Propagate type aliases from base to derived contracts

slither/solc_parsing/declarations/contract.py

@@ -53,7 +53,7 @@ def __init__(
         self._enumsNotParsed: List[Dict] = []
         self._structuresNotParsed: List[Dict] = []
         self._usingForNotParsed: List[Dict] = []
-        self._customErrorParsed: List[Dict] = []
+        self._customErrorsNotParsed: List[Dict] = []
 
         self._functions_parser: List[FunctionSolc] = []
         self._modifiers_parser: List[ModifierSolc] = []
@@ -277,13 +277,20 @@ def _parse_contract_items(self) -> None:
             elif item[self.get_key()] == "UsingForDirective":
                 self._usingForNotParsed.append(item)
             elif item[self.get_key()] == "ErrorDefinition":
-                self._customErrorParsed.append(item)
+                self._customErrorsNotParsed.append(item)
             elif item[self.get_key()] == "UserDefinedValueTypeDefinition":
                 self._parse_type_alias(item)
             else:
                 raise ParsingError("Unknown contract item: " + item[self.get_key()])
         return
 
+    def parse_type_alias(self) -> None:
+        # We keep parse_ in the name just to keep the naming convention even if we already parsed them initially.
+        # Here we only update the current contract type_aliases_as_dict with the fathers' values
+        # It's useful to keep using the same pattern anyway as we know all the fathers have been analyzed
+        for father in self._contract.inheritance_reverse:
+            self._contract.type_aliases_as_dict.update(father.type_aliases_as_dict)
+
     def _parse_type_alias(self, item: Dict) -> None:
         assert "name" in item
         assert "underlyingType" in item
@@ -337,9 +344,9 @@ def parse_custom_errors(self) -> None:
         for father in self._contract.inheritance_reverse:
             self._contract.custom_errors_as_dict.update(father.custom_errors_as_dict)
 
-        for custom_error in self._customErrorParsed:
+        for custom_error in self._customErrorsNotParsed:
             self._parse_custom_error(custom_error)
-        self._customErrorParsed = []
+        self._customErrorsNotParsed = []
 
     def parse_state_variables(self) -> None:
         for father in self._contract.inheritance_reverse:
@@ -793,7 +800,7 @@ def delete_content(self) -> None:
         self._enumsNotParsed = []
         self._structuresNotParsed = []
         self._usingForNotParsed = []
-        self._customErrorParsed = []
+        self._customErrorsNotParsed = []
 
     def _handle_comment(self, attributes: Dict) -> None:
         """

slither/solc_parsing/slither_compilation_unit_solc.py

@@ -730,6 +730,7 @@ def _parse_struct_var_modifiers_functions(self, contract: ContractSolc) -> None:
         contract.parse_modifiers()
         contract.parse_functions()
         contract.parse_custom_errors()
+        contract.parse_type_alias()
         contract.set_is_analyzed(True)
 
     def _analyze_struct_events(self, contract: ContractSolc) -> None:

tests/e2e/solc_parsing/test_data/expected/type-aliases.sol-0.8.19-compact.json

@@ -1,6 +1,13 @@
 {
   "OtherTest": {
-    "myfunc()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n}\n"
+    "myfunc()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: NEW VARIABLE 2\n\"];\n}\n"
   },
-  "DeleteTest": {}
+  "DeleteTest": {},
+  "A": {
+    "q()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n"
+  },
+  "B": {
+    "q()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "y()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n"
+  }
 }

tests/e2e/solc_parsing/test_data/type-aliases.sol

@@ -21,3 +21,16 @@ contract OtherTest {
 contract DeleteTest {
    type Z is int;
 }
+
+contract A {
+    type MyU is uint256;
+    function q() public returns(MyU) {
+        MyU.wrap(1);
+    }
+}
+
+contract B is A {  
+    function y() public returns(MyU) {
+        return MyU.wrap(343);
+    }
+}