AssertionError when setting type for UserDefinedType

[FredCoen]

Describe the issue:

After installing the latest slither version 0.9.2 I try to run slither . against my foundry project. unfrotunately I get the following trace below. Unfortunately the repo is currently closed source. Can I provide any more information?

Code example to reproduce the issue:
its a pretty standard foundry repo that cant be shared currently

Version:
0.9.2

Relevant log output:

'forge clean' running (wd: /Users/friedrichcoen/priv-contracts-v2)
'forge build --build-info --force' running
Compiling 196 files with 0.8.13
Solc 0.8.13 finished in 64.61s
Compiler run successful
Traceback (most recent call last):
  File "/opt/homebrew/lib/python3.9/site-packages/slither/__main__.py", line 834, in main_impl
    ) = process_all(filename, args, detector_classes, printer_classes)
  File "/opt/homebrew/lib/python3.9/site-packages/slither/__main__.py", line 98, in process_all
    ) = process_single(compilation, args, detector_classes, printer_classes)
  File "/opt/homebrew/lib/python3.9/site-packages/slither/__main__.py", line 76, in process_single
    slither = Slither(target, ast_format=ast, **vars(args))
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slither.py", line 133, in init
    self._init_parsing_and_analyses(kwargs.get("skip_analyze", False))
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slither.py", line 153, in _init_parsing_and_analyses
    raise e
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slither.py", line 149, in _init_parsing_and_analyses
    parser.analyze_contracts()
  File "/opt/homebrew/lib/python3.9/site-packages/slither/solc_parsing/slither_compilation_unit_solc.py", line 529, in analyze_contracts
    self._convert_to_slithir()
  File "/opt/homebrew/lib/python3.9/site-packages/slither/solc_parsing/slither_compilation_unit_solc.py", line 740, in _convert_to_slithir
    func.generate_slithir_and_analyze()
  File "/opt/homebrew/lib/python3.9/site-packages/slither/core/declarations/function.py", line 1750, in generate_slithir_and_analyze
    node.slithir_generation()
  File "/opt/homebrew/lib/python3.9/site-packages/slither/core/cfg/node.py", line 719, in slithir_generation
    self._irs = convert_expression(expression, self)
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slithir/convert.py", line 119, in convert_expression
    result = apply_ir_heuristics(result, node)
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slithir/convert.py", line 1858, in apply_ir_heuristics
    irs = propagate_type_and_convert_call(irs, node)
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slithir/convert.py", line 442, in propagate_type_and_convert_call
    new_ins = propagate_types(ins, node)
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slithir/convert.py", line 774, in propagate_types
    ir.lvalue.set_type(UserDefinedType(contract))
  File "/opt/homebrew/lib/python3.9/site-packages/slither/core/solidity_types/user_defined_type.py", line 19, in init
    assert isinstance(t, (Contract, Enum, Structure))
AssertionError
Error in .
Traceback (most recent call last):
  File "/opt/homebrew/lib/python3.9/site-packages/slither/__main__.py", line 834, in main_impl
    ) = process_all(filename, args, detector_classes, printer_classes)
  File "/opt/homebrew/lib/python3.9/site-packages/slither/__main__.py", line 98, in process_all
    ) = process_single(compilation, args, detector_classes, printer_classes)
  File "/opt/homebrew/lib/python3.9/site-packages/slither/__main__.py", line 76, in process_single
    slither = Slither(target, ast_format=ast, **vars(args))
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slither.py", line 133, in init
    self._init_parsing_and_analyses(kwargs.get("skip_analyze", False))
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slither.py", line 153, in _init_parsing_and_analyses
    raise e
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slither.py", line 149, in _init_parsing_and_analyses
    parser.analyze_contracts()
  File "/opt/homebrew/lib/python3.9/site-packages/slither/solc_parsing/slither_compilation_unit_solc.py", line 529, in analyze_contracts
    self._convert_to_slithir()
  File "/opt/homebrew/lib/python3.9/site-packages/slither/solc_parsing/slither_compilation_unit_solc.py", line 740, in _convert_to_slithir
    func.generate_slithir_and_analyze()
  File "/opt/homebrew/lib/python3.9/site-packages/slither/core/declarations/function.py", line 1750, in generate_slithir_and_analyze
    node.slithir_generation()
  File "/opt/homebrew/lib/python3.9/site-packages/slither/core/cfg/node.py", line 719, in slithir_generation

self._irs = convert_expression(expression, self)
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slithir/convert.py", line 119, in convert_expression
    result = apply_ir_heuristics(result, node)
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slithir/convert.py", line 1858, in apply_ir_heuristics
    irs = propagate_type_and_convert_call(irs, node)
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slithir/convert.py", line 442, in propagate_type_and_convert_call
    new_ins = propagate_types(ins, node)
  File "/opt/homebrew/lib/python3.9/site-packages/slither/slithir/convert.py", line 774, in propagate_types
    ir.lvalue.set_type(UserDefinedType(contract))
  File "/opt/homebrew/lib/python3.9/site-packages/slither/core/solidity_types/user_defined_type.py", line 19, in init
    assert isinstance(t, (Contract, Enum, Structure))
AssertionError

[0xalpharush]

Hey Fred, we chatted on telegram. Just leaving some notes... get_contract_from_name can return None, but that may mean something is off with scoping here... we will need to reproduce.

slither/slither/slithir/convert.py

Lines 772 to 774 in 4c976d5

	elif isinstance(ir, NewContract):
	contract = node.file_scope.get_contract_from_name(ir.contract_name)
	ir.lvalue.set_type(UserDefinedType(contract))

[0xalpharush]

This is related to something like:

import {MyContract as MyAliasedContract} from "./MyContract.sol";

contract Test {
MyAliasedContract c;
    constructor {
        c = new MyAliasedContract();
    }
} 

I believe #1539 fixes this although I think we could improve alias support more broadly with a different approach than is currently implemented in Slither

[singhpreetileo90]

Leaving some notes for #1594 and #1452 - I tried handling the the possibility of an AssertionError being raised during the creation of the user_defined_type object using try and except statement. and then I performed type checking and alias resolution on the t object as well as alias resolution for a given alias object and module as follows :

from typing import Union, TYPE_CHECKING, Tuple
import math
import ast
from slither.core.solidity_types.type import Type
from slither.exceptions import SlitherException
if TYPE_CHECKING:
from slither.core.declarations.structure import Structure
from slither.core.declarations.enum import Enum
from slither.core.declarations.contract import Contract

pylint: disable=import-outside-toplevel

class UserDefinedType(Type):
def init(self, t):
from slither.core.declarations.structure import Structure
from slither.core.declarations.enum import Enum
from slither.core.declarations.contract import Contract

    #assert isinstance(t, (Contract, Enum, Structure))
    #super().__init__()

    #handle the possibility of an 'AssertionError'
    try:
        class MyUserDefinedType(UserDefinedType):
            def __init__(self, x):
                if isinstance(x, (Contract, Enum, Structure)):
                    super().__init__(x)
                else:
                    self.x = t

        user_defined_type = MyUserDefinedType(t)

    except AssertionError:
        # Handle the error
        user_defined_type = None
    
    # Check if the given type is an alias
    type_check = str
    if hasattr(t, "name") and isinstance(t.name, type_check):
        print(t)
        alias_name = t.name
        for compilation_unit in t.contract.compilation_units:
            module = t.contract.resolver.resolve_unit(compilation_unit)
            alias = module.get_alias(alias_name)
            if alias is not None:
                t = alias.name

    print(f"t: {t}")
    self._type = t

@staticmethod
def alias_check(alias, module):
    if alias is None:
        return None

    if isinstance(alias, ast.Alias) and alias.kind == 'contract':
       instance = module.get_contract(alias.name)
    elif isinstance(alias, ast.Alias) and alias.kind == 'enum':
       instance = module.get_enum(alias.name)
    elif isinstance(alias, ast.Alias) and alias.kind == 'structure':
       instance = module.get_structure(alias.name)
    else:
       return None

    if instance is None:
       return None

    if isinstance(instance, ast.Alias):
       return UserDefinedType.alias_check(instance.alias, module)
    return instance.name

The output is :
t: None
Impossible to generate IR for Importer.constructor (Importer.sol#8-10):
'NoneType' object has no attribute 'references'