Tracking: support for imports with alias (either symbol alias or unit alias)

[SheldonHolmgren]

Describe the issue:

See the linked repo with a minimal reproducible example. Running slither . --compile-force-framework foundry leads to the crash with a backtrace pasted as the log output below. This is because Slither cannot find a contract named c.Counter (as referenced from src/Importer.sol).

If I edit Importer.sol in the following way:

diff --git a/src/Importer.sol b/src/Importer.sol
index 316a7e3..5fbc2fe 100644
--- a/src/Importer.sol
+++ b/src/Importer.sol
@@ -2,10 +2,10 @@
 // SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.13;
 
-import "src/Counter.sol" as c;
+import "src/Counter.sol";
 
 contract Importer {
     constructor() {
-        new c.Counter();
+        new Counter();
     }
 }

slither runs without problem.

Code example to reproduce the issue:

https://github.com/SheldonHolmgren/slither_bug_example

Version:

0.9.0

Relevant log output:

'forge build --extra-output abi --extra-output userdoc --extra-output devdoc --extra-output evm.methodIdentifiers --force' running
Compiling 19 files with 0.8.16
Solc 0.8.16 finished in 1.52s
Compiler run successful

Traceback (most recent call last):
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/__main__.py", line 826, in main_impl
    ) = process_all(filename, args, detector_classes, printer_classes)
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/__main__.py", line 97, in process_all
    ) = process_single(compilation, args, detector_classes, printer_classes)
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/__main__.py", line 75, in process_single
    slither = Slither(target, ast_format=ast, **vars(args))
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/slither.py", line 130, in __init__
    parser.analyze_contracts()
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/solc_parsing/slither_compilation_unit_solc.py", line 503, in analyze_contracts
    self._convert_to_slithir()
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/solc_parsing/slither_compilation_unit_solc.py", line 688, in _convert_to_slithir
    func.generate_slithir_and_analyze()
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/core/declarations/function.py", line 1705, in generate_slithir_and_analyze
    node.slithir_generation()
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/core/cfg/node.py", line 719, in slithir_generation
    self._irs = convert_expression(expression, self)
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/slithir/convert.py", line 119, in convert_expression
    result = apply_ir_heuristics(result, node)
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/slithir/convert.py", line 1790, in apply_ir_heuristics
    irs = propagate_type_and_convert_call(irs, node)
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/slithir/convert.py", line 438, in propagate_type_and_convert_call
    new_ins = propagate_types(ins, node)
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/slithir/convert.py", line 743, in propagate_types
    ir.lvalue.set_type(UserDefinedType(contract))
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/core/solidity_types/user_defined_type.py", line 24, in __init__
    assert isinstance(t, (Contract, Enum, Structure))
AssertionError
Error in .
Traceback (most recent call last):
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/__main__.py", line 826, in main_impl
    ) = process_all(filename, args, detector_classes, printer_classes)
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/__main__.py", line 97, in process_all
    ) = process_single(compilation, args, detector_classes, printer_classes)
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/__main__.py", line 75, in process_single
    slither = Slither(target, ast_format=ast, **vars(args))
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/slither.py", line 130, in __init__
    parser.analyze_contracts()
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/solc_parsing/slither_compilation_unit_solc.py", line 503, in analyze_contracts
    self._convert_to_slithir()
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/solc_parsing/slither_compilation_unit_solc.py", line 688, in _convert_to_slithir
    func.generate_slithir_and_analyze()
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/core/declarations/function.py", line 1705, in generate_slithir_and_analyze
    node.slithir_generation()
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/core/cfg/node.py", line 719, in slithir_generation
    self._irs = convert_expression(expression, self)
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/slithir/convert.py", line 119, in convert_expression
    result = apply_ir_heuristics(result, node)
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/slithir/convert.py", line 1790, in apply_ir_heuristics
    irs = propagate_type_and_convert_call(irs, node)
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/slithir/convert.py", line 438, in propagate_type_and_convert_call
    new_ins = propagate_types(ins, node)
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/slithir/convert.py", line 743, in propagate_types
    ir.lvalue.set_type(UserDefinedType(contract))
  File "/home/holmgren/.local/lib/python3.10/site-packages/slither/core/solidity_types/user_defined_type.py", line 24, in __init__
    assert isinstance(t, (Contract, Enum, Structure))
AssertionError

[0xalpharush]

Thanks for creating a repo for reproducing this. We also need to address #1364

[0xalpharush]

Example from here #1536 (comment)

[0xalpharush]

• [Bug-Candidate]: Missing IRs after usage of aliased-imported-library-type array. #1634
• AssertionError when setting type for UserDefinedType #1594
• [Bug-Candidate]: AssertionError in ssa.py #1372
• Import with alias collision #1364
• [Bug]: Type Not Found #1874
• [Bug]: Infinite loop in SlitherCompilationUnitSolc._analyze_all_enums #1758

[0xalpharush]

somewhat related #1809

[singhpreetileo90]

Made certain changes to address the issue :

Changes to solc_parsing/declarations/convert.py : still getting error -

ERROR:ContractSolcParsing:Impossible to generate IR for Importer.constructor (Importer.sol#9-12):
'NoneType' object has no attribute 'references'

# Provide an additional function for handling 'import ... as ...' 
def parse_import_alias(self, stmt):
    import_alias_node = ast.AST.ImportAlias()
    import_alias_node.name = stmt['name']
    import_alias_node.alias = stmt['alias']
    return import_alias_node

# Use the new function parse_import to check for the 'as' keyword
def parse_import(self, stmt):
    import_node = ast.AST.Import()
    import_node.path = stmt['path']
    if 'as' in stmt:
        import_node.alias = self.parse_import_alias(stmt['as'])
    return import_node

[0xAurelou]

Any work on going on this PR ?

[0xalpharush]

Some work was started here but it is a large undertaking to get right and requires more testing #2250

[0xalpharush]

closed by #2403