Support user defined operators

slither/core/solidity_types/type_alias.py

@@ -1,10 +1,11 @@
-from typing import TYPE_CHECKING, Tuple
+from typing import TYPE_CHECKING, Tuple, Dict
 
 from slither.core.declarations.top_level import TopLevel
 from slither.core.declarations.contract_level import ContractLevel
 from slither.core.solidity_types import Type, ElementaryType
 
 if TYPE_CHECKING:
+    from slither.core.declarations.function_top_level import FunctionTopLevel
     from slither.core.declarations import Contract
     from slither.core.scope.scope import FileScope
 
@@ -43,6 +44,8 @@ class TypeAliasTopLevel(TypeAlias, TopLevel):
     def __init__(self, underlying_type: ElementaryType, name: str, scope: "FileScope") -> None:
         super().__init__(underlying_type, name)
         self.file_scope: "FileScope" = scope
+        # operators redefined
+        self.operators: Dict[str, "FunctionTopLevel"] = {}
 
     def __str__(self) -> str:
         return self.name

slither/solc_parsing/declarations/using_for_top_level.py

@@ -55,22 +55,29 @@ def analyze(self) -> None:
             self._propagate_global(type_name)
         else:
             for f in self._functions:
-                full_name_split = f["function"]["name"].split(".")
-                if len(full_name_split) == 1:
+                # User defined operator
+                if "operator" in f:
                     # Top level function
-                    function_name: str = full_name_split[0]
-                    self._analyze_top_level_function(function_name, type_name)
-                elif len(full_name_split) == 2:
-                    # It can be a top level function behind an aliased import
-                    # or a library function
-                    first_part = full_name_split[0]
-                    function_name = full_name_split[1]
-                    self._check_aliased_import(first_part, function_name, type_name)
+                    function_name: str = f["definition"]["name"]
+                    operator: str = f["operator"]
+                    self._analyze_operator(operator, function_name, type_name)
                 else:
-                    # MyImport.MyLib.a we don't care of the alias
-                    library_name_str = full_name_split[1]
-                    function_name = full_name_split[2]
-                    self._analyze_library_function(library_name_str, function_name, type_name)
+                    full_name_split = f["function"]["name"].split(".")
+                    if len(full_name_split) == 1:
+                        # Top level function
+                        function_name: str = full_name_split[0]
+                        self._analyze_top_level_function(function_name, type_name)
+                    elif len(full_name_split) == 2:
+                        # It can be a top level function behind an aliased import
+                        # or a library function
+                        first_part = full_name_split[0]
+                        function_name = full_name_split[1]
+                        self._check_aliased_import(first_part, function_name, type_name)
+                    else:
+                        # MyImport.MyLib.a we don't care of the alias
+                        library_name_str = full_name_split[1]
+                        function_name = full_name_split[2]
+                        self._analyze_library_function(library_name_str, function_name, type_name)
 
     def _check_aliased_import(
         self,
@@ -101,6 +108,19 @@ def _analyze_top_level_function(
                 self._propagate_global(type_name)
                 break
 
+    def _analyze_operator(
+        self, operator: str, function_name: str, type_name: TypeAliasTopLevel
+    ) -> None:
+        for tl_function in self._using_for.file_scope.functions:
+            # The library function is bound to the first parameter's type
+            if (
+                tl_function.name == function_name
+                and tl_function.parameters
+                and type_name == tl_function.parameters[0].type
+            ):
+                type_name.operators[operator] = tl_function
+                break
+
     def _analyze_library_function(
         self,
         library_name: str,

slither/solc_parsing/expressions/expression_parsing.py

@@ -1,6 +1,6 @@
 import logging
 import re
-from typing import Union, Dict, TYPE_CHECKING
+from typing import Union, Dict, TYPE_CHECKING, List, Any
 
 import slither.core.expressions.type_conversion
 from slither.core.declarations.solidity_variables import (
@@ -236,6 +236,24 @@ def _parse_elementary_type_name_expression(
     pass
 
 
+def _user_defined_op_call(
+    caller_context: CallerContextExpression, src, function_id: int, args: List[Any], type_call: str
+) -> CallExpression:
+    var, was_created = find_variable(None, caller_context, function_id)
+
+    if was_created:
+        var.set_offset(src, caller_context.compilation_unit)
+
+    identifier = Identifier(var)
+    identifier.set_offset(src, caller_context.compilation_unit)
+
+    var.references.append(identifier.source_mapping)
+
+    call = CallExpression(identifier, args, type_call)
+    call.set_offset(src, caller_context.compilation_unit)
+    return call
+
+
 def parse_expression(expression: Dict, caller_context: CallerContextExpression) -> "Expression":
     # pylint: disable=too-many-nested-blocks,too-many-statements
     """
@@ -274,34 +292,50 @@ def parse_expression(expression: Dict, caller_context: CallerContextExpression)
     if name == "UnaryOperation":
         if is_compact_ast:
             attributes = expression
-        else:
-            attributes = expression["attributes"]
-        assert "prefix" in attributes
-        operation_type = UnaryOperationType.get_type(attributes["operator"], attributes["prefix"])
-
-        if is_compact_ast:
             expression = parse_expression(expression["subExpression"], caller_context)
         else:
+            attributes = expression["attributes"]
             assert len(expression["children"]) == 1
             expression = parse_expression(expression["children"][0], caller_context)
+        assert "prefix" in attributes
+
+        # Use of user defined operation
+        if "function" in attributes:
+            return _user_defined_op_call(
+                caller_context,
+                src,
+                attributes["function"],
+                [expression],
+                attributes["typeDescriptions"]["typeString"],
+            )
+
+        operation_type = UnaryOperationType.get_type(attributes["operator"], attributes["prefix"])
         unary_op = UnaryOperation(expression, operation_type)
         unary_op.set_offset(src, caller_context.compilation_unit)
         return unary_op
 
     if name == "BinaryOperation":
         if is_compact_ast:
             attributes = expression
-        else:
-            attributes = expression["attributes"]
-        operation_type = BinaryOperationType.get_type(attributes["operator"])
-
-        if is_compact_ast:
             left_expression = parse_expression(expression["leftExpression"], caller_context)
             right_expression = parse_expression(expression["rightExpression"], caller_context)
         else:
             assert len(expression["children"]) == 2
+            attributes = expression["attributes"]
             left_expression = parse_expression(expression["children"][0], caller_context)
             right_expression = parse_expression(expression["children"][1], caller_context)
+
+        # Use of user defined operation
+        if "function" in attributes:
+            return _user_defined_op_call(
+                caller_context,
+                src,
+                attributes["function"],
+                [left_expression, right_expression],
+                attributes["typeDescriptions"]["typeString"],
+            )
+
+        operation_type = BinaryOperationType.get_type(attributes["operator"])
         binary_op = BinaryOperation(left_expression, right_expression, operation_type)
         binary_op.set_offset(src, caller_context.compilation_unit)
         return binary_op

tests/e2e/solc_parsing/test_ast_parsing.py

@@ -458,6 +458,7 @@ def make_version(minor: int, patch_min: int, patch_max: int) -> List[str]:
         "assembly-functions.sol",
         ["0.6.9", "0.7.6", "0.8.16"],
     ),
+    Test("user_defined_operators-0.8.19.sol", ["0.8.19"]),
 ]
 # create the output folder if needed
 try:

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

@@ -0,0 +1,13 @@
+{
+  "Lib": {
+    "f(Int)": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n}\n"
+  },
+  "T": {
+    "add_function_call(Int,Int)": "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: RETURN 2\n\"];\n}\n",
+    "add_op(Int,Int)": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n",
+    "lib_call(Int)": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n",
+    "neg_usertype(Int)": "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: RETURN 2\n\"];\n}\n",
+    "neg_int(int256)": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n",
+    "eq_op(Int,Int)": "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/user_defined_operators-0.8.19.sol

@@ -0,0 +1,48 @@
+pragma solidity ^0.8.19;
+
+type Int is int;
+using {add as +, eq as ==, add, neg as -, Lib.f} for Int global;
+
+function add(Int a, Int b) pure returns (Int) {
+    return Int.wrap(Int.unwrap(a) + Int.unwrap(b));
+}
+
+function eq(Int a, Int b) pure returns (bool) {
+    return true;
+}
+
+function neg(Int a) pure returns (Int) {
+    return a;
+}
+
+library Lib {
+    function f(Int r) internal {}
+}
+
+contract T {
+    function add_function_call(Int b, Int c) public returns(Int) {
+        Int res = add(b,c);
+        return res;
+    }
+
+    function add_op(Int b, Int c) public returns(Int) {
+        return b + c;
+    }
+
+    function lib_call(Int b) public {
+        return b.f();
+    }
+
+    function neg_usertype(Int b) public returns(Int) {
+        Int res = -b;
+        return res;
+    }
+
+    function neg_int(int b) public returns(int) {
+        return -b;
+    }
+
+    function eq_op(Int b, Int c) public returns(bool) {
+        return b == c;
+    }
+}