return_values == other.return_values
diff --git a/slither/core/solidity_types/type_alias.py b/slither/core/solidity_types/type_alias.py
index b202d3608..5b9ea0a37 100644
--- a/slither/core/solidity_types/type_alias.py
+++ b/slither/core/solidity_types/type_alias.py
@@ -2,7 +2,7 @@ from typing import TYPE_CHECKING, Tuple
 
 from slither.core.children.child_contract import ChildContract
 from slither.core.declarations.top_level import TopLevel
-from slither.core.solidity_types import Type
+from slither.core.solidity_types import Type, ElementaryType
 
 if TYPE_CHECKING:
     from slither.core.declarations import Contract
@@ -10,13 +10,13 @@ if TYPE_CHECKING:
 
 
 class TypeAlias(Type):
-    def __init__(self, underlying_type: Type, name: str) -> None:
+    def __init__(self, underlying_type: ElementaryType, name: str) -> None:
         super().__init__()
         self.name = name
         self.underlying_type = underlying_type
 
     @property
-    def type(self) -> Type:
+    def type(self) -> ElementaryType:
         """
         Return the underlying type. Alias for underlying_type
 
diff --git a/slither/core/solidity_types/type_information.py b/slither/core/solidity_types/type_information.py
index dd0aeec43..2af0b097a 100644
--- a/slither/core/solidity_types/type_information.py
+++ b/slither/core/solidity_types/type_information.py
@@ -5,13 +5,13 @@ from slither.core.solidity_types.type import Type
 
 if TYPE_CHECKING:
     from slither.core.declarations.contract import Contract
-    from slither.core.declarations.enum_top_level import EnumTopLevel
+    from slither.core.declarations.enum import Enum
 
 
 # Use to model the Type(X) function, which returns an undefined type
 # https://solidity.readthedocs.io/en/latest/units-and-global-variables.html#type-information
 class TypeInformation(Type):
-    def __init__(self, c: Union[ElementaryType, "Contract", "EnumTopLevel"]) -> None:
+    def __init__(self, c: Union[ElementaryType, "Contract", "Enum"]) -> None:
         # pylint: disable=import-outside-toplevel
         from slither.core.declarations.contract import Contract
         from slither.core.declarations.enum import Enum
@@ -21,7 +21,7 @@ class TypeInformation(Type):
         self._type = c
 
     @property
-    def type(self) -> "Contract":
+    def type(self) -> Union["Contract", ElementaryType, "Enum"]:
         return self._type
 
     @property
diff --git a/slither/core/solidity_types/user_defined_type.py b/slither/core/solidity_types/user_defined_type.py
index a78497fd9..8de41116f 100644
--- a/slither/core/solidity_types/user_defined_type.py
+++ b/slither/core/solidity_types/user_defined_type.py
@@ -8,14 +8,10 @@ if TYPE_CHECKING:
     from slither.core.declarations.structure import Structure
     from slither.core.declarations.enum import Enum
     from slither.core.declarations.contract import Contract
-    from slither.core.declarations import EnumContract
-    from slither.core.declarations.structure_top_level import StructureTopLevel
 
 # pylint: disable=import-outside-toplevel
 class UserDefinedType(Type):
-    def __init__(
-        self, t: Union["EnumContract", "StructureTopLevel", "Contract", "StructureContract"]
-    ) -> None:
+    def __init__(self, t: Union["Enum", "Contract", "Structure"]) -> None:
         from slither.core.declarations.structure import Structure
         from slither.core.declarations.enum import Enum
         from slither.core.declarations.contract import Contract
diff --git a/slither/core/variables/__init__.py b/slither/core/variables/__init__.py
index e69de29bb..638f0f3a4 100644
--- a/slither/core/variables/__init__.py
+++ b/slither/core/variables/__init__.py
@@ -0,0 +1,2 @@
+from .state_variable import StateVariable
+from .variable import Variable
diff --git a/slither/slithir/operations/phi_callback.py b/slither/slithir/operations/phi_callback.py
index 34a488f98..0c8994056 100644
--- a/slither/slithir/operations/phi_callback.py
+++ b/slither/slithir/operations/phi_callback.py
@@ -38,6 +38,10 @@ class PhiCallback(Phi):
     def rvalues(self):
         return self._rvalues
 
+    @rvalues.setter
+    def rvalues(self, vals):
+        self._rvalues = vals
+
     @property
     def rvalue_no_callback(self):
         """
@@ -45,10 +49,6 @@ class PhiCallback(Phi):
         """
         return self._rvalue_no_callback
 
-    @rvalues.setter
-    def rvalues(self, vals):
-        self._rvalues = vals
-
     @property
     def nodes(self):
         return self._nodes
diff --git a/slither/slithir/variables/constant.py b/slither/slithir/variables/constant.py
index e787bc396..ddfc9e054 100644
--- a/slither/slithir/variables/constant.py
+++ b/slither/slithir/variables/constant.py
@@ -11,7 +11,7 @@ from slither.utils.integer_conversion import convert_string_to_int
 class Constant(SlithIRVariable):
     def __init__(
         self,
-        val: str,
+        val: Union[int, str],
         constant_type: Optional[ElementaryType] = None,
         subdenomination: Optional[str] = None,
     ) -> None:  # pylint: disable=too-many-branches
diff --git a/slither/slithir/variables/local_variable.py b/slither/slithir/variables/local_variable.py
index 627629bc5..eb32d4024 100644
--- a/slither/slithir/variables/local_variable.py
+++ b/slither/slithir/variables/local_variable.py
@@ -1,3 +1,4 @@
+from typing import Set
 from slither.core.variables.local_variable import LocalVariable
 from slither.slithir.variables.temporary import TemporaryVariable
 from slither.slithir.variables.variable import SlithIRVariable
@@ -31,7 +32,7 @@ class LocalIRVariable(
 
         # Additional field
         # points to state variables
-        self._refers_to = set()
+        self._refers_to: Set[StateIRVariable] = set()
 
         # keep un-ssa version
         if isinstance(local_variable, LocalIRVariable):
diff --git a/slither/slithir/variables/reference.py b/slither/slithir/variables/reference.py
index 978e4f737..95802b7e2 100644
--- a/slither/slithir/variables/reference.py
+++ b/slither/slithir/variables/reference.py
@@ -35,13 +35,6 @@ class ReferenceVariable(ChildNode, Variable):
         """
         return self._points_to
 
-    @property
-    def points_to_origin(self):
-        points = self.points_to
-        while isinstance(points, ReferenceVariable):
-            points = points.points_to
-        return points
-
     @points_to.setter
     def points_to(self, points_to):
         # Can only be a rvalue of
@@ -55,6 +48,13 @@ class ReferenceVariable(ChildNode, Variable):
 
         self._points_to = points_to
 
+    @property
+    def points_to_origin(self):
+        points = self.points_to
+        while isinstance(points, ReferenceVariable):
+            points = points.points_to
+        return points
+
     @property
     def name(self) -> str:
         return f"REF_{self.index}"
diff --git a/slither/solc_parsing/declarations/function.py b/slither/solc_parsing/declarations/function.py
index af9e14bb1..9671d9bbe 100644
--- a/slither/solc_parsing/declarations/function.py
+++ b/slither/solc_parsing/declarations/function.py
@@ -1,5 +1,5 @@
 import logging
-from typing import Dict, Optional, Union, List, TYPE_CHECKING
+from typing import Dict, Optional, Union, List, TYPE_CHECKING, Tuple
 
 from slither.core.cfg.node import NodeType, link_nodes, insert_node, Node
 from slither.core.cfg.scope import Scope
@@ -445,7 +445,7 @@ class FunctionSolc(CallerContextExpression):
 
     def _parse_for_compact_ast(  # pylint: disable=no-self-use
         self, statement: Dict
-    ) -> (Optional[Dict], Optional[Dict], Optional[Dict], Dict):
+    ) -> Tuple[Optional[Dict], Optional[Dict], Optional[Dict], Dict]:
         body = statement["body"]
         init_expression = statement.get("initializationExpression", None)
         condition = statement.get("condition", None)
@@ -455,7 +455,7 @@ class FunctionSolc(CallerContextExpression):
 
     def _parse_for_legacy_ast(
         self, statement: Dict
-    ) -> (Optional[Dict], Optional[Dict], Optional[Dict], Dict):
+    ) -> Tuple[Optional[Dict], Optional[Dict], Optional[Dict], Dict]:
         # if we're using an old version of solc (anything below and including 0.4.11) or if the user
         # explicitly enabled compact ast, we might need to make some best-effort guesses
         children = statement[self.get_children("children")]
diff --git a/slither/solc_parsing/solidity_types/type_parsing.py b/slither/solc_parsing/solidity_types/type_parsing.py
index e289090b1..7a52ddb0a 100644
--- a/slither/solc_parsing/solidity_types/type_parsing.py
+++ b/slither/solc_parsing/solidity_types/type_parsing.py
@@ -22,7 +22,7 @@ from slither.solc_parsing.exceptions import ParsingError
 from slither.solc_parsing.expressions.expression_parsing import CallerContextExpression
 
 if TYPE_CHECKING:
-    from slither.core.declarations import Structure, Enum
+    from slither.core.declarations import Structure, Enum, Function
     from slither.core.declarations.contract import Contract
     from slither.core.compilation_unit import SlitherCompilationUnit
     from slither.solc_parsing.slither_compilation_unit_solc import SlitherCompilationUnitSolc
@@ -233,6 +233,7 @@ def parse_type(
     sl: "SlitherCompilationUnit"
     renaming: Dict[str, str]
     user_defined_types: Dict[str, TypeAlias]
+    enums_direct_access: List["Enum"] = []
     # Note: for convenicence top level functions use the same parser than function in contract
     # but contract_parser is set to None
     if isinstance(caller_context, SlitherCompilationUnitSolc) or (
@@ -254,7 +255,7 @@ def parse_type(
         all_structuress = [c.structures for c in sl.contracts]
         all_structures = [item for sublist in all_structuress for item in sublist]
         all_structures += structures_direct_access
-        enums_direct_access = sl.enums_top_level
+        enums_direct_access += sl.enums_top_level
         all_enumss = [c.enums for c in sl.contracts]
         all_enums = [item for sublist in all_enumss for item in sublist]
         all_enums += enums_direct_access
@@ -316,7 +317,7 @@ def parse_type(
         all_structuress = [c.structures for c in contract.file_scope.contracts.values()]
         all_structures = [item for sublist in all_structuress for item in sublist]
         all_structures += contract.file_scope.structures.values()
-        enums_direct_access: List["Enum"] = contract.enums
+        enums_direct_access += contract.enums
         enums_direct_access += contract.file_scope.enums.values()
         all_enumss = [c.enums for c in contract.file_scope.contracts.values()]
         all_enums = [item for sublist in all_enumss for item in sublist]
diff --git a/slither/solc_parsing/variables/variable_declaration.py b/slither/solc_parsing/variables/variable_declaration.py
index 79f9f3dac..d21d89875 100644
--- a/slither/solc_parsing/variables/variable_declaration.py
+++ b/slither/solc_parsing/variables/variable_declaration.py
@@ -1,6 +1,6 @@
 import logging
 import re
-from typing import Dict
+from typing import Dict, Optional
 
 from slither.solc_parsing.declarations.caller_context import CallerContextExpression
 from slither.solc_parsing.expressions.expression_parsing import parse_expression
@@ -127,7 +127,7 @@ class VariableDeclarationSolc:
             self._variable.visibility = "internal"
 
     def _init_from_declaration(
-        self, var: Dict, init: bool
+        self, var: Dict, init: Optional[bool]
     ) -> None:  # pylint: disable=too-many-branches
         if self._is_compact_ast:
             attributes = var
diff --git a/slither/visitors/expression/constants_folding.py b/slither/visitors/expression/constants_folding.py
index e42349a03..5f419ef99 100644
--- a/slither/visitors/expression/constants_folding.py
+++ b/slither/visitors/expression/constants_folding.py
@@ -8,6 +8,8 @@ from slither.core.expressions import (
     Identifier,
     BinaryOperation,
     UnaryOperation,
+    TupleExpression,
+    TypeConversion,
 )
 
 from slither.utils.integer_conversion import convert_string_to_fraction, convert_string_to_int
@@ -23,7 +25,9 @@ class NotConstant(Exception):
 
 KEY = "ConstantFolding"
 
-CONSTANT_TYPES_OPERATIONS = Union[Literal, BinaryOperation, UnaryOperation, Identifier]
+CONSTANT_TYPES_OPERATIONS = Union[
+    Literal, BinaryOperation, UnaryOperation, Identifier, TupleExpression, TypeConversion
+]
 
 
 def get_val(expression: CONSTANT_TYPES_OPERATIONS) -> Union[bool, int, Fraction, str]:
diff --git a/slither/visitors/slithir/expression_to_slithir.py b/slither/visitors/slithir/expression_to_slithir.py
index b6f8313aa..46f11b016 100644
--- a/slither/visitors/slithir/expression_to_slithir.py
+++ b/slither/visitors/slithir/expression_to_slithir.py
@@ -1,7 +1,6 @@
 import logging
-from typing import Any, Union, List, TYPE_CHECKING
+from typing import Any, Union, List, TYPE_CHECKING, TypeVar, Generic
 
-import slither.slithir.variables.reference
 from slither.core.declarations import (
     Function,
     SolidityVariable,
@@ -67,13 +66,14 @@ from slither.visitors.expression.expression import ExpressionVisitor
 
 if TYPE_CHECKING:
     from slither.core.cfg.node import Node
+    from slither.slithir.operations import Operation
 
 logger = logging.getLogger("VISTIOR:ExpressionToSlithIR")
 
 key = "expressionToSlithIR"
 
 
-def get(expression: Expression):
+def get(expression: Union[Expression, Operation]):
     val = expression.context[key]
     # we delete the item to reduce memory use
     del expression.context[key]
@@ -84,7 +84,7 @@ def get_without_removing(expression):
     return expression.context[key]
 
 
-def set_val(expression: Expression, val) -> None:
+def set_val(expression: Union[Expression, Operation], val) -> None:
     expression.context[key] = val
 
 
@@ -121,7 +121,7 @@ _signed_to_unsigned = {
 
 def convert_assignment(
     left: Union[LocalVariable, StateVariable, ReferenceVariable],
-    right: SourceMapping,
+    right: Union[LocalVariable, StateVariable, ReferenceVariable],
     t: AssignmentOperationType,
     return_type,
 ) -> Union[Binary, Assignment]:
@@ -417,9 +417,7 @@ class ExpressionToSlithIR(ExpressionVisitor):
         cst = Constant(expression.value, expression.type, expression.subdenomination)
         set_val(expression, cst)
 
-    def _post_member_access(
-        self, expression: slither.core.expressions.member_access.MemberAccess
-    ) -> None:
+    def _post_member_access(self, expression: MemberAccess) -> None:
         expr = get(expression.expression)
 
         # Look for type(X).max / min
@@ -541,9 +539,7 @@ class ExpressionToSlithIR(ExpressionVisitor):
             val = expressions
         set_val(expression, val)
 
-    def _post_type_conversion(
-        self, expression: slither.core.expressions.type_conversion.TypeConversion
-    ) -> None:
+    def _post_type_conversion(self, expression: TypeConversion) -> None:
         expr = get(expression.expression)
         val = TemporaryVariable(self._node)
         operation = TypeConversion(val, expr, expression.type)