improve name resolution of type aliases (#2061)

* BREAKING CHANGE: Renamed user_defined_types to type_aliases so it's less confusing with what we call UserDefinedType.
* Added type aliased at the Contract level so now at the file scope there are only top level aliasing and fully qualified contract aliasing like C.myAlias.
* Fix #1809

slither/core/compilation_unit.py

@@ -47,7 +47,7 @@ class SlitherCompilationUnit(Context):
         self._pragma_directives: List[Pragma] = []
         self._import_directives: List[Import] = []
         self._custom_errors: List[CustomErrorTopLevel] = []
-        self._user_defined_value_types: Dict[str, TypeAliasTopLevel] = {}
+        self._type_aliases: Dict[str, TypeAliasTopLevel] = {}
 
         self._all_functions: Set[Function] = set()
         self._all_modifiers: Set[Modifier] = set()
@@ -220,8 +220,8 @@ class SlitherCompilationUnit(Context):
         return self._custom_errors
 
     @property
-    def user_defined_value_types(self) -> Dict[str, TypeAliasTopLevel]:
-        return self._user_defined_value_types
+    def type_aliases(self) -> Dict[str, TypeAliasTopLevel]:
+        return self._type_aliases
 
     # endregion
     ###################################################################################

slither/core/declarations/contract.py

@@ -45,6 +45,7 @@ if TYPE_CHECKING:
     from slither.core.compilation_unit import SlitherCompilationUnit
     from slither.core.scope.scope import FileScope
     from slither.core.cfg.node import Node
+    from slither.core.solidity_types import TypeAliasContract
 
 
 LOGGER = logging.getLogger("Contract")
@@ -81,6 +82,7 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
         self._functions: Dict[str, "FunctionContract"] = {}
         self._linearizedBaseContracts: List[int] = []
         self._custom_errors: Dict[str, "CustomErrorContract"] = {}
+        self._type_aliases: Dict[str, "TypeAliasContract"] = {}
 
         # The only str is "*"
         self._using_for: Dict[USING_FOR_KEY, USING_FOR_ITEM] = {}
@@ -364,6 +366,38 @@ class Contract(SourceMapping):  # pylint: disable=too-many-public-methods
     def custom_errors_as_dict(self) -> Dict[str, "CustomErrorContract"]:
         return self._custom_errors
 
+    # endregion
+    ###################################################################################
+    ###################################################################################
+    # region Custom Errors
+    ###################################################################################
+    ###################################################################################
+
+    @property
+    def type_aliases(self) -> List["TypeAliasContract"]:
+        """
+        list(TypeAliasContract): List of the contract's custom errors
+        """
+        return list(self._type_aliases.values())
+
+    @property
+    def type_aliases_inherited(self) -> List["TypeAliasContract"]:
+        """
+        list(TypeAliasContract): List of the inherited custom errors
+        """
+        return [s for s in self.type_aliases if s.contract != self]
+
+    @property
+    def type_aliases_declared(self) -> List["TypeAliasContract"]:
+        """
+        list(TypeAliasContract): List of the custom errors declared within the contract (not inherited)
+        """
+        return [s for s in self.type_aliases if s.contract == self]
+
+    @property
+    def type_aliases_as_dict(self) -> Dict[str, "TypeAliasContract"]:
+        return self._type_aliases
+
     # endregion
     ###################################################################################
     ###################################################################################

slither/core/scope/scope.py

@@ -52,7 +52,7 @@ class FileScope:
 
         # User defined types
         # Name -> type alias
-        self.user_defined_types: Dict[str, TypeAlias] = {}
+        self.type_aliases: Dict[str, TypeAlias] = {}
 
     def add_accesible_scopes(self) -> bool:
         """
@@ -95,8 +95,8 @@ class FileScope:
             if not _dict_contain(new_scope.renaming, self.renaming):
                 self.renaming.update(new_scope.renaming)
                 learn_something = True
-            if not _dict_contain(new_scope.user_defined_types, self.user_defined_types):
-                self.user_defined_types.update(new_scope.user_defined_types)
+            if not _dict_contain(new_scope.type_aliases, self.type_aliases):
+                self.type_aliases.update(new_scope.type_aliases)
                 learn_something = True
 
         return learn_something

slither/solc_parsing/declarations/contract.py

@@ -291,10 +291,10 @@ class ContractSolc(CallerContextExpression):
         alias = item["name"]
         alias_canonical = self._contract.name + "." + item["name"]
 
-        user_defined_type = TypeAliasContract(original_type, alias, self.underlying_contract)
-        user_defined_type.set_offset(item["src"], self.compilation_unit)
-        self._contract.file_scope.user_defined_types[alias] = user_defined_type
-        self._contract.file_scope.user_defined_types[alias_canonical] = user_defined_type
+        type_alias = TypeAliasContract(original_type, alias, self.underlying_contract)
+        type_alias.set_offset(item["src"], self.compilation_unit)
+        self._contract.type_aliases_as_dict[alias] = type_alias
+        self._contract.file_scope.type_aliases[alias_canonical] = type_alias
 
     def _parse_struct(self, struct: Dict) -> None:
 

slither/solc_parsing/declarations/using_for_top_level.py

@@ -152,7 +152,7 @@ class UsingForTopLevelSolc(CallerContextExpression):  # pylint: disable=too-few-
         if self._global:
             for scope in self.compilation_unit.scopes.values():
                 if isinstance(type_name, TypeAliasTopLevel):
-                    for alias in scope.user_defined_types.values():
+                    for alias in scope.type_aliases.values():
                         if alias == type_name:
                             scope.using_for_directives.add(self._using_for)
                 elif isinstance(type_name, UserDefinedType):

slither/solc_parsing/expressions/find_variable.py

@@ -114,6 +114,8 @@ def find_top_level(
     :return:
     :rtype:
     """
+    if var_name in scope.type_aliases:
+        return scope.type_aliases[var_name], False
 
     if var_name in scope.structures:
         return scope.structures[var_name], False
@@ -205,6 +207,10 @@ def _find_in_contract(
                 if sig == var_name:
                     return modifier
 
+    type_aliases = contract.type_aliases_as_dict
+    if var_name in type_aliases:
+        return type_aliases[var_name]
+
     # structures are looked on the contract declarer
     structures = contract.structures_as_dict
     if var_name in structures:
@@ -362,9 +368,6 @@ def find_variable(
     if var_name in current_scope.renaming:
         var_name = current_scope.renaming[var_name]
 
-    if var_name in current_scope.user_defined_types:
-        return current_scope.user_defined_types[var_name], False
-
     # Use ret0/ret1 to help mypy
     ret0 = _find_variable_from_ref_declaration(
         referenced_declaration, direct_contracts, direct_functions

slither/solc_parsing/slither_compilation_unit_solc.py

@@ -344,10 +344,10 @@ class SlitherCompilationUnitSolc(CallerContextExpression):
 
                 original_type = ElementaryType(underlying_type["name"])
 
-                user_defined_type = TypeAliasTopLevel(original_type, alias, scope)
-                user_defined_type.set_offset(top_level_data["src"], self._compilation_unit)
-                self._compilation_unit.user_defined_value_types[alias] = user_defined_type
-                scope.user_defined_types[alias] = user_defined_type
+                type_alias = TypeAliasTopLevel(original_type, alias, scope)
+                type_alias.set_offset(top_level_data["src"], self._compilation_unit)
+                self._compilation_unit.type_aliases[alias] = type_alias
+                scope.type_aliases[alias] = type_alias
 
             else:
                 raise SlitherException(f"Top level {top_level_data[self.get_key()]} not supported")

slither/solc_parsing/solidity_types/type_parsing.py

@@ -235,7 +235,7 @@ def parse_type(
 
     sl: "SlitherCompilationUnit"
     renaming: Dict[str, str]
-    user_defined_types: Dict[str, TypeAlias]
+    type_aliases: 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
@@ -247,13 +247,13 @@ def parse_type(
             sl = caller_context.compilation_unit
             next_context = caller_context
             renaming = {}
-            user_defined_types = sl.user_defined_value_types
+            type_aliases = sl.type_aliases
         else:
             assert isinstance(caller_context, FunctionSolc)
             sl = caller_context.underlying_function.compilation_unit
             next_context = caller_context.slither_parser
             renaming = caller_context.underlying_function.file_scope.renaming
-            user_defined_types = caller_context.underlying_function.file_scope.user_defined_types
+            type_aliases = caller_context.underlying_function.file_scope.type_aliases
         structures_direct_access = sl.structures_top_level
         all_structuress = [c.structures for c in sl.contracts]
         all_structures = [item for sublist in all_structuress for item in sublist]
@@ -299,7 +299,7 @@ def parse_type(
         functions = list(scope.functions)
 
         renaming = scope.renaming
-        user_defined_types = scope.user_defined_types
+        type_aliases = scope.type_aliases
     elif isinstance(caller_context, (ContractSolc, FunctionSolc)):
         sl = caller_context.compilation_unit
         if isinstance(caller_context, FunctionSolc):
@@ -329,7 +329,7 @@ def parse_type(
         functions = contract.functions + contract.modifiers
 
         renaming = scope.renaming
-        user_defined_types = scope.user_defined_types
+        type_aliases = scope.type_aliases
     else:
         raise ParsingError(f"Incorrect caller context: {type(caller_context)}")
 
@@ -343,8 +343,8 @@ def parse_type(
         name = t.name
         if name in renaming:
             name = renaming[name]
-        if name in user_defined_types:
-            return user_defined_types[name]
+        if name in type_aliases:
+            return type_aliases[name]
         return _find_from_type_name(
             name,
             functions,
@@ -365,9 +365,9 @@ def parse_type(
             name = t["typeDescriptions"]["typeString"]
             if name in renaming:
                 name = renaming[name]
-            if name in user_defined_types:
-                _add_type_references(user_defined_types[name], t["src"], sl)
-                return user_defined_types[name]
+            if name in type_aliases:
+                _add_type_references(type_aliases[name], t["src"], sl)
+                return type_aliases[name]
             type_found = _find_from_type_name(
                 name,
                 functions,
@@ -386,9 +386,9 @@ def parse_type(
         name = t["attributes"][type_name_key]
         if name in renaming:
             name = renaming[name]
-        if name in user_defined_types:
-            _add_type_references(user_defined_types[name], t["src"], sl)
-            return user_defined_types[name]
+        if name in type_aliases:
+            _add_type_references(type_aliases[name], t["src"], sl)
+            return type_aliases[name]
         type_found = _find_from_type_name(
             name,
             functions,
@@ -407,8 +407,8 @@ def parse_type(
             name = t["name"]
             if name in renaming:
                 name = renaming[name]
-            if name in user_defined_types:
-                return user_defined_types[name]
+            if name in type_aliases:
+                return type_aliases[name]
             type_found = _find_from_type_name(
                 name,
                 functions,

slither/visitors/slithir/expression_to_slithir.py

@@ -516,8 +516,8 @@ class ExpressionToSlithIR(ExpressionVisitor):
             # contract A { type MyInt is int}
             # contract B { function f() public{ A.MyInt test = A.MyInt.wrap(1);}}
             # The logic is handled by _post_call_expression
-            if expression.member_name in expr.file_scope.user_defined_types:
-                set_val(expression, expr.file_scope.user_defined_types[expression.member_name])
+            if expression.member_name in expr.file_scope.type_aliases:
+                set_val(expression, expr.file_scope.type_aliases[expression.member_name])
                 return
             # Lookup errors referred to as member of contract e.g. Test.myError.selector
             if expression.member_name in expr.custom_errors_as_dict:

tests/e2e/solc_parsing/test_ast_parsing.py

@@ -459,6 +459,7 @@ ALL_TESTS = [
         ["0.6.9", "0.7.6", "0.8.16"],
     ),
     Test("user_defined_operators-0.8.19.sol", ["0.8.19"]),
+    Test("type-aliases.sol", ["0.8.19"]),
 ]
 # create the output folder if needed
 try:

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

@@ -0,0 +1,6 @@
+{
+  "OtherTest": {
+    "myfunc()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n}\n"
+  },
+  "DeleteTest": {}
+}

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

@@ -0,0 +1,20 @@
+
+struct Z {
+    int x;
+    int y;
+}
+
+contract OtherTest {
+    struct Z {
+        int x;
+        int y;
+    }
+
+    function myfunc() external {
+        Z memory z = Z(2,3);
+    }
+}
+
+contract DeleteTest {
+   type Z is int;
+}

tests/unit/core/test_source_mapping.py

@@ -85,15 +85,13 @@ def test_references_user_defined_aliases(solc_binary_path):
     file = Path(SRC_MAPPING_TEST_ROOT, "ReferencesUserDefinedAliases.sol").as_posix()
     slither = Slither(file, solc=solc_path)
 
-    alias_top_level = slither.compilation_units[0].user_defined_value_types["aliasTopLevel"]
+    alias_top_level = slither.compilation_units[0].type_aliases["aliasTopLevel"]
     assert len(alias_top_level.references) == 2
     lines = _sort_references_lines(alias_top_level.references)
     assert lines == [12, 16]
 
     alias_contract_level = (
-        slither.compilation_units[0]
-        .contracts[0]
-        .file_scope.user_defined_types["C.aliasContractLevel"]
+        slither.compilation_units[0].contracts[0].file_scope.type_aliases["C.aliasContractLevel"]
     )
     assert len(alias_contract_level.references) == 2
     lines = _sort_references_lines(alias_contract_level.references)