path: root/libsolidity/analysis/SyntaxChecker.cpp

/*
    This file is part of solidity.

    solidity is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    solidity is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with solidity.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <libsolidity/analysis/SyntaxChecker.h>
#include <memory>
#include <libsolidity/ast/AST.h>
#include <libsolidity/ast/ExperimentalFeatures.h>
#include <libsolidity/analysis/SemVerHandler.h>
#include <libsolidity/interface/ErrorReporter.h>
#include <libsolidity/interface/Version.h>
#include <boost/algorithm/cxx11/all_of.hpp>

#include <boost/algorithm/string.hpp>
#include <string>

using namespace std;
using namespace dev;
using namespace dev::solidity;


bool SyntaxChecker::checkSyntax(ASTNode const& _astRoot)
{
    _astRoot.accept(*this);
    return Error::containsOnlyWarnings(m_errorReporter.errors());
}

bool SyntaxChecker::visit(SourceUnit const& _sourceUnit)
{
    m_versionPragmaFound = false;
    m_sourceUnit = &_sourceUnit;
    return true;
}

void SyntaxChecker::endVisit(SourceUnit const& _sourceUnit)
{
    if (!m_versionPragmaFound)
    {
        string errorString("Source file does not specify required compiler version!");
        SemVerVersion recommendedVersion{string(VersionString)};
        if (!recommendedVersion.isPrerelease())
            errorString +=
                "Consider adding \"pragma solidity ^" +
                to_string(recommendedVersion.major()) +
                string(".") +
                to_string(recommendedVersion.minor()) +
                string(".") +
                to_string(recommendedVersion.patch()) +
                string(";\"");

        m_errorReporter.warning(_sourceUnit.location(), errorString);
    }
    m_sourceUnit = nullptr;
}

bool SyntaxChecker::visit(PragmaDirective const& _pragma)
{
    solAssert(!_pragma.tokens().empty(), "");
    solAssert(_pragma.tokens().size() == _pragma.literals().size(), "");
    if (_pragma.tokens()[0] != Token::Identifier)
        m_errorReporter.syntaxError(_pragma.location(), "Invalid pragma \"" + _pragma.literals()[0] + "\"");
    else if (_pragma.literals()[0] == "experimental")
    {
        solAssert(m_sourceUnit, "");
        vector<string> literals(_pragma.literals().begin() + 1, _pragma.literals().end());
        if (literals.empty())
            m_errorReporter.syntaxError(
                _pragma.location(),
                "Experimental feature name is missing."
            );
        else if (literals.size() > 1)
            m_errorReporter.syntaxError(
                _pragma.location(),
                "Stray arguments."
            );
        else
        {
            string const literal = literals[0];
            if (literal.empty())
                m_errorReporter.syntaxError(_pragma.location(), "Empty experimental feature name is invalid.");
            else if (!ExperimentalFeatureNames.count(literal))
                m_errorReporter.syntaxError(_pragma.location(), "Unsupported experimental feature name.");
            else if (m_sourceUnit->annotation().experimentalFeatures.count(ExperimentalFeatureNames.at(literal)))
                m_errorReporter.syntaxError(_pragma.location(), "Duplicate experimental feature name.");
            else
            {
                auto feature = ExperimentalFeatureNames.at(literal);
                m_sourceUnit->annotation().experimentalFeatures.insert(feature);
                if (!ExperimentalFeatureOnlyAnalysis.count(feature))
                    m_errorReporter.warning(_pragma.location(), "Experimental features are turned on. Do not use experimental features on live deployments.");
            }
        }
    }
    else if (_pragma.literals()[0] == "solidity")
    {
        vector<Token::Value> tokens(_pragma.tokens().begin() + 1, _pragma.tokens().end());
        vector<string> literals(_pragma.literals().begin() + 1, _pragma.literals().end());
        SemVerMatchExpressionParser parser(tokens, literals);
        auto matchExpression = parser.parse();
        SemVerVersion currentVersion{string(VersionString)};
        if (!matchExpression.matches(currentVersion))
            m_errorReporter.syntaxError(
                _pragma.location(),
                "Source file requires different compiler version (current compiler is " +
                string(VersionString) + " - note that nightly builds are considered to be "
                "strictly less than the released version"
            );
        m_versionPragmaFound = true;
    }
    else
        m_errorReporter.syntaxError(_pragma.location(), "Unknown pragma \"" + _pragma.literals()[0] + "\"");
    return true;
}

bool SyntaxChecker::visit(ModifierDefinition const&)
{
    m_placeholderFound = false;
    return true;
}

void SyntaxChecker::endVisit(ModifierDefinition const& _modifier)
{
    if (!m_placeholderFound)
        m_errorReporter.syntaxError(_modifier.body().location(), "Modifier body does not contain '_'.");
    m_placeholderFound = false;
}

void SyntaxChecker::checkSingleStatementVariableDeclaration(ASTNode const& _statement)
{
    auto varDecl = dynamic_cast<VariableDeclarationStatement const*>(&_statement);
    if (varDecl)
        m_errorReporter.syntaxError(_statement.location(), "Variable declarations can only be used inside blocks.");
}

bool SyntaxChecker::visit(IfStatement const& _ifStatement)
{
    checkSingleStatementVariableDeclaration(_ifStatement.trueStatement());
    if (Statement const* _statement = _ifStatement.falseStatement())
        checkSingleStatementVariableDeclaration(*_statement);
    return true;
}

bool SyntaxChecker::visit(WhileStatement const& _whileStatement)
{
    m_inLoopDepth++;
    checkSingleStatementVariableDeclaration(_whileStatement.body());
    return true;
}

void SyntaxChecker::endVisit(WhileStatement const&)
{
    m_inLoopDepth--;
}

bool SyntaxChecker::visit(ForStatement const& _forStatement)
{
    m_inLoopDepth++;
    checkSingleStatementVariableDeclaration(_forStatement.body());
    return true;
}

void SyntaxChecker::endVisit(ForStatement const&)
{
    m_inLoopDepth--;
}

bool SyntaxChecker::visit(Continue const& _continueStatement)
{
    if (m_inLoopDepth <= 0)
        // we're not in a for/while loop, report syntax error
        m_errorReporter.syntaxError(_continueStatement.location(), "\"continue\" has to be in a \"for\" or \"while\" loop.");
    return true;
}

bool SyntaxChecker::visit(Break const& _breakStatement)
{
    if (m_inLoopDepth <= 0)
        // we're not in a for/while loop, report syntax error
        m_errorReporter.syntaxError(_breakStatement.location(), "\"break\" has to be in a \"for\" or \"while\" loop.");
    return true;
}

bool SyntaxChecker::visit(Throw const& _throwStatement)
{
    m_errorReporter.syntaxError(
        _throwStatement.location(),
        "\"throw\" is deprecated in favour of \"revert()\", \"require()\" and \"assert()\"."
    );

    return true;
}

bool SyntaxChecker::visit(Literal const& _literal)
{
    if (_literal.token() != Token::Number)
        return true;

    ASTString const& value = _literal.value();
    solAssert(!value.empty(), "");

    // Generic checks no matter what base this number literal is of:
    if (value.back() == '_')
    {
        m_errorReporter.syntaxError(_literal.location(), "Invalid use of underscores in number literal. No trailing underscores allowed.");
        return true;
    }

    if (value.find("__") != ASTString::npos)
    {
        m_errorReporter.syntaxError(_literal.location(), "Invalid use of underscores in number literal. Only one consecutive underscores between digits allowed.");
        return true;
    }

    if (!_literal.isHexNumber()) // decimal literal
    {
        if (value.find("._") != ASTString::npos)
            m_errorReporter.syntaxError(_literal.location(), "Invalid use of underscores in number literal. No underscores in front of the fraction part allowed.");

        if (value.find("_.") != ASTString::npos)
            m_errorReporter.syntaxError(_literal.location(), "Invalid use of underscores in number literal. No underscores in front of the fraction part allowed.");

        if (value.find("_e") != ASTString::npos)
            m_errorReporter.syntaxError(_literal.location(), "Invalid use of underscores in number literal. No underscore at the end of the mantissa allowed.");

        if (value.find("e_") != ASTString::npos)
            m_errorReporter.syntaxError(_literal.location(), "Invalid use of underscores in number literal. No underscore in front of exponent allowed.");
    }

    return true;
}

bool SyntaxChecker::visit(UnaryOperation const& _operation)
{
    if (_operation.getOperator() == Token::Add)
        m_errorReporter.syntaxError(_operation.location(), "Use of unary + is disallowed.");

    return true;
}

bool SyntaxChecker::visit(PlaceholderStatement const&)
{
    m_placeholderFound = true;
    return true;
}

bool SyntaxChecker::visit(ContractDefinition const& _contract)
{
    m_isInterface = _contract.contractKind() == ContractDefinition::ContractKind::Interface;

    ASTString const& contractName = _contract.name();
    for (FunctionDefinition const* function: _contract.definedFunctions())
        if (function->name() == contractName)
            m_errorReporter.syntaxError(function->location(),
                "Functions are not allowed to have the same name as the contract. "
                "If you intend this to be a constructor, use \"constructor(...) { ... }\" to define it."
            );
    return true;
}

bool SyntaxChecker::visit(FunctionDefinition const& _function)
{
    if (_function.noVisibilitySpecified())
    {
        string suggestedVisibility = _function.isFallback() || m_isInterface ? "external" : "public";
        m_errorReporter.syntaxError(
            _function.location(),
            "No visibility specified. Did you intend to add \"" + suggestedVisibility + "\"?"
        );
    }

    if (!_function.isImplemented() && !_function.modifiers().empty())
        m_errorReporter.syntaxError(_function.location(), "Functions without implementation cannot have modifiers.");

    return true;
}

bool SyntaxChecker::visit(FunctionTypeName const& _node)
{
    for (auto const& decl: _node.parameterTypeList()->parameters())
        if (!decl->name().empty())
            m_errorReporter.warning(decl->location(), "Naming function type parameters is deprecated.");

    for (auto const& decl: _node.returnParameterTypeList()->parameters())
        if (!decl->name().empty())
            m_errorReporter.syntaxError(decl->location(), "Return parameters in function types may not be named.");

    return true;
}

bool SyntaxChecker::visit(VariableDeclarationStatement const& _statement)
{
    // Report if none of the variable components in the tuple have a name (only possible via deprecated "var")
    if (boost::algorithm::all_of_equal(_statement.declarations(), nullptr))
        m_errorReporter.syntaxError(
            _statement.location(),
            "The use of the \"var\" keyword is disallowed. The declaration part of the statement can be removed, since it is empty."
        );

    return true;
}

bool SyntaxChecker::visit(StructDefinition const& _struct)
{
    if (_struct.members().empty())
        m_errorReporter.syntaxError(_struct.location(), "Defining empty structs is disallowed.");

    return true;
}