Merge pull request #215 from crytic/dev-fp-erc20-interface

Fix FP in erc20-interface as a result of ERC721 similarities
6 years ago · f0cb66dd2b
parent 0fd77f9042 1d4d681e2c
commit f0cb66dd2b
34 changed files with 1407 additions and 53 deletions
--- a/README.md
+++ b/README.md
@ -71,6 +71,7 @@ Num | Detector | What it Detects | Impact | Confidence
 30 | `pragma` | [If different pragma directives are used](https://github.com/crytic/slither/wiki/Detector-Documentation#different-pragma-directives-are-used) | Informational | High
 31 | `solc-version` | [Incorrect Solidity version (< 0.4.24 or complex pragma)](https://github.com/crytic/slither/wiki/Detector-Documentation#incorrect-version-of-solidity) | Informational | High
 32 | `unused-state` | [Unused state variables](https://github.com/crytic/slither/wiki/Detector-Documentation#unused-state-variables) | Informational | High
+33 | `too-many-digits` | [Conformance to numeric notation best practices](https://github.com/crytic/slither/wiki/Detector-Documentation#too-many-digits) | Informational | Medium

 [Contact us](https://www.trailofbits.com/contact/) to get access to additional detectors.

--- a/scripts/tests_generate_expected_json_4.sh
+++ b/scripts/tests_generate_expected_json_4.sh
@ -23,6 +23,7 @@ generate_expected_json(){
 #generate_expected_json tests/deprecated_calls.sol "deprecated-standards"
 #generate_expected_json tests/erc20_indexed.sol "erc20-indexed"
 #generate_expected_json tests/incorrect_erc20_interface.sol "erc20-interface"
+#generate_expected_json tests/incorrect_erc721_interface.sol "erc721-interface"
 #generate_expected_json tests/uninitialized.sol "uninitialized-state"
 #generate_expected_json tests/backdoor.sol "backdoor"
 #generate_expected_json tests/backdoor.sol "suicidal"
--- a/scripts/tests_generate_expected_json_5.sh
+++ b/scripts/tests_generate_expected_json_5.sh
@ -19,18 +19,20 @@ generate_expected_json(){
    sed "s|$CURRENT_PATH|$TRAVIS_PATH|g" "$output_filename" -i
 }

-generate_expected_json tests/uninitialized-0.5.1.sol "uninitialized-state"
-generate_expected_json tests/backdoor.sol "backdoor"
-generate_expected_json tests/backdoor.sol "suicidal"
-generate_expected_json tests/pragma.0.4.24.sol "pragma"
-generate_expected_json tests/old_solc.sol.json "solc-version"
-generate_expected_json tests/reentrancy-0.5.1.sol "reentrancy-eth"
-generate_expected_json tests/reentrancy-0.5.1.sol "reentrancy"
-generate_expected_json tests/uninitialized_storage_pointer.sol "uninitialized-storage"
-generate_expected_json tests/tx_origin-0.5.1.sol "tx-origin"
-generate_expected_json tests/locked_ether-0.5.1.sol "locked-ether"
-generate_expected_json tests/arbitrary_send-0.5.1.sol "arbitrary-send"
-generate_expected_json tests/inline_assembly_contract-0.5.1.sol "assembly"
-generate_expected_json tests/inline_assembly_library-0.5.1.sol "assembly"
-generate_expected_json tests/constant-0.5.1.sol "constant-function"
-generate_expected_json tests/incorrect_equality.sol "incorrect-equality"
+#generate_expected_json tests/uninitialized-0.5.1.sol "uninitialized-state"
+#generate_expected_json tests/backdoor.sol "backdoor"
+#generate_expected_json tests/backdoor.sol "suicidal"
+#generate_expected_json tests/pragma.0.4.24.sol "pragma"
+#generate_expected_json tests/old_solc.sol.json "solc-version"
+#generate_expected_json tests/reentrancy-0.5.1.sol "reentrancy-eth"
+#generate_expected_json tests/reentrancy-0.5.1.sol "reentrancy"
+#generate_expected_json tests/uninitialized_storage_pointer.sol "uninitialized-storage"
+#generate_expected_json tests/tx_origin-0.5.1.sol "tx-origin"
+#generate_expected_json tests/locked_ether-0.5.1.sol "locked-ether"
+#generate_expected_json tests/arbitrary_send-0.5.1.sol "arbitrary-send"
+#generate_expected_json tests/inline_assembly_contract-0.5.1.sol "assembly"
+#generate_expected_json tests/inline_assembly_library-0.5.1.sol "assembly"
+#generate_expected_json tests/constant-0.5.1.sol "constant-function"
+#generate_expected_json tests/incorrect_equality.sol "incorrect-equality"
+#generate_expected_json tests/too_many_digits.sol "too-many-digits"
+
--- a/scripts/travis_test_4.sh
+++ b/scripts/travis_test_4.sh
@ -72,6 +72,7 @@ test_slither(){
 test_slither tests/deprecated_calls.sol "deprecated-standards"
 test_slither tests/erc20_indexed.sol "erc20-indexed"
 test_slither tests/incorrect_erc20_interface.sol "erc20-interface"
+test_slither tests/incorrect_erc721_interface.sol "erc721-interface"
 test_slither tests/uninitialized.sol "uninitialized-state"
 test_slither tests/backdoor.sol "backdoor"
 test_slither tests/backdoor.sol "suicidal"
--- a/scripts/travis_test_5.sh
+++ b/scripts/travis_test_5.sh
@ -91,6 +91,8 @@ test_slither tests/constant-0.5.1.sol "constant-function"
 test_slither tests/unused_return.sol "unused-return"
 test_slither tests/timestamp.sol "timestamp"
 test_slither tests/incorrect_equality.sol "incorrect-equality"
+test_slither tests/too_many_digits.sol "too-many-digits"
+

 ### Test scripts

--- a/slither/core/declarations/contract.py
+++ b/slither/core/declarations/contract.py
@ -527,6 +527,14 @@ class Contract(ChildSlither, SourceMapping):
        """
        return all((not f.is_implemented) for f in self.functions)

+    # endregion
+    ###################################################################################
+    ###################################################################################
+    # region ERC conformance
+    ###################################################################################
+    ###################################################################################
+
+
    def is_erc20(self):
        """
            Check if the contract is an erc20 token
@ -535,11 +543,49 @@ class Contract(ChildSlither, SourceMapping):
        Returns:
            bool
        """
-        full_names = [f.full_name for f in self.functions]
+        full_names = set([f.full_name for f in self.functions])
        return 'transfer(address,uint256)' in full_names and\
               'transferFrom(address,address,uint256)' in full_names and\
               'approve(address,uint256)' in full_names

+    def is_erc721(self):
+        full_names = set([f.full_name for f in self.functions])
+        return self.is_erc20() and\
+               'ownerOf(uint256)' in full_names and\
+               'safeTransferFrom(address,address,uint256,bytes)' in full_names and\
+               'safeTransferFrom(address,address,uint256)' in full_names and\
+               'setApprovalForAll(address,bool)' in full_names and\
+               'getApproved(uint256)' in full_names and\
+               'isApprovedForAll(address,address)' in full_names
+
+    def has_an_erc20_function(self):
+        """
+        Checks if the provided contract could be attempting to implement ERC20 standards.
+        :param contract: The contract to check for token compatibility.
+        :return: Returns a boolean indicating if the provided contract met the token standard.
+        """
+        full_names = set([f.full_name for f in self.functions])
+        return 'transfer(address,uint256)' in full_names or \
+               'transferFrom(address,address,uint256)' in full_names or \
+               'approve(address,uint256)' in full_names
+
+    def has_an_erc721_function(self):
+        """
+        Checks if the provided contract could be attempting to implement ERC721 standards.
+        :param contract: The contract to check for token compatibility.
+        :return: Returns a boolean indicating if the provided contract met the token standard.
+        """
+        full_names = set([f.full_name for f in self.functions])
+        return self.has_an_erc20_function() and \
+               ('ownerOf(uint256)' in full_names or
+                'safeTransferFrom(address,address,uint256,bytes)' in full_names or
+                'safeTransferFrom(address,address,uint256)' in full_names or
+                'setApprovalForAll(address,bool)' in full_names or
+                'getApproved(uint256)' in full_names or
+                'isApprovedForAll(address,address)' in full_names)
+
+
+
    # endregion
    ###################################################################################
    ###################################################################################
--- a/slither/core/declarations/function.py
+++ b/slither/core/declarations/function.py
@ -86,6 +86,7 @@ class Function(ChildContract, SourceMapping):
        self._reachable_from_nodes = set()
        self._reachable_from_functions = set()

+
    ###################################################################################
    ###################################################################################
    # region General properties
@ -1070,4 +1071,4 @@ class Function(ChildContract, SourceMapping):
    def __str__(self):
        return self._name

-    # endregion
+    # endregion
--- a/slither/core/declarations/structure.py
+++ b/slither/core/declarations/structure.py
@ -10,6 +10,8 @@ class Structure(ChildContract, SourceMapping):
        self._name = None
        self._canonical_name = None
        self._elems = None
+        # Name of the elements in the order of declaration
+        self._elems_ordered = None

    @property
    def canonical_name(self):
@ -23,5 +25,12 @@ class Structure(ChildContract, SourceMapping):
    def elems(self):
        return self._elems

+    @property
+    def elems_ordered(self):
+        ret = []
+        for e in self._elems_ordered:
+            ret.append(self._elems[e])
+        return ret
+
    def __str__(self):
        return self.name
--- a/slither/core/expressions/literal.py
+++ b/slither/core/expressions/literal.py
@ -2,14 +2,19 @@ from slither.core.expressions.expression import Expression

 class Literal(Expression):

-    def __init__(self, value):
+    def __init__(self, value, type):
        super(Literal, self).__init__()
        self._value = value
+        self._type = type

    @property
    def value(self):
        return self._value

+    @property
+    def type(self):
+        return self._type
+
    def __str__(self):
        # be sure to handle any character
        return str(self._value)
--- a/slither/core/solidity_types/array_type.py
+++ b/slither/core/solidity_types/array_type.py
@ -10,7 +10,7 @@ class ArrayType(Type):
        assert isinstance(t, Type)
        if length:
            if isinstance(length, int):
-                length = Literal(length)
+                length = Literal(length, 'uint256')
            assert isinstance(length, Expression)
        super(ArrayType, self).__init__()
        self._type = t
@ -18,7 +18,7 @@ class ArrayType(Type):

        if length:
            if not isinstance(length, Literal):
-                cf = ConstantFolding(length)
+                cf = ConstantFolding(length, "uint256")
                length = cf.result()
            self._length_value = length
        else:
--- a/slither/core/variables/state_variable.py
+++ b/slither/core/variables/state_variable.py
@ -3,7 +3,6 @@ from slither.core.children.child_contract import ChildContract

 class StateVariable(ChildContract, Variable):

-
    @property
    def canonical_name(self):
        return '{}:{}'.format(self.contract.name, self.name)
--- a/slither/detectors/all_detectors.py
+++ b/slither/detectors/all_detectors.py
@ -28,9 +28,11 @@ from .shadowing.builtin_symbols import BuiltinSymbolShadowing
 from .operations.block_timestamp import Timestamp
 from .statements.calls_in_loop import MultipleCallsInLoop
 from .statements.incorrect_strict_equality import IncorrectStrictEquality
-from .erc20.incorrect_interface import IncorrectERC20InterfaceDetection
-from .erc20.unindexed_event_parameters import UnindexedERC20EventParameters
+from .erc.incorrect_erc20_interface import IncorrectERC20InterfaceDetection
+from .erc.incorrect_erc721_interface import IncorrectERC721InterfaceDetection
+from .erc.unindexed_event_parameters import UnindexedERC20EventParameters
 from .statements.deprecated_calls import DeprecatedStandards
 from .source.rtlo import RightToLeftOverride
+from .statements.too_many_digits import TooManyDigits
 #
 #
--- a/slither/detectors/erc20/init.py
+++ b/slither/detectors/erc20/init.py
--- a/slither/detectors/erc/incorrect_erc20_interface.py
+++ b/slither/detectors/erc/incorrect_erc20_interface.py
@ -18,7 +18,7 @@ class IncorrectERC20InterfaceDetection(AbstractDetector):
    WIKI = 'https://github.com/crytic/slither/wiki/Detector-Documentation#incorrect-erc20-interface'

    WIKI_TITLE = 'Incorrect erc20 interface'
-    WIKI_DESCRIPTION = 'Lack of return value for the ERC20 `approve`/`transfer`/`transferFrom` functions. A contract compiled with solidity > 0.4.22 interacting with these functions will fail to execute them, as the return value is missing.'
+    WIKI_DESCRIPTION = 'Incorrect return values for ERC20 functions. A contract compiled with solidity > 0.4.22 interacting with these functions will fail to execute them, as the return value is missing.'
    WIKI_EXPLOIT_SCENARIO = '''
 ```solidity
 contract Token{
@ -28,7 +28,7 @@ contract Token{
 ```
 `Token.transfer` does not return a boolean. Bob deploys the token. Alice creates a contract that interacts with it but assumes a correct ERC20 interface implementation. Alice's contract is unable to interact with Bob's contract.'''

-    WIKI_RECOMMENDATION = 'Return a boolean for the `approve`/`transfer`/`transferFrom` functions.'
+    WIKI_RECOMMENDATION = 'Set the appropriate return values and value-types for the defined ERC20 functions.'

    @staticmethod
    def incorrect_erc20_interface(signature):
@ -43,6 +43,15 @@ contract Token{
        if name == 'approve' and parameters == ['address', 'uint256'] and returnVars != ['bool']:
            return True

+        if name == 'allowance' and parameters == ['address', 'address'] and returnVars != ['uint256']:
+            return True
+
+        if name == 'balanceOf' and parameters == ['address'] and returnVars != ['uint256']:
+            return True
+
+        if name == 'totalSupply' and parameters == [] and returnVars != ['uint256']:
+            return True
+
        return False

    @staticmethod
@ -52,15 +61,23 @@ contract Token{
        Returns:
            list(str) : list of incorrect function signatures
        """
-        functions = [f for f in contract.functions if f.contract == contract and \
-                     IncorrectERC20InterfaceDetection.incorrect_erc20_interface(f.signature)]
+        # Verify this is an ERC20 contract.
+        if not contract.has_an_erc20_function():
+            return []
+
+        # If this contract implements a function from ERC721, we can assume it is an ERC721 token. These tokens
+        # offer functions which are similar to ERC20, but are not compatible.
+        if contract.has_an_erc721_function():
+            return []
+
+        functions = [f for f in contract.functions if IncorrectERC20InterfaceDetection.incorrect_erc20_interface(f.signature)]
        return functions

    def _detect(self):
        """ Detect incorrect erc20 interface

        Returns:
-            dict: [contrat name] = set(str)  events
+            dict: [contract name] = set(str)  events
        """
        results = []
        for c in self.contracts:
--- a/slither/detectors/erc/incorrect_erc721_interface.py
+++ b/slither/detectors/erc/incorrect_erc721_interface.py
@ -0,0 +1,96 @@
+"""
+Detect incorrect erc721 interface.
+"""
+from slither.detectors.abstract_detector import AbstractDetector, DetectorClassification
+
+
+class IncorrectERC721InterfaceDetection(AbstractDetector):
+    """
+    Incorrect ERC721 Interface
+    """
+
+    ARGUMENT = 'erc721-interface'
+    HELP = 'Incorrect ERC721 interfaces'
+    IMPACT = DetectorClassification.MEDIUM
+    CONFIDENCE = DetectorClassification.HIGH
+
+    WIKI = 'https://github.com/crytic/slither/wiki/Detector-Documentation#incorrect-erc721-interface'
+
+    WIKI_TITLE = 'Incorrect erc721 interface'
+    WIKI_DESCRIPTION = 'Incorrect return values for ERC721 functions. A contract compiled with solidity > 0.4.22 interacting with these functions will fail to execute them, as the return value is missing.'
+    WIKI_EXPLOIT_SCENARIO = '''
+```solidity
+contract Token{
+    function ownerOf(uint256 _tokenId) external view returns (bool);
+    //...
+}
+```
+`Token.ownerOf` does not return an address as ERC721 expects. Bob deploys the token. Alice creates a contract that interacts with it but assumes a correct ERC721 interface implementation. Alice's contract is unable to interact with Bob's contract.'''
+
+    WIKI_RECOMMENDATION = 'Set the appropriate return values and value-types for the defined ERC721 functions.'
+
+    @staticmethod
+    def incorrect_erc721_interface(signature):
+        (name, parameters, returnVars) = signature
+
+        # ERC721
+        if name == 'balanceOf' and parameters == ['address'] and returnVars != ['uint256']:
+            return True
+        if name == 'ownerOf' and parameters == ['uint256'] and returnVars != ['address']:
+            return True
+        if name == 'safeTransferFrom' and parameters == ['address', 'address', 'uint256', 'bytes'] and returnVars != []:
+            return True
+        if name == 'safeTransferFrom' and parameters == ['address', 'address', 'uint256'] and returnVars != []:
+            return True
+        if name == 'transferFrom' and parameters == ['address', 'address', 'uint256'] and returnVars != []:
+            return True
+        if name == 'approve' and parameters == ['address', 'uint256'] and returnVars != []:
+            return True
+        if name == 'setApprovalForAll' and parameters == ['address', 'bool'] and returnVars != []:
+            return True
+        if name == 'getApproved' and parameters == ['uint256'] and returnVars != ['address']:
+            return True
+        if name == 'isApprovedForAll' and parameters == ['address', 'address'] and returnVars != ['bool']:
+            return True
+
+        # ERC165 (dependency)
+        if name == 'supportsInterface' and parameters == ['bytes4'] and returnVars != ['bool']:
+            return True
+
+        return False
+
+    @staticmethod
+    def detect_incorrect_erc721_interface(contract):
+        """ Detect incorrect ERC721 interface
+
+        Returns:
+            list(str) : list of incorrect function signatures
+        """
+
+        # Verify this is an ERC721 contract.
+        if not contract.has_an_erc721_function() or not contract.has_an_erc20_function():
+            return []
+
+        functions = [f for f in contract.functions if IncorrectERC721InterfaceDetection.incorrect_erc721_interface(f.signature)]
+        return functions
+
+    def _detect(self):
+        """ Detect incorrect erc721 interface
+
+        Returns:
+            dict: [contract name] = set(str)  events
+        """
+        results = []
+        for c in self.contracts:
+            functions = IncorrectERC721InterfaceDetection.detect_incorrect_erc721_interface(c)
+            if functions:
+                info = "{} ({}) has incorrect ERC721 function interface(s):\n"
+                info = info.format(c.name,
+                                   c.source_mapping_str)
+                for function in functions:
+                    info += "\t-{} ({})\n".format(function.name, function.source_mapping_str)
+                json = self.generate_json_result(info)
+                self.add_functions_to_json(functions, json)
+                results.append(json)
+
+        return results
--- a/slither/detectors/erc20/unindexed_event_parameters.py
+++ b/slither/detectors/erc20/unindexed_event_parameters.py
--- a/slither/detectors/statements/too_many_digits.py
+++ b/slither/detectors/statements/too_many_digits.py
@ -0,0 +1,80 @@
+"""
+Module detecting numbers with too many digits.
+"""
+
+from slither.detectors.abstract_detector import AbstractDetector, DetectorClassification
+from slither.slithir.variables import Constant
+
+class TooManyDigits(AbstractDetector):
+    """
+    Detect numbers with too many digits
+    """
+
+    ARGUMENT = 'too-many-digits'
+    HELP = 'Conformance to numeric notation best practices'
+    IMPACT = DetectorClassification.INFORMATIONAL
+    CONFIDENCE = DetectorClassification.MEDIUM
+
+    WIKI = 'https://github.com/crytic/slither/wiki/Detector-Documentation#too-many-digits'
+    WIKI_TITLE = 'Too many digits'
+    WIKI_DESCRIPTION = '''
+Literals with many digits are difficult to read and review.
+'''
+    WIKI_EXPLOIT_SCENARIO = '''
+```solidity
+contract MyContract{
+    uint 1_ether = 10000000000000000000; 
+}
+```
+
+While `1_ether` looks like `1 ether`, it is `10 ether`. As a result, its usage is likely to be incorrect.
+'''
+    WIKI_RECOMMENDATION = '''
+Use:
+- [Ether suffix](https://solidity.readthedocs.io/en/latest/units-and-global-variables.html#ether-units)
+- [Time suffix](https://solidity.readthedocs.io/en/latest/units-and-global-variables.html#time-units), or
+- [The scientific notation](https://solidity.readthedocs.io/en/latest/types.html#rational-and-integer-literals)
+'''
+
+    @staticmethod
+    def _detect_too_many_digits(f):
+        ret = []
+        for node in f.nodes:
+            # each node contains a list of IR instruction
+            for ir in node.irs:
+                # iterate over all the variables read by the IR
+                for read in ir.read:
+                    # if the variable is a constant
+                    if isinstance(read, Constant):
+                        # read.value can return an int or a str. Convert it to str
+                        value_as_str = read.original_value
+                        line_of_code = str(node.expression)
+                        if '00000' in value_as_str:
+                            # Info to be printed
+                            ret.append(node)
+        return ret
+
+    def _detect(self):
+        results = []
+
+        # iterate over all contracts
+        for contract in self.slither.contracts_derived:
+        # iterate over all functions
+            for f in contract.functions:
+                # iterate over all the nodes
+                ret = self._detect_too_many_digits(f)
+                if ret:
+                    info = '{}.{} ({}) uses literals with too many digits:'.format(f.contract.name,
+                                                                                   f.name,
+                                                                                   f.source_mapping_str)
+                    for node in ret:
+                        info += '\n\t- {}'.format(node.expression)
+                    info += '\n\tUse the proper denomination (ether-unit, time-unit,'
+                    info += 'or the scientific notation\n'
+
+                    # Add the result in result
+                    json = self.generate_json_result(info)
+                    self.add_nodes_to_json(ret, json)
+                    results.append(json)
+
+        return results
--- a/slither/slithir/convert.py
+++ b/slither/slithir/convert.py
@ -7,7 +7,9 @@ from slither.core.expressions import Identifier, Literal
 from slither.core.solidity_types import (ArrayType, ElementaryType,
                                         FunctionType, MappingType,
                                         UserDefinedType)
+from slither.core.solidity_types.elementary_type import Int as ElementaryTypeInt
 from slither.core.variables.variable import Variable
+from slither.core.variables.state_variable import StateVariable
 from slither.slithir.operations import (Assignment, Balance, Binary,
                                        BinaryType, Call, Condition, Delete,
                                        EventCall, HighLevelCall, Index,
@ -30,6 +32,7 @@ from slither.slithir.variables import (Constant, ReferenceVariable,
                                       TemporaryVariable)
 from slither.visitors.slithir.expression_to_slithir import ExpressionToSlithIR
 from slither.utils.function import get_function_id
+from slither.utils.type import export_nested_types_from_variable

 logger = logging.getLogger('ConvertToIR')

@ -39,7 +42,8 @@ def convert_expression(expression, node):
    from slither.core.cfg.node import NodeType

    if isinstance(expression, Literal) and node.type in [NodeType.IF, NodeType.IFLOOP]:
-        result =  [Condition(Constant(expression.value))]
+        cst = Constant(expression.value, expression.type)
+        result =  [Condition(cst)]
        return result
    if isinstance(expression, Identifier) and node.type in [NodeType.IF, NodeType.IFLOOP]:
        result =  [Condition(expression.value)]
@ -599,7 +603,7 @@ def convert_to_push(ir, node):

        ir = Push(ir.destination, val)

-        length = Literal(len(operation.init_values))
+        length = Literal(len(operation.init_values), 'uint256')
        t = operation.init_values[0].type
        ir.lvalue.set_type(ArrayType(t, length))

@ -822,6 +826,71 @@ def remove_unused(result):
        result = [i for i in result if not i in to_remove]
    return result

+# endregion
+###################################################################################
+###################################################################################
+# region Constant type conversioh
+###################################################################################
+###################################################################################
+
+def convert_constant_types(irs):
+    """
+    late conversion of uint -> type for constant (Literal)
+    :param irs:
+    :return:
+    """
+    # TODO: implement instances lookup for events, NewContract
+    was_changed = True
+    while was_changed:
+        was_changed = False
+        for ir in irs:
+            if isinstance(ir, Assignment):
+                if isinstance(ir.lvalue.type, ElementaryType):
+                    if ir.lvalue.type.type in ElementaryTypeInt:
+                        if ir.rvalue.type.type != 'int256':
+                            ir.rvalue.set_type(ElementaryType('int256'))
+                            was_changed = True
+            if isinstance(ir, Binary):
+                if isinstance(ir.lvalue.type, ElementaryType):
+                    if ir.lvalue.type.type in ElementaryTypeInt:
+                        for r in ir.read:
+                            if r.type.type != 'int256':
+                                r.set_type(ElementaryType('int256'))
+                                was_changed = True
+            if isinstance(ir, (HighLevelCall, InternalCall)):
+                func = ir.function
+                if isinstance(func, StateVariable):
+                    types = export_nested_types_from_variable(func)
+                else:
+                    types = [p.type for p in func.parameters]
+                for idx, arg in enumerate(ir.arguments):
+                    t = types[idx]
+                    if isinstance(t, ElementaryType):
+                        if t.type in ElementaryTypeInt:
+                            if arg.type.type != 'int256':
+                                arg.set_type(ElementaryType('int256'))
+                                was_changed = True
+            if isinstance(ir, NewStructure):
+                st = ir.structure
+                for idx, arg in enumerate(ir.arguments):
+                    e = st.elems_ordered[idx]
+                    if isinstance(e.type, ElementaryType):
+                        if e.type.type in ElementaryTypeInt:
+                            if arg.type.type != 'int256':
+                                arg.set_type(ElementaryType('int256'))
+                                was_changed = True
+            if isinstance(ir, InitArray):
+                if isinstance(ir.lvalue.type, ArrayType):
+                    if isinstance(ir.lvalue.type.type, ElementaryType):
+                        if ir.lvalue.type.type.type in ElementaryTypeInt:
+                            for r in ir.read:
+                                if r.type.type != 'int256':
+                                    r.set_type(ElementaryType('int256'))
+                                    was_changed = True
+
+
+
+
 # endregion
 ###################################################################################
 ###################################################################################
@ -839,6 +908,7 @@ def apply_ir_heuristics(irs, node):
    irs = propagate_type_and_convert_call(irs, node)
    irs = remove_unused(irs)
    find_references_origin(irs)
+    convert_constant_types(irs)


    return irs
--- a/slither/slithir/variables/constant.py
+++ b/slither/slithir/variables/constant.py
@ -1,17 +1,41 @@
 from .variable import SlithIRVariable
-from slither.core.solidity_types.elementary_type import ElementaryType
+from slither.core.solidity_types.elementary_type import ElementaryType, Int, Uint
+

 class Constant(SlithIRVariable):

-    def __init__(self, val):
+    def __init__(self, val, type=None):
        super(Constant, self).__init__()
        assert isinstance(val, str)
-        if val.isdigit():
-            self._type = ElementaryType('uint256')
-            self._val = int(val)
+
+        self._original_value = val
+
+        if type:
+            assert isinstance(type, ElementaryType)
+            self._type = type
+            if type.type in Int + Uint:
+                if val.startswith('0x'):
+                    self._val = int(val, 16)
+                else:
+                    if 'e' in val:
+                        base, expo = val.split('e')
+                        self._val = int(float(base)* (10 ** int(expo)))
+                    elif 'E' in val:
+                        base, expo = val.split('E')
+                        self._val = int(float(base) * (10 ** int(expo)))
+                    else:
+                        self._val = int(val)
+            elif type.type == 'bool':
+                self._val = val == 'true'
+            else:
+                self._val = val
        else:
-            self._type = ElementaryType('string')
-            self._val = val
+            if val.isdigit():
+                self._type = ElementaryType('uint256')
+                self._val = int(val)
+            else:
+                self._type = ElementaryType('string')
+                self._val = val

    @property
    def value(self):
@ -20,10 +44,18 @@ class Constant(SlithIRVariable):
        If the expression was an hexadecimal delcared as hex'...'
        return a str
        Returns:
-            (str, int)
+            (str | int | bool)
        '''
        return self._val

+    @property
+    def original_value(self):
+        '''
+        Return the string representation of the value
+        :return: str
+        '''
+        return self._original_value
+
    def __str__(self):
        return str(self.value)

--- a/slither/solc_parsing/declarations/structure.py
+++ b/slither/solc_parsing/declarations/structure.py
@ -16,6 +16,7 @@ class StructureSolc(Structure):
        self._name = name
        self._canonical_name = canonicalName
        self._elems = {}
+        self._elems_ordered = []

        self._elemsNotParsed = elems

@ -28,5 +29,6 @@ class StructureSolc(Structure):
            elem.analyze(self.contract)

            self._elems[elem.name] = elem
+            self._elems_ordered.append(elem.name)
        self._elemsNotParsed = []

--- a/slither/solc_parsing/expressions/expression_parsing.py
+++ b/slither/solc_parsing/expressions/expression_parsing.py
@ -479,6 +479,12 @@ def parse_expression(expression, caller_context):
                    value = str(convert_subdenomination(value, expression['subdenomination']))
            elif not value and value != "":
                value = '0x'+expression['hexValue']
+            type = expression['typeDescriptions']['typeString']
+
+            # Length declaration for array was None until solc 0.5.5
+            if type is None:
+                if expression['kind'] == 'number':
+                    type = 'int_const'
        else:
            value = expression['attributes']['value']
            if value:
@ -489,7 +495,15 @@ def parse_expression(expression, caller_context):
                # see https://solidity.readthedocs.io/en/v0.4.25/types.html?highlight=hex#hexadecimal-literals
                assert 'hexvalue' in expression['attributes']
                value = '0x'+expression['attributes']['hexvalue']
-        literal = Literal(value)
+            type = expression['attributes']['type']
+
+        if type.startswith('int_const '):
+            type = ElementaryType('uint256')
+        elif type.startswith('bool'):
+            type = ElementaryType('bool')
+        else:
+            type = ElementaryType('string')
+        literal = Literal(value, type)
        return literal

    elif name == 'Identifier':
--- a/slither/solc_parsing/solidity_types/type_parsing.py
+++ b/slither/solc_parsing/solidity_types/type_parsing.py
@ -32,7 +32,7 @@ def _find_from_type_name(name, contract, contracts, structures, enums):
    if name_elementary in ElementaryTypeName:
        depth = name.count('[')
        if depth:
-            return ArrayType(ElementaryType(name_elementary), Literal(depth))
+            return ArrayType(ElementaryType(name_elementary), Literal(depth, 'uint256'))
        else:
            return ElementaryType(name_elementary)
    # We first look for contract
@ -78,7 +78,7 @@ def _find_from_type_name(name, contract, contracts, structures, enums):
                depth+=1
            var_type = next((st for st in all_structures if st.contract.name+"."+st.name == name_struct), None)
            if var_type:
-                return ArrayType(UserDefinedType(var_type), Literal(depth))
+                return ArrayType(UserDefinedType(var_type), Literal(depth, 'uint256'))

    if not var_type:
        var_type = next((f for f in contract.functions if f.name == name), None)
--- a/slither/utils/type.py
+++ b/slither/utils/type.py
@ -0,0 +1,31 @@
+from slither.core.solidity_types import (ArrayType, MappingType, ElementaryType)
+
+def _add_mapping_parameter(t, l):
+    while isinstance(t, MappingType):
+        l.append(t.type_from)
+        t = t.type_to
+    _add_array_parameter(t, l)
+
+def _add_array_parameter(t, l):
+    while isinstance(t, ArrayType):
+        l.append(ElementaryType('uint256'))
+        t = t.type
+
+def export_nested_types_from_variable(variable):
+    """
+    Export the list of nested types (mapping/array)
+    :param variable:
+    :return: list(Type)
+    """
+    l = []
+    if isinstance(variable.type, MappingType):
+        t = variable.type
+        _add_mapping_parameter(t, l)
+
+    if isinstance(variable.type, ArrayType):
+        v = variable
+        _add_array_parameter(v.type, l)
+
+    return l
+
+
--- a/slither/visitors/expression/constants_folding.py
+++ b/slither/visitors/expression/constants_folding.py
@ -20,8 +20,12 @@ def set_val(expression, val):

 class ConstantFolding(ExpressionVisitor):

+    def __init__(self, expression, type):
+        super(ConstantFolding, self).__init__(expression)
+        self._type = type
+
    def result(self):
-        return Literal(int(get_val(self._expression)))
+        return Literal(int(get_val(self._expression)), self._type)

    def _post_identifier(self, expression):
        if not expression.value.is_constant:
@ -29,7 +33,7 @@ class ConstantFolding(ExpressionVisitor):
        expr = expression.value.expression
        # assumption that we won't have infinite loop
        if not isinstance(expr, Literal):
-            cf = ConstantFolding(expr)
+            cf = ConstantFolding(expr, self._type)
            expr = cf.result()
        set_val(expression, int(expr.value))

--- a/slither/visitors/slithir/expression_to_slithir.py
+++ b/slither/visitors/slithir/expression_to_slithir.py
@ -173,7 +173,8 @@ class ExpressionToSlithIR(ExpressionVisitor):
        set_val(expression, val)

    def _post_literal(self, expression):
-        set_val(expression, Constant(expression.value))
+        cst = Constant(expression.value, expression.type)
+        set_val(expression, cst)

    def _post_member_access(self, expression):
        expr = get(expression.expression)
--- a/tests/expected_json/incorrect_erc20_interface.erc20-interface.json
+++ b/tests/expected_json/incorrect_erc20_interface.erc20-interface.json
@ -3,20 +3,184 @@
    "check": "erc20-interface",
    "impact": "Medium",
    "confidence": "High",
-    "description": "Token (tests/incorrect_erc20_interface.sol#3-7) has incorrect ERC20 function interface(s):\n\t-transfer (tests/incorrect_erc20_interface.sol#5)\n",
+    "description": "Token (tests/incorrect_erc20_interface.sol#3-10) has incorrect ERC20 function interface(s):\n\t-transfer (tests/incorrect_erc20_interface.sol#4)\n\t-approve (tests/incorrect_erc20_interface.sol#5)\n\t-transferFrom (tests/incorrect_erc20_interface.sol#6)\n\t-totalSupply (tests/incorrect_erc20_interface.sol#7)\n\t-balanceOf (tests/incorrect_erc20_interface.sol#8)\n\t-allowance (tests/incorrect_erc20_interface.sol#9)\n",
    "elements": [
+      {
+        "type": "function",
+        "name": "allowance",
+        "source_mapping": {
+          "start": 319,
+          "length": 60,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+          "filename_relative": "tests/incorrect_erc20_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+          "filename_short": "tests/incorrect_erc20_interface.sol",
+          "lines": [
+            9
+          ],
+          "starting_column": 5,
+          "ending_column": 65
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 26,
+            "length": 355,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+            "filename_relative": "tests/incorrect_erc20_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+            "filename_short": "tests/incorrect_erc20_interface.sol",
+            "lines": [
+              3,
+              4,
+              5,
+              6,
+              7,
+              8,
+              9,
+              10
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
+      {
+        "type": "function",
+        "name": "approve",
+        "source_mapping": {
+          "start": 102,
+          "length": 55,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+          "filename_relative": "tests/incorrect_erc20_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+          "filename_short": "tests/incorrect_erc20_interface.sol",
+          "lines": [
+            5
+          ],
+          "starting_column": 5,
+          "ending_column": 60
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 26,
+            "length": 355,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+            "filename_relative": "tests/incorrect_erc20_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+            "filename_short": "tests/incorrect_erc20_interface.sol",
+            "lines": [
+              3,
+              4,
+              5,
+              6,
+              7,
+              8,
+              9,
+              10
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
+      {
+        "type": "function",
+        "name": "balanceOf",
+        "source_mapping": {
+          "start": 273,
+          "length": 41,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+          "filename_relative": "tests/incorrect_erc20_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+          "filename_short": "tests/incorrect_erc20_interface.sol",
+          "lines": [
+            8
+          ],
+          "starting_column": 5,
+          "ending_column": 46
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 26,
+            "length": 355,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+            "filename_relative": "tests/incorrect_erc20_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+            "filename_short": "tests/incorrect_erc20_interface.sol",
+            "lines": [
+              3,
+              4,
+              5,
+              6,
+              7,
+              8,
+              9,
+              10
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
+      {
+        "type": "function",
+        "name": "totalSupply",
+        "source_mapping": {
+          "start": 236,
+          "length": 32,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+          "filename_relative": "tests/incorrect_erc20_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+          "filename_short": "tests/incorrect_erc20_interface.sol",
+          "lines": [
+            7
+          ],
+          "starting_column": 5,
+          "ending_column": 37
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 26,
+            "length": 355,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+            "filename_relative": "tests/incorrect_erc20_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+            "filename_short": "tests/incorrect_erc20_interface.sol",
+            "lines": [
+              3,
+              4,
+              5,
+              6,
+              7,
+              8,
+              9,
+              10
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
      {
        "type": "function",
        "name": "transfer",
        "source_mapping": {
-          "start": 47,
+          "start": 46,
          "length": 51,
          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
          "filename_relative": "tests/incorrect_erc20_interface.sol",
          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
          "filename_short": "tests/incorrect_erc20_interface.sol",
          "lines": [
-            5
+            4
          ],
          "starting_column": 5,
          "ending_column": 56
@ -26,7 +190,48 @@
          "name": "Token",
          "source_mapping": {
            "start": 26,
-            "length": 75,
+            "length": 355,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+            "filename_relative": "tests/incorrect_erc20_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+            "filename_short": "tests/incorrect_erc20_interface.sol",
+            "lines": [
+              3,
+              4,
+              5,
+              6,
+              7,
+              8,
+              9,
+              10
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
+      {
+        "type": "function",
+        "name": "transferFrom",
+        "source_mapping": {
+          "start": 162,
+          "length": 69,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+          "filename_relative": "tests/incorrect_erc20_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
+          "filename_short": "tests/incorrect_erc20_interface.sol",
+          "lines": [
+            6
+          ],
+          "starting_column": 5,
+          "ending_column": 74
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 26,
+            "length": 355,
            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
            "filename_relative": "tests/incorrect_erc20_interface.sol",
            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc20_interface.sol",
@ -36,7 +241,10 @@
              4,
              5,
              6,
-              7
+              7,
+              8,
+              9,
+              10
            ],
            "starting_column": 1,
            "ending_column": 2
--- a/tests/expected_json/incorrect_erc20_interface.erc20-interface.txt
+++ b/tests/expected_json/incorrect_erc20_interface.erc20-interface.txt
@ -1,5 +1,10 @@
 INFO:Detectors:[93m
-Token (tests/incorrect_erc20_interface.sol#3-7) has incorrect ERC20 function interface(s):
-	-transfer (tests/incorrect_erc20_interface.sol#5)
+Token (tests/incorrect_erc20_interface.sol#3-10) has incorrect ERC20 function interface(s):
+	-transfer (tests/incorrect_erc20_interface.sol#4)
+	-approve (tests/incorrect_erc20_interface.sol#5)
+	-transferFrom (tests/incorrect_erc20_interface.sol#6)
+	-totalSupply (tests/incorrect_erc20_interface.sol#7)
+	-balanceOf (tests/incorrect_erc20_interface.sol#8)
+	-allowance (tests/incorrect_erc20_interface.sol#9)
 Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#incorrect-erc20-interface[0m
 INFO:Slither:tests/incorrect_erc20_interface.sol analyzed (1 contracts), 1 result(s) found
--- a/tests/expected_json/incorrect_erc721_interface.erc721-interface.json
+++ b/tests/expected_json/incorrect_erc721_interface.erc721-interface.json
@ -0,0 +1,442 @@
+[
+  {
+    "check": "erc721-interface",
+    "impact": "Medium",
+    "confidence": "High",
+    "description": "Token (tests/incorrect_erc721_interface.sol#6-16) has incorrect ERC721 function interface(s):\n\t-supportsInterface (tests/incorrect_erc721_interface.sol#4)\n\t-balanceOf (tests/incorrect_erc721_interface.sol#7)\n\t-ownerOf (tests/incorrect_erc721_interface.sol#8)\n\t-safeTransferFrom (tests/incorrect_erc721_interface.sol#9)\n\t-safeTransferFrom (tests/incorrect_erc721_interface.sol#10)\n\t-transferFrom (tests/incorrect_erc721_interface.sol#11)\n\t-approve (tests/incorrect_erc721_interface.sol#12)\n\t-setApprovalForAll (tests/incorrect_erc721_interface.sol#13)\n\t-getApproved (tests/incorrect_erc721_interface.sol#14)\n\t-isApprovedForAll (tests/incorrect_erc721_interface.sol#15)\n",
+    "elements": [
+      {
+        "type": "function",
+        "name": "approve",
+        "source_mapping": {
+          "start": 549,
+          "length": 78,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_relative": "tests/incorrect_erc721_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_short": "tests/incorrect_erc721_interface.sol",
+          "lines": [
+            12
+          ],
+          "starting_column": 5,
+          "ending_column": 83
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 109,
+            "length": 739,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_relative": "tests/incorrect_erc721_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_short": "tests/incorrect_erc721_interface.sol",
+            "lines": [
+              6,
+              7,
+              8,
+              9,
+              10,
+              11,
+              12,
+              13,
+              14,
+              15,
+              16
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
+      {
+        "type": "function",
+        "name": "balanceOf",
+        "source_mapping": {
+          "start": 140,
+          "length": 44,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_relative": "tests/incorrect_erc721_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_short": "tests/incorrect_erc721_interface.sol",
+          "lines": [
+            7
+          ],
+          "starting_column": 5,
+          "ending_column": 49
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 109,
+            "length": 739,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_relative": "tests/incorrect_erc721_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_short": "tests/incorrect_erc721_interface.sol",
+            "lines": [
+              6,
+              7,
+              8,
+              9,
+              10,
+              11,
+              12,
+              13,
+              14,
+              15,
+              16
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
+      {
+        "type": "function",
+        "name": "getApproved",
+        "source_mapping": {
+          "start": 723,
+          "length": 48,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_relative": "tests/incorrect_erc721_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_short": "tests/incorrect_erc721_interface.sol",
+          "lines": [
+            14
+          ],
+          "starting_column": 5,
+          "ending_column": 53
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 109,
+            "length": 739,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_relative": "tests/incorrect_erc721_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_short": "tests/incorrect_erc721_interface.sol",
+            "lines": [
+              6,
+              7,
+              8,
+              9,
+              10,
+              11,
+              12,
+              13,
+              14,
+              15,
+              16
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
+      {
+        "type": "function",
+        "name": "isApprovedForAll",
+        "source_mapping": {
+          "start": 776,
+          "length": 70,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_relative": "tests/incorrect_erc721_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_short": "tests/incorrect_erc721_interface.sol",
+          "lines": [
+            15
+          ],
+          "starting_column": 5,
+          "ending_column": 75
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 109,
+            "length": 739,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_relative": "tests/incorrect_erc721_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_short": "tests/incorrect_erc721_interface.sol",
+            "lines": [
+              6,
+              7,
+              8,
+              9,
+              10,
+              11,
+              12,
+              13,
+              14,
+              15,
+              16
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
+      {
+        "type": "function",
+        "name": "ownerOf",
+        "source_mapping": {
+          "start": 189,
+          "length": 44,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_relative": "tests/incorrect_erc721_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_short": "tests/incorrect_erc721_interface.sol",
+          "lines": [
+            8
+          ],
+          "starting_column": 5,
+          "ending_column": 49
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 109,
+            "length": 739,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_relative": "tests/incorrect_erc721_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_short": "tests/incorrect_erc721_interface.sol",
+            "lines": [
+              6,
+              7,
+              8,
+              9,
+              10,
+              11,
+              12,
+              13,
+              14,
+              15,
+              16
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
+      {
+        "type": "function",
+        "name": "safeTransferFrom",
+        "source_mapping": {
+          "start": 238,
+          "length": 108,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_relative": "tests/incorrect_erc721_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_short": "tests/incorrect_erc721_interface.sol",
+          "lines": [
+            9
+          ],
+          "starting_column": 5,
+          "ending_column": 113
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 109,
+            "length": 739,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_relative": "tests/incorrect_erc721_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_short": "tests/incorrect_erc721_interface.sol",
+            "lines": [
+              6,
+              7,
+              8,
+              9,
+              10,
+              11,
+              12,
+              13,
+              14,
+              15,
+              16
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
+      {
+        "type": "function",
+        "name": "safeTransferFrom",
+        "source_mapping": {
+          "start": 351,
+          "length": 96,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_relative": "tests/incorrect_erc721_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_short": "tests/incorrect_erc721_interface.sol",
+          "lines": [
+            10
+          ],
+          "starting_column": 5,
+          "ending_column": 101
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 109,
+            "length": 739,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_relative": "tests/incorrect_erc721_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_short": "tests/incorrect_erc721_interface.sol",
+            "lines": [
+              6,
+              7,
+              8,
+              9,
+              10,
+              11,
+              12,
+              13,
+              14,
+              15,
+              16
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
+      {
+        "type": "function",
+        "name": "setApprovalForAll",
+        "source_mapping": {
+          "start": 632,
+          "length": 86,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_relative": "tests/incorrect_erc721_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_short": "tests/incorrect_erc721_interface.sol",
+          "lines": [
+            13
+          ],
+          "starting_column": 5,
+          "ending_column": 91
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 109,
+            "length": 739,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_relative": "tests/incorrect_erc721_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_short": "tests/incorrect_erc721_interface.sol",
+            "lines": [
+              6,
+              7,
+              8,
+              9,
+              10,
+              11,
+              12,
+              13,
+              14,
+              15,
+              16
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
+      {
+        "type": "function",
+        "name": "supportsInterface",
+        "source_mapping": {
+          "start": 50,
+          "length": 56,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_relative": "tests/incorrect_erc721_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_short": "tests/incorrect_erc721_interface.sol",
+          "lines": [
+            4
+          ],
+          "starting_column": 5,
+          "ending_column": 61
+        },
+        "contract": {
+          "type": "contract",
+          "name": "IERC165",
+          "source_mapping": {
+            "start": 26,
+            "length": 82,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_relative": "tests/incorrect_erc721_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_short": "tests/incorrect_erc721_interface.sol",
+            "lines": [
+              3,
+              4,
+              5
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      },
+      {
+        "type": "function",
+        "name": "transferFrom",
+        "source_mapping": {
+          "start": 452,
+          "length": 92,
+          "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_relative": "tests/incorrect_erc721_interface.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+          "filename_short": "tests/incorrect_erc721_interface.sol",
+          "lines": [
+            11
+          ],
+          "starting_column": 5,
+          "ending_column": 97
+        },
+        "contract": {
+          "type": "contract",
+          "name": "Token",
+          "source_mapping": {
+            "start": 109,
+            "length": 739,
+            "filename_used": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_relative": "tests/incorrect_erc721_interface.sol",
+            "filename_absolute": "/home/travis/build/crytic/slither/tests/incorrect_erc721_interface.sol",
+            "filename_short": "tests/incorrect_erc721_interface.sol",
+            "lines": [
+              6,
+              7,
+              8,
+              9,
+              10,
+              11,
+              12,
+              13,
+              14,
+              15,
+              16
+            ],
+            "starting_column": 1,
+            "ending_column": 2
+          }
+        }
+      }
+    ]
+  }
+]
--- a/tests/expected_json/incorrect_erc721_interface.erc721-interface.txt
+++ b/tests/expected_json/incorrect_erc721_interface.erc721-interface.txt
@ -0,0 +1,14 @@
+INFO:Detectors:[93m
+Token (tests/incorrect_erc721_interface.sol#6-16) has incorrect ERC721 function interface(s):
+	-supportsInterface (tests/incorrect_erc721_interface.sol#4)
+	-balanceOf (tests/incorrect_erc721_interface.sol#7)
+	-ownerOf (tests/incorrect_erc721_interface.sol#8)
+	-safeTransferFrom (tests/incorrect_erc721_interface.sol#9)
+	-safeTransferFrom (tests/incorrect_erc721_interface.sol#10)
+	-transferFrom (tests/incorrect_erc721_interface.sol#11)
+	-approve (tests/incorrect_erc721_interface.sol#12)
+	-setApprovalForAll (tests/incorrect_erc721_interface.sol#13)
+	-getApproved (tests/incorrect_erc721_interface.sol#14)
+	-isApprovedForAll (tests/incorrect_erc721_interface.sol#15)
+Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#incorrect-erc721-interface[0m
+INFO:Slither:tests/incorrect_erc721_interface.sol analyzed (2 contracts), 1 result(s) found
--- a/tests/expected_json/too_many_digits.too-many-digits.json
+++ b/tests/expected_json/too_many_digits.too-many-digits.json
@ -0,0 +1,196 @@
+[
+  {
+    "check": "too-many-digits",
+    "impact": "Informational",
+    "confidence": "Medium",
+    "description": "C.f (tests/too_many_digits.sol#9-15) uses literals with too many digits:\n\t- x1 = 0x000001\n\t- x2 = 0x0000000000001\n\t- x3 = 1000000000000000000\n\t- x4 = 100000\n\tUse the proper denomination (ether-unit, time-unit,or the scientific notation\n",
+    "elements": [
+      {
+        "type": "expression",
+        "expression": "x1 = 0x000001",
+        "source_mapping": {
+          "start": 206,
+          "length": 18,
+          "filename_used": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_relative": "tests/too_many_digits.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_short": "tests/too_many_digits.sol",
+          "lines": [
+            10
+          ],
+          "starting_column": 9,
+          "ending_column": 27
+        }
+      },
+      {
+        "type": "expression",
+        "expression": "x2 = 0x0000000000001",
+        "source_mapping": {
+          "start": 234,
+          "length": 25,
+          "filename_used": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_relative": "tests/too_many_digits.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_short": "tests/too_many_digits.sol",
+          "lines": [
+            11
+          ],
+          "starting_column": 9,
+          "ending_column": 34
+        }
+      },
+      {
+        "type": "expression",
+        "expression": "x3 = 1000000000000000000",
+        "source_mapping": {
+          "start": 269,
+          "length": 29,
+          "filename_used": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_relative": "tests/too_many_digits.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_short": "tests/too_many_digits.sol",
+          "lines": [
+            12
+          ],
+          "starting_column": 9,
+          "ending_column": 38
+        }
+      },
+      {
+        "type": "expression",
+        "expression": "x4 = 100000",
+        "source_mapping": {
+          "start": 308,
+          "length": 16,
+          "filename_used": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_relative": "tests/too_many_digits.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_short": "tests/too_many_digits.sol",
+          "lines": [
+            13
+          ],
+          "starting_column": 9,
+          "ending_column": 25
+        }
+      }
+    ]
+  },
+  {
+    "check": "too-many-digits",
+    "impact": "Informational",
+    "confidence": "Medium",
+    "description": "C.h (tests/too_many_digits.sol#20-24) uses literals with too many digits:\n\t- x2 = 100000\n\tUse the proper denomination (ether-unit, time-unit,or the scientific notation\n",
+    "elements": [
+      {
+        "type": "expression",
+        "expression": "x2 = 100000",
+        "source_mapping": {
+          "start": 509,
+          "length": 16,
+          "filename_used": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_relative": "tests/too_many_digits.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_short": "tests/too_many_digits.sol",
+          "lines": [
+            22
+          ],
+          "starting_column": 9,
+          "ending_column": 25
+        }
+      }
+    ]
+  },
+  {
+    "check": "too-many-digits",
+    "impact": "Informational",
+    "confidence": "Medium",
+    "description": "C.i (tests/too_many_digits.sol#29-33) uses literals with too many digits:\n\t- x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000\n\t- x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000\n\t- x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000\n\t- x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000\n\t- x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000\n\tUse the proper denomination (ether-unit, time-unit,or the scientific notation\n",
+    "elements": [
+      {
+        "type": "expression",
+        "expression": "x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000",
+        "source_mapping": {
+          "start": 749,
+          "length": 67,
+          "filename_used": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_relative": "tests/too_many_digits.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_short": "tests/too_many_digits.sol",
+          "lines": [
+            31
+          ],
+          "starting_column": 9,
+          "ending_column": 76
+        }
+      },
+      {
+        "type": "expression",
+        "expression": "x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000",
+        "source_mapping": {
+          "start": 749,
+          "length": 67,
+          "filename_used": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_relative": "tests/too_many_digits.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_short": "tests/too_many_digits.sol",
+          "lines": [
+            31
+          ],
+          "starting_column": 9,
+          "ending_column": 76
+        }
+      },
+      {
+        "type": "expression",
+        "expression": "x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000",
+        "source_mapping": {
+          "start": 749,
+          "length": 67,
+          "filename_used": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_relative": "tests/too_many_digits.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_short": "tests/too_many_digits.sol",
+          "lines": [
+            31
+          ],
+          "starting_column": 9,
+          "ending_column": 76
+        }
+      },
+      {
+        "type": "expression",
+        "expression": "x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000",
+        "source_mapping": {
+          "start": 749,
+          "length": 67,
+          "filename_used": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_relative": "tests/too_many_digits.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_short": "tests/too_many_digits.sol",
+          "lines": [
+            31
+          ],
+          "starting_column": 9,
+          "ending_column": 76
+        }
+      },
+      {
+        "type": "expression",
+        "expression": "x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000",
+        "source_mapping": {
+          "start": 749,
+          "length": 67,
+          "filename_used": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_relative": "tests/too_many_digits.sol",
+          "filename_absolute": "/home/travis/build/crytic/slither/tests/too_many_digits.sol",
+          "filename_short": "tests/too_many_digits.sol",
+          "lines": [
+            31
+          ],
+          "starting_column": 9,
+          "ending_column": 76
+        }
+      }
+    ]
+  }
+]
--- a/tests/expected_json/too_many_digits.too-many-digits.txt
+++ b/tests/expected_json/too_many_digits.too-many-digits.txt
@ -0,0 +1,19 @@
+INFO:Detectors:[92m
+C.f (tests/too_many_digits.sol#9-15) uses literals with too many digits:
+	- x1 = 0x000001
+	- x2 = 0x0000000000001
+	- x3 = 1000000000000000000
+	- x4 = 100000
+	Use the proper denomination (ether-unit, time-unit,or the scientific notation
+C.h (tests/too_many_digits.sol#20-24) uses literals with too many digits:
+	- x2 = 100000
+	Use the proper denomination (ether-unit, time-unit,or the scientific notation
+C.i (tests/too_many_digits.sol#29-33) uses literals with too many digits:
+	- x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000
+	- x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000
+	- x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000
+	- x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000
+	- x2 = 1000000000000 + 10000000000000 + 100000000000000 + 1000000000000000 + 10000000000000000
+	Use the proper denomination (ether-unit, time-unit,or the scientific notation
+Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#too-many-digits[0m
+INFO:Slither:tests/too_many_digits.sol analyzed (1 contracts), 3 result(s) found
--- a/tests/incorrect_erc20_interface.sol
+++ b/tests/incorrect_erc20_interface.sol
@ -1,7 +1,10 @@
 pragma solidity ^0.4.24;

 contract Token{
-
    function transfer(address to, uint value) external;
-
+    function approve(address spender, uint value) external;
+    function transferFrom(address from, address to, uint value) external;
+    function totalSupply() external;
+    function balanceOf(address who) external;
+    function allowance(address owner, address spender) external;
 }
--- a/tests/incorrect_erc721_interface.sol
+++ b/tests/incorrect_erc721_interface.sol
@ -0,0 +1,16 @@
+pragma solidity ^0.4.24;
+
+interface IERC165 {
+    function supportsInterface(bytes4 interfaceID) external;
+}
+contract Token is IERC165{
+    function balanceOf(address _owner) external;
+    function ownerOf(uint256 _tokenId) external;
+    function safeTransferFrom(address _from, address _to, uint256 _tokenId, bytes data) external returns (bool);
+    function safeTransferFrom(address _from, address _to, uint256 _tokenId) external returns (bool);
+    function transferFrom(address _from, address _to, uint256 _tokenId) external returns (bool);
+    function approve(address _approved, uint256 _tokenId) external returns (bool);
+    function setApprovalForAll(address _operator, bool _approved) external returns (bool);
+    function getApproved(uint256 _tokenId) external;
+    function isApprovedForAll(address _owner, address _operator) external;
+}
--- a/tests/too_many_digits.sol
+++ b/tests/too_many_digits.sol
@ -0,0 +1,35 @@
+pragma solidity ^0.5.1;
+
+contract C {
+    uint balance;
+    
+    /**
+     * @dev Variables are not Ok - using too many digits in place of the Ether denomination.
+     */
+    function f() external {
+        uint x1 = 0x000001;
+        uint x2 = 0x0000000000001;
+        uint x3 = 1000000000000000000;
+        uint x4 = 100000;
+        balance += x1 + x2 + x3 + x4;
+    }
+    
+    /**
+     * @dev Variables are Ok - not using too many digits.
+     */
+    function h() external {
+        uint x1 = 1000;
+        uint x2 = 100000;
+        balance += x1 + x2 + 100;
+    }
+    
+    /**
+     * @dev Variables are Ok - Using Ether denominations.
+     */
+    function i() external {
+        uint x1 = 1 wei + 10 wei + 100 wei + 1000 wei + 10000 wei;
+        uint x2 = 1 szabo + 10 szabo + 100 szabo + 1000 szabo + 10000 szabo;
+        balance += x1 + x2;
+    }
+    
+}