AssertionError in resolve_remapping_and_renaming when analyzing contract with import aliasing

[Aniket-Engg]

Description

Slither fails with an AssertionError when analyzing Solidity code that imports files using import aliasing (specifically the Chainlink KeeperCompatibleInterface.sol pattern).

Environment

• Slither version: 0.11.5
• Python version: 3.11
• Operating system: macOS (Darwin 22.3.0)
• Solidity compiler: 0.8.34
• Framework: Foundry

Steps to Reproduce

1. Create a Foundry project with the following structure:

foundry.toml:

[profile.default]
src = "src"
out = "out"
libs = ["lib"]

remappings.txt:

  @chainlink/=lib/chainlink-evm/

src/KeepersCounter.sol:

  // SPDX-License-Identifier: MIT
  pragma solidity ^0.8.0;

  import "@chainlink/contracts/src/v0.8/automation/interfaces/KeeperCompatibleInterface.sol";

  contract KeepersCounter is KeeperCompatibleInterface {
      uint256 public counter;
      uint256 public immutable interval;
      uint256 public lastTimeStamp;

      constructor(uint256 updateInterval) {
          interval = updateInterval;
          lastTimeStamp = block.timestamp;
          counter = 0;
      }

      function checkUpkeep(bytes calldata) external view override returns (bool upkeepNeeded, bytes memory) {
          upkeepNeeded = (block.timestamp - lastTimeStamp) > interval;
      }

      function performUpkeep(bytes calldata) external override {
          if ((block.timestamp - lastTimeStamp) > interval) {
              lastTimeStamp = block.timestamp;
              counter = counter + 1;
          }
      }
  }

lib/chainlink-evm/contracts/src/v0.8/automation/interfaces/KeeperCompatibleInterface.sol:

  // SPDX-License-Identifier: MIT
  pragma solidity ^0.8.0;

  import {AutomationCompatibleInterface as KeeperCompatibleInterface} from "./AutomationCompatibleInterface.sol";

  lib/chainlink-evm/contracts/src/v0.8/automation/interfaces/AutomationCompatibleInterface.sol:
  // SPDX-License-Identifier: MIT
  pragma solidity ^0.8.0;

  interface AutomationCompatibleInterface {
      function checkUpkeep(bytes calldata checkData) external returns (bool upkeepNeeded, bytes memory performData);
      function performUpkeep(bytes calldata performData) external;
  }

2. Run: forge build (this succeeds)
3. Run: slither .

Expected Behavior

Slither should successfully analyze the contract.

Actual Behavior

Slither fails with:

Traceback (most recent call last):
File "/opt/homebrew/bin/slither", line 8, in
sys.exit(main())
^^^^^^
File "/opt/homebrew/lib/python3.11/site-packages/slither/main.py", line 760, in main
main_impl(all_detector_classes=detectors, all_printer_classes=printers)
File "/opt/homebrew/lib/python3.11/site-packages/slither/main.py", line 865, in main_impl
) = process_all(filename, args, detector_classes, printer_classes)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/lib/python3.11/site-packages/slither/main.py", line 106, in process_all
) = process_single(compilation, args, detector_classes, printer_classes)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/lib/python3.11/site-packages/slither/main.py", line 79, in process_single
slither = Slither(target, ast_format=ast, **vars(args))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/lib/python3.11/site-packages/slither/slither.py", line 197, in init
self._init_parsing_and_analyses(kwargs.get("skip_analyze", False))
File "/opt/homebrew/lib/python3.11/site-packages/slither/slither.py", line 206, in _init_parsing_and_analyses
raise e
File "/opt/homebrew/lib/python3.11/site-packages/slither/slither.py", line 202, in _init_parsing_and_analyses
parser.parse_contracts()
File "/opt/homebrew/lib/python3.11/site-packages/slither/solc_parsing/slither_compilation_unit_solc.py", line 502, in parse_contracts
target = resolve_remapping_and_renaming(contract_parser, i)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/lib/python3.11/site-packages/slither/solc_parsing/slither_compilation_unit_solc.py", line 488, in resolve_remapping_and_renaming
assert target, f"Contract {contract_name} not found"
AssertionError: Contract KeeperCompatibleInterface not found

---

Trying slither with --ignore-compile and running forge build --ast before hand throws these errors:

  File "/opt/homebrew/lib/python3.11/site-packages/crytic_compile/crytic_compile.py", line 211, in __init__
    self._compile(**kwargs)
  File "/opt/homebrew/lib/python3.11/site-packages/crytic_compile/crytic_compile.py", line 633, in _compile
    self._platform.compile(self, **kwargs)
  File "/opt/homebrew/lib/python3.11/site-packages/crytic_compile/platform/foundry.py", line 102, in compile
    hardhat_like_parsing(
  File "/opt/homebrew/lib/python3.11/site-packages/crytic_compile/platform/hardhat.py", line 72, in hardhat_like_parsing
    targets_json = loaded_json["output"]
                   ~~~~~~~~~~~^^^^^^^^^^
KeyError: 'output'

Root Cause

The issue occurs in slither_compilation_unit_solc.py:488 in the resolve_remapping_and_renaming function. The file KeeperCompatibleInterface.sol uses the pattern:

import {AutomationCompatibleInterface as KeeperCompatibleInterface} from "./AutomationCompatibleInterface.sol";

This creates an alias/re-export where KeeperCompatibleInterface is not actually defined as a contract in the file, but is aliased from AutomationCompatibleInterface. Slither's contract resolver cannot find
KeeperCompatibleInterface as an actual contract definition and fails.

Additional Context

• The same code compiles successfully with forge build
• This is a legitimate Solidity pattern used in production (Chainlink contracts)
• Flags tried without success: --foundry-compile-all, --foundry-ignore-compile, --foundry-out-directory
• Related to issue Tracking: support for imports with alias (either symbol alias or unit alias) #1452 about import aliasing support

[ChargingFoxSec]

I can reproduce this on current master.

I found that inheritance resolution falls back to the current file scope, but does not continue through accessible imported scopes when the inherited name is a re-exported import alias.

I have a small regression test and fix locally. I’ll open a PR if this direction looks reasonable.