WIP/PoC type.isdynamic

slither/core/solidity_types/array_type.py

@@ -29,6 +29,11 @@ class ArrayType(Type):
     def type(self) -> Type:
         return self._type
 
+
+    @property
+    def is_dynamic(self) -> bool:
+        return self.length is None
+
     @property
     def length(self) -> Optional[Expression]:
         return self._length

slither/core/solidity_types/elementary_type.py

@@ -163,6 +163,10 @@ class ElementaryType(Type):
             t = "bytes1"
         self._type = t
 
+    @property
+    def is_dynamic(self) -> bool:
+        return self._type in ("bytes", "string")
+
     @property
     def type(self) -> str:
         return self._type
@@ -188,7 +192,7 @@ class ElementaryType(Type):
             return int(8)
         if t == "address":
             return int(160)
-        if t.startswith("bytes"):
+        if t.startswith("bytes") and t != "bytes":
             return int(t[len("bytes") :])
         return None
 

slither/core/solidity_types/function_type.py

@@ -32,6 +32,10 @@ class FunctionType(Type):
     def storage_size(self) -> Tuple[int, bool]:
         return 24, False
 
+    @property
+    def is_dynamic(self) -> bool:
+        return False
+
     def __str__(self):
         # Use x.type
         # x.name may be empty

slither/core/solidity_types/mapping_type.py

@@ -23,6 +23,10 @@ class MappingType(Type):
     def storage_size(self) -> Tuple[int, bool]:
         return 32, True
 
+    @property
+    def is_dynamic(self) -> bool:
+        return True
+
     def __str__(self):
         return f"mapping({str(self._from)} => {str(self._to)})"
 

slither/core/solidity_types/type.py

@@ -14,3 +14,8 @@ class Type(SourceMapping, metaclass=abc.ABCMeta):
         :return: (int, bool) - the number of bytes this type will require, and whether it must start in
         a new slot regardless of whether the current slot can still fit it
         """
+
+    @property
+    @abc.abstractmethod
+    def is_dynamic(self) -> bool:
+        """ True if the size of the type is dynamic"""

slither/core/solidity_types/type_alias.py

@@ -22,6 +22,9 @@ class TypeAlias(Type):
     def __hash__(self):
         return hash(str(self))
 
+    @property
+    def is_dynamic(self) -> bool:
+        return self.underlying_type.is_dynamic
 
 class TypeAliasTopLevel(TypeAlias, TopLevel):
     def __init__(self, underlying_type: Type, name: str, scope: "FileScope"):

slither/core/solidity_types/user_defined_type.py

@@ -20,10 +20,15 @@ class UserDefinedType(Type):
         super().__init__()
         self._type = t
 
+    @property
+    def is_dynamic(self) -> bool:
+        raise NotImplemented
+
     @property
     def type(self) -> Union["Contract", "Enum", "Structure"]:
         return self._type
 
+
     @property
     def storage_size(self) -> Tuple[int, bool]:
         from slither.core.declarations.structure import Structure