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Warn on unused local variables

Browse Source 
Analyze functions for all local variables, parameters, and named
return variables which are never used in the function, and issue
a warning.
This commit is contained in:
Rhett Aultman 2017-04-14 07:48:59 -07:00 committed by chriseth
parent c09f071ff6
commit a40c8cfb68
5 changed files with 205 additions and 36 deletions
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1
Changelog.md
View File

@ -10,6 +10,7 @@ Features:
* Inline Assembly: Storage variable access using ``_slot`` and ``_offset`` suffixes.
* Inline Assembly: Disallow blocks with unbalanced stack.
* Static analyzer: Warn about statements without effects.
* Static analyzer: Warn about unused local variables, parameters, and return parameters.
* Syntax checker: issue deprecation warning for unary '+'
Bugfixes:

39
libsolidity/analysis/StaticAnalyzer.cpp
View File

@ -48,13 +48,52 @@ void StaticAnalyzer::endVisit(ContractDefinition const&)
bool StaticAnalyzer::visit(FunctionDefinition const& _function)
{
if (_function.isImplemented())
m_inFunction = true;
m_localVarUseCount.clear();
m_nonPayablePublic = _function.isPublic() && !_function.isPayable();
return true;
}
void StaticAnalyzer::endVisit(FunctionDefinition const&)
{
m_inFunction = false;
m_nonPayablePublic = false;
for (auto const& var: m_localVarUseCount)
if (var.second == 0)
warning(var.first->location(), "Unused local variable");
}
bool StaticAnalyzer::visit(Identifier const& _identifier)
{
if (m_inFunction)
{
if (auto var = dynamic_cast<VariableDeclaration const*>(_identifier.annotation().referencedDeclaration))
{
solAssert(!var->name().empty(), "");
if (var->isLocalVariable())
m_localVarUseCount[var] += 1;
}
}
return true;
}
bool StaticAnalyzer::visit(VariableDeclaration const& _variable)
{
if (m_inFunction)
{
solAssert(_variable.isLocalVariable(), "");
if (_variable.name() != "")
{
// The variable may have been used before reaching the
// declaration. If it was, we must not reset the counter,
// but since [] will insert the default 0, we really just
// need to access the map here and let it do the rest on its
// own.
m_localVarUseCount[&_variable];
}
}
return true;
}
bool StaticAnalyzer::visit(ExpressionStatement const& _statement)

6
libsolidity/analysis/StaticAnalyzer.h
View File

@ -61,6 +61,8 @@ private:
virtual void endVisit(FunctionDefinition const& _function) override;
virtual bool visit(ExpressionStatement const& _statement) override;
virtual bool visit(VariableDeclaration const& _variable) override;
virtual bool visit(Identifier const& _identifier) override;
virtual bool visit(MemberAccess const& _memberAccess) override;
@ -71,6 +73,10 @@ private:
/// Flag that indicates whether a public function does not contain the "payable" modifier.
bool m_nonPayablePublic = false;
std::map<VariableDeclaration const*, int> m_localVarUseCount;
bool m_inFunction = false;
};
}

10
std/StandardToken.sol
View File

@ -22,10 +22,10 @@ contract StandardToken is Token {
}
function transfer(address _to, uint256 _value) returns (bool success) {
return doTransfer(msg.sender, _to, _value);
success = doTransfer(msg.sender, _to, _value);
}
function transferFrom(address _from, address _to, uint256 _value) returns (bool success) {
function transferFrom(address _from, address _to, uint256 _value) returns (bool) {
if (m_allowance[_from][msg.sender] >= _value) {
if (doTransfer(_from, _to, _value)) {
m_allowance[_from][msg.sender] -= _value;
@ -36,7 +36,7 @@ contract StandardToken is Token {
}
}
function doTransfer(address _from, address _to, uint _value) internal returns (bool success) {
function doTransfer(address _from, address _to, uint _value) internal returns (bool) {
if (balance[_from] >= _value && balance[_to] + _value >= balance[_to]) {
balance[_from] -= _value;
balance[_to] += _value;
@ -47,13 +47,13 @@ contract StandardToken is Token {
}
}
function approve(address _spender, uint256 _value) returns (bool success) {
function approve(address _spender, uint256 _value) returns (bool) {
m_allowance[msg.sender][_spender] = _value;
Approval(msg.sender, _spender, _value);
return true;
}
function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
function allowance(address _owner, address _spender) constant returns (uint256) {
return m_allowance[_owner][_spender];
}
}

185
test/libsolidity/SolidityNameAndTypeResolution.cpp
View File

@ -216,7 +216,7 @@ BOOST_AUTO_TEST_CASE(smoke_test)
char const* text = R"(
contract test {
uint256 stateVariable1;
function fun(uint256 arg1) { uint256 y; }
function fun(uint256 arg1) { uint256 y; y = arg1; }
}
)";
CHECK_SUCCESS(text);
@ -237,8 +237,8 @@ BOOST_AUTO_TEST_CASE(double_function_declaration)
{
char const* text = R"(
contract test {
function fun() { uint x; }
function fun() { uint x; }
function fun() { }
function fun() { }
}
)";
CHECK_ERROR(text, DeclarationError, "");
@ -262,7 +262,7 @@ BOOST_AUTO_TEST_CASE(name_shadowing)
char const* text = R"(
contract test {
uint256 variable;
function f() { uint32 variable; }
function f() { uint32 variable; variable; }
}
)";
CHECK_SUCCESS(text);
@ -273,7 +273,7 @@ BOOST_AUTO_TEST_CASE(name_references)
char const* text = R"(
contract test {
uint256 variable;
function f(uint256 arg) returns (uint out) { f(variable); test; out; }
function f(uint256) returns (uint out) { f(variable); test; out; }
}
)";
CHECK_SUCCESS(text);
@ -404,8 +404,8 @@ BOOST_AUTO_TEST_CASE(type_checking_function_call)
{
char const* text = R"(
contract test {
function f() returns (bool r) { return g(12, true) == 3; }
function g(uint256 a, bool b) returns (uint256 r) { }
function f() returns (bool) { return g(12, true) == 3; }
function g(uint256, bool) returns (uint256) { }
}
)";
CHECK_SUCCESS(text);
@ -523,12 +523,12 @@ BOOST_AUTO_TEST_CASE(forward_function_reference)
{
char const* text = R"(
contract First {
function fun() returns (bool ret) {
function fun() returns (bool) {
return Second(1).fun(1, true, 3) > 0;
}
}
contract Second {
function fun(uint a, bool b, uint c) returns (uint ret) {
function fun(uint, bool, uint) returns (uint) {
if (First(2).fun() == true) return 1;
}
}
@ -636,10 +636,10 @@ BOOST_AUTO_TEST_CASE(abstract_contract_constructor_args_not_provided)
{
ASTPointer<SourceUnit> sourceUnit;
char const* text = R"(
contract BaseBase { function BaseBase(uint j); }
contract BaseBase { function BaseBase(uint); }
contract base is BaseBase { function foo(); }
contract derived is base {
function derived(uint i) {}
function derived(uint) {}
function foo() {}
}
)";
@ -701,7 +701,7 @@ BOOST_AUTO_TEST_CASE(function_canonical_signature_type_aliases)
ASTPointer<SourceUnit> sourceUnit;
char const* text = R"(
contract Test {
function boo(uint arg1, bytes32 arg2, address arg3) returns (uint ret) {
function boo(uint, bytes32, address) returns (uint ret) {
ret = 5;
}
}
@ -725,7 +725,7 @@ BOOST_AUTO_TEST_CASE(function_external_types)
uint a;
}
contract Test {
function boo(uint arg2, bool arg3, bytes8 arg4, bool[2] pairs, uint[] dynamic, C carg, address[] addresses) external returns (uint ret) {
function boo(uint, bool, bytes8, bool[2], uint[], C, address[]) external returns (uint ret) {
ret = 5;
}
}
@ -914,7 +914,7 @@ BOOST_AUTO_TEST_CASE(complex_inheritance)
{
char const* text = R"(
contract A { function f() { uint8 x = C(0).g(); } }
contract B { function f() {} function g() returns (uint8 r) {} }
contract B { function f() {} function g() returns (uint8) {} }
contract C is A, B { }
)";
CHECK_SUCCESS(text);
@ -1672,7 +1672,7 @@ BOOST_AUTO_TEST_CASE(exp_warn_literal_base)
{
char const* sourceCode = R"(
contract test {
function f() returns(uint d) {
function f() returns(uint) {
uint8 x = 100;
return 10**x;
}
@ -1681,7 +1681,7 @@ BOOST_AUTO_TEST_CASE(exp_warn_literal_base)
CHECK_WARNING(sourceCode, "might overflow");
sourceCode = R"(
contract test {
function f() returns(uint d) {
function f() returns(uint) {
uint8 x = 100;
return uint8(10)**x;
}
@ -1690,7 +1690,7 @@ BOOST_AUTO_TEST_CASE(exp_warn_literal_base)
CHECK_SUCCESS(sourceCode);
sourceCode = R"(
contract test {
function f() returns(uint d) {
function f() returns(uint) {
return 2**80;
}
}
@ -1941,10 +1941,10 @@ BOOST_AUTO_TEST_CASE(test_for_bug_override_function_with_bytearray_type)
{
char const* sourceCode = R"(
contract Vehicle {
function f(bytes _a) external returns (uint256 r) {r = 1;}
function f(bytes) external returns (uint256 r) {r = 1;}
}
contract Bike is Vehicle {
function f(bytes _a) external returns (uint256 r) {r = 42;}
function f(bytes) external returns (uint256 r) {r = 42;}
}
)";
ETH_TEST_CHECK_NO_THROW(parseAndAnalyse(sourceCode), "Parsing and Name Resolving failed");
@ -2570,6 +2570,7 @@ BOOST_AUTO_TEST_CASE(storage_location_local_variables)
uint[] storage x;
uint[] memory y;
uint[] memory z;
x;y;z;
}
}
)";
@ -2625,6 +2626,7 @@ BOOST_AUTO_TEST_CASE(uninitialized_mapping_variable)
contract C {
function f() {
mapping(uint => uint) x;
x;
}
}
)";
@ -2637,6 +2639,7 @@ BOOST_AUTO_TEST_CASE(uninitialized_mapping_array_variable)
contract C {
function f() {
mapping(uint => uint)[] x;
x;
}
}
)";
@ -2789,6 +2792,7 @@ BOOST_AUTO_TEST_CASE(literal_strings)
function f() {
string memory long = "01234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890";
string memory short = "123";
long; short;
}
}
)";
@ -2865,7 +2869,7 @@ BOOST_AUTO_TEST_CASE(call_to_library_function)
{
char const* text = R"(
library Lib {
function min(uint x, uint y) returns (uint);
function min(uint, uint) returns (uint);
}
contract Test {
function f() {
@ -2963,9 +2967,9 @@ BOOST_AUTO_TEST_CASE(cyclic_binary_dependency_via_inheritance)
BOOST_AUTO_TEST_CASE(multi_variable_declaration_fail)
{
char const* text = R"(
contract C { function f() { var (x,y); } }
contract C { function f() { var (x,y); x = 1; y = 1;} }
)";
CHECK_ERROR(text, TypeError, "");
CHECK_ERROR(text, TypeError, "Assignment necessary for type detection.");
}
BOOST_AUTO_TEST_CASE(multi_variable_declaration_wildcards_fine)
@ -2982,6 +2986,7 @@ BOOST_AUTO_TEST_CASE(multi_variable_declaration_wildcards_fine)
var (,e,g) = two();
var (,,) = three();
var () = none();
a;b;c;d;e;g;
}
}
)";
@ -3040,6 +3045,7 @@ BOOST_AUTO_TEST_CASE(tuples)
var (b,) = (1,);
var (c,d) = (1, 2 + a);
var (e,) = (1, 2, b);
a;b;c;d;e;
}
}
)";
@ -3197,7 +3203,7 @@ BOOST_AUTO_TEST_CASE(using_for_overload)
library D {
struct s { uint a; }
function mul(s storage self, uint x) returns (uint) { return self.a *= x; }
function mul(s storage self, bytes32 x) returns (bytes32) { }
function mul(s storage, bytes32) returns (bytes32) { }
}
contract C {
using D for D.s;
@ -3309,6 +3315,7 @@ BOOST_AUTO_TEST_CASE(create_memory_arrays)
L.S[][] memory x = new L.S[][](10);
var y = new uint[](20);
var z = new bytes(size);
x;y;z;
}
}
)";
@ -3355,8 +3362,8 @@ BOOST_AUTO_TEST_CASE(function_overload_array_type)
{
char const* text = R"(
contract M {
function f(uint[] values);
function f(int[] values);
function f(uint[]);
function f(int[]);
}
)";
CHECK_SUCCESS(text);
@ -3654,16 +3661,20 @@ BOOST_AUTO_TEST_CASE(conditional_with_all_types)
uint x;
uint y;
uint g = true ? x : y;
g += 1; // Avoid unused var warning
// integer constants
uint h = true ? 1 : 3;
h += 1; // Avoid unused var warning
// string literal
var i = true ? "hello" : "world";
i = "used"; //Avoid unused var warning
}
function f2() {
// bool
bool j = true ? true : false;
j = j && true; // Avoid unused var warning
// real is not there yet.
@ -3671,15 +3682,19 @@ BOOST_AUTO_TEST_CASE(conditional_with_all_types)
byte[2] memory a;
byte[2] memory b;
var k = true ? a : b;
k[0] = 0; //Avoid unused var warning
bytes memory e;
bytes memory f;
var l = true ? e : f;
l[0] = 0; // Avoid unused var warning
// fixed bytes
bytes2 c;
bytes2 d;
var m = true ? c : d;
m &= m;
}
function f3() {
// contract doesn't fit in here
@ -3689,7 +3704,7 @@ BOOST_AUTO_TEST_CASE(conditional_with_all_types)
// function
var r = true ? fun_x : fun_y;
r(); // Avoid unused var warning
// enum
small enum_x;
small enum_y;
@ -3697,13 +3712,13 @@ BOOST_AUTO_TEST_CASE(conditional_with_all_types)
// tuple
var (n, o) = true ? (1, 2) : (3, 4);
(n, o) = (o, n); // Avoid unused var warning
// mapping
var p = true ? table1 : table2;
p[0] = 0; // Avoid unused var warning
// typetype
var q = true ? uint32(1) : uint32(2);
q += 1; // Avoid unused var warning
// modifier doesn't fit in here
// magic doesn't fit in here
@ -3753,6 +3768,7 @@ BOOST_AUTO_TEST_CASE(uint7_and_uintM_as_identifier)
uint7 = 5;
string memory intM;
uint bytesM = 21;
intM; bytesM;
}
}
)";
@ -3804,6 +3820,7 @@ BOOST_AUTO_TEST_CASE(int10abc_is_identifier)
function f() {
uint uint10abc = 3;
int int10abc = 4;
uint10abc; int10abc;
}
}
)";
@ -3888,6 +3905,7 @@ BOOST_AUTO_TEST_CASE(fixed_type_int_conversion)
int128 b = 4;
fixed c = b;
ufixed d = a;
c; d;
}
}
)";
@ -3901,6 +3919,7 @@ BOOST_AUTO_TEST_CASE(fixed_type_rational_int_conversion)
function f() {
fixed c = 3;
ufixed d = 4;
c; d;
}
}
)";
@ -3914,6 +3933,7 @@ BOOST_AUTO_TEST_CASE(fixed_type_rational_fraction_conversion)
function f() {
fixed a = 4.5;
ufixed d = 2.5;
a; d;
}
}
)";
@ -3927,6 +3947,7 @@ BOOST_AUTO_TEST_CASE(invalid_int_implicit_conversion_from_fixed)
function f() {
fixed a = 4.5;
int b = a;
a; b;
}
}
)";
@ -3949,6 +3970,7 @@ BOOST_AUTO_TEST_CASE(rational_unary_operation)
function f() {
ufixed8x16 a = +3.25;
fixed8x16 b = -3.25;
a; b;
}
}
)";
@ -3972,6 +3994,7 @@ BOOST_AUTO_TEST_CASE(leading_zero_rationals_convert)
ufixed0x56 b = 0.0000000000000006661338147750939242541790008544921875;
fixed0x8 c = -0.5;
fixed0x56 d = -0.0000000000000006661338147750939242541790008544921875;
a; b; c; d;
}
}
)";
@ -3989,6 +4012,7 @@ BOOST_AUTO_TEST_CASE(size_capabilities_of_fixed_point_types)
fixed248x8 d = -123456781234567979695948382928485849359686494864095409282048094275023098123.5;
fixed0x256 e = -0.93322335481643744342575580035176794825198893968114429702091846411734101080123092162893656820177312738451291806995868682861328125;
fixed0x256 g = -0.00011788606643744342575580035176794825198893968114429702091846411734101080123092162893656820177312738451291806995868682861328125;
a; b; c; d; e; g;
}
}
)";
@ -4028,6 +4052,7 @@ BOOST_AUTO_TEST_CASE(fixed_type_valid_explicit_conversions)
ufixed0x256 a = ufixed0x256(1/3);
ufixed0x248 b = ufixed0x248(1/3);
ufixed0x8 c = ufixed0x8(1/3);
a; b; c;
}
}
)";
@ -4159,6 +4184,7 @@ BOOST_AUTO_TEST_CASE(rational_to_fixed_literal_expression)
ufixed8x248 e = ufixed8x248(35.245 % 12.9);
ufixed8x248 f = ufixed8x248(1.2 % 2);
fixed g = 2 ** -2;
a; b; c; d; e; f; g;
}
}
)";
@ -4269,6 +4295,7 @@ BOOST_AUTO_TEST_CASE(var_capable_of_holding_constant_rationals)
var a = 0.12345678;
var b = 12345678.352;
var c = 0.00000009;
a; b; c;
}
}
)";
@ -4281,6 +4308,7 @@ BOOST_AUTO_TEST_CASE(var_and_rational_with_tuple)
contract test {
function f() {
var (a, b) = (.5, 1/3);
a; b;
}
}
)";
@ -4354,6 +4382,7 @@ BOOST_AUTO_TEST_CASE(zero_handling)
function f() {
fixed8x8 a = 0;
ufixed8x8 b = 0;
a; b;
}
}
)";
@ -4859,6 +4888,7 @@ BOOST_AUTO_TEST_CASE(function_type_arrays)
function(uint) returns (uint)[10] storage b = y;
function(uint) external returns (uint)[] memory c;
c = new function(uint) external returns (uint)[](200);
a; b;
}
}
)";
@ -4917,8 +4947,8 @@ BOOST_AUTO_TEST_CASE(external_function_to_function_type_calldata_parameter)
// when converting to a function type.
char const* text = R"(
contract C {
function f(function(bytes memory x) external g) { }
function callback(bytes x) external {}
function f(function(bytes memory) external g) { }
function callback(bytes) external {}
function g() {
f(this.callback);
}
@ -5287,6 +5317,7 @@ BOOST_AUTO_TEST_CASE(invalid_address_checksum)
contract C {
function f() {
var x = 0xFA0bFc97E48458494Ccd857e1A85DC91F7F0046E;
x;
}
}
)";
@ -5299,6 +5330,7 @@ BOOST_AUTO_TEST_CASE(invalid_address_no_checksum)
contract C {
function f() {
var x = 0xfa0bfc97e48458494ccd857e1a85dc91f7f0046e;
x;
}
}
)";
@ -5311,6 +5343,7 @@ BOOST_AUTO_TEST_CASE(invalid_address_length)
contract C {
function f() {
var x = 0xA0bFc97E48458494Ccd857e1A85DC91F7F0046E;
x;
}
}
)";
@ -5345,6 +5378,7 @@ BOOST_AUTO_TEST_CASE(address_methods)
bool delegatecallRet = addr.delegatecall();
bool sendRet = addr.send(1);
addr.transfer(1);
callRet; callcodeRet; delegatecallRet; sendRet;
}
}
)";
@ -5571,6 +5605,95 @@ BOOST_AUTO_TEST_CASE(pure_statement_check_for_regular_for_loop)
success(text);
}
BOOST_AUTO_TEST_CASE(warn_unused_local)
{
char const* text = R"(
contract C {
function f() {
uint a;
}
}
)";
CHECK_WARNING(text, "Unused");
}
BOOST_AUTO_TEST_CASE(warn_unused_local_assigned)
{
char const* text = R"(
contract C {
function f() {
var a = 1;
}
}
)";
CHECK_WARNING(text, "Unused");
}
BOOST_AUTO_TEST_CASE(warn_unused_param)
{
char const* text = R"(
contract C {
function f(uint a) {
}
}
)";
CHECK_WARNING(text, "Unused");
text = R"(
contract C {
function f(uint) {
}
}
)";
success(text);
}
BOOST_AUTO_TEST_CASE(warn_unused_return_param)
{
char const* text = R"(
contract C {
function f() returns (uint a) {
}
}
)";
CHECK_WARNING(text, "Unused");
text = R"(
contract C {
function f() returns (uint) {
}
}
)";
success(text);
}
BOOST_AUTO_TEST_CASE(no_unused_warnings)
{
char const* text = R"(
contract C {
function f(uint a) returns (uint b) {
uint c = 1;
b = a + c;
}
}
)";
success(text);
}
BOOST_AUTO_TEST_CASE(no_unused_dec_after_use)
{
char const* text = R"(
contract C {
function f() {
a = 7;
uint a;
}
}
)";
success(text);
}
BOOST_AUTO_TEST_SUITE_END()
}