implement overload resolution

8 files changed, 210 insertions, 39 deletions

diff --git a/AST.cpp b/AST.cpp
index 79b755e9..428c82f2 100644
--- a/AST.cpp
+++ b/AST.cpp
@@ -76,6 +76,15 @@ void ContractDefinition::checkTypeRequirements()
 
 	for (ASTPointer<FunctionDefinition> const& function: getDefinedFunctions())
 		function->checkTypeRequirements();
+	// check for duplicate declaration
+	set<string> functions;
+	for (ASTPointer<FunctionDefinition> const& function: getDefinedFunctions())
+	{
+		string signature = function->getCanonicalSignature();
+		if (functions.count(signature))
+			BOOST_THROW_EXCEPTION(DeclarationError() << errinfo_comment("Duplicate functions are not allowed."));
+		functions.insert(signature);
+	}
 
 	for (ASTPointer<VariableDeclaration> const& variable: m_stateVariables)
 		variable->checkTypeRequirements();
@@ -129,6 +138,7 @@ void ContractDefinition::checkIllegalOverrides() const
 	// TODO unify this at a later point. for this we need to put the constness and the access specifier
 	// into the types
 	map<string, FunctionDefinition const*> functions;
+	set<string> functionNames;
 	map<string, ModifierDefinition const*> modifiers;
 
 	// We search from derived to base, so the stored item causes the error.
@@ -141,7 +151,8 @@ void ContractDefinition::checkIllegalOverrides() const
 			string const& name = function->getName();
 			if (modifiers.count(name))
 				BOOST_THROW_EXCEPTION(modifiers[name]->createTypeError("Override changes function to modifier."));
-			FunctionDefinition const*& override = functions[name];
+			FunctionDefinition const*& override = functions[function->getCanonicalSignature()];
+			functionNames.insert(name);
 			if (!override)
 				override = function.get();
 			else if (override->getVisibility() != function->getVisibility() ||
@@ -152,13 +163,13 @@ void ContractDefinition::checkIllegalOverrides() const
 		for (ASTPointer<ModifierDefinition> const& modifier: contract->getFunctionModifiers())
 		{
 			string const& name = modifier->getName();
-			if (functions.count(name))
-				BOOST_THROW_EXCEPTION(functions[name]->createTypeError("Override changes modifier to function."));
 			ModifierDefinition const*& override = modifiers[name];
 			if (!override)
 				override = modifier.get();
 			else if (ModifierType(*override) != ModifierType(*modifier))
 				BOOST_THROW_EXCEPTION(override->createTypeError("Override changes modifier signature."));
+			if (functionNames.count(name))
+				BOOST_THROW_EXCEPTION(override->createTypeError("Override changes modifier to function."));
 		}
 	}
 }
@@ -185,16 +196,21 @@ vector<pair<FixedHash<4>, FunctionTypePointer>> const& ContractDefinition::getIn
 	if (!m_interfaceFunctionList)
 	{
 		set<string> functionsSeen;
+		set<string> signaturesSeen;
 		m_interfaceFunctionList.reset(new vector<pair<FixedHash<4>, FunctionTypePointer>>());
 		for (ContractDefinition const* contract: getLinearizedBaseContracts())
 		{
 			for (ASTPointer<FunctionDefinition> const& f: contract->getDefinedFunctions())
-				if (f->isPublic() && !f->isConstructor() && !f->getName().empty() && functionsSeen.count(f->getName()) == 0)
+			{
+				string functionSignature = f->getCanonicalSignature();
+				if (f->isPublic() && !f->isConstructor() && !f->getName().empty() && signaturesSeen.count(functionSignature) == 0)
 				{
 					functionsSeen.insert(f->getName());
-					FixedHash<4> hash(dev::sha3(f->getCanonicalSignature()));
+					signaturesSeen.insert(functionSignature);
+					FixedHash<4> hash(dev::sha3(functionSignature));
 					m_interfaceFunctionList->push_back(make_pair(hash, make_shared<FunctionType>(*f, false)));
 				}
+			}
 
 			for (ASTPointer<VariableDeclaration> const& v: contract->getStateVariables())
 				if (v->isPublic() && functionsSeen.count(v->getName()) == 0)
@@ -467,7 +483,43 @@ void Return::checkTypeRequirements()
 
 void VariableDeclarationStatement::checkTypeRequirements()
 {
+<<<<<<< HEAD
 	m_variable->checkTypeRequirements();
+=======
+	// Variables can be declared without type (with "var"), in which case the first assignment
+	// sets the type.
+	// Note that assignments before the first declaration are legal because of the special scoping
+	// rules inherited from JavaScript.
+	if (m_variable->getValue())
+	{
+		if (m_variable->getType())
+		{
+			std::cout << "getType() ok" << std::endl;
+			m_variable->getValue()->expectType(*m_variable->getType());
+		}
+		else
+		{
+			// no type declared and no previous assignment, infer the type
+			std::cout << "here's where called...." << std::endl;
+			Identifier* identifier = dynamic_cast<Identifier*>(m_variable->getValue().get());
+			if (identifier)
+				identifier->checkTypeRequirementsFromVariableDeclaration();
+			else
+				m_variable->getValue()->checkTypeRequirements();
+			TypePointer type = m_variable->getValue()->getType();
+			if (type->getCategory() == Type::Category::IntegerConstant)
+			{
+				auto intType = dynamic_pointer_cast<IntegerConstantType const>(type)->getIntegerType();
+				if (!intType)
+					BOOST_THROW_EXCEPTION(m_variable->getValue()->createTypeError("Invalid integer constant " + type->toString()));
+				type = intType;
+			}
+			else if (type->getCategory() == Type::Category::Void)
+				BOOST_THROW_EXCEPTION(m_variable->createTypeError("var cannot be void type"));
+			m_variable->setType(type);
+		}
+	}
+>>>>>>> implement overload resolution
 }
 
 void Assignment::checkTypeRequirements()
@@ -544,10 +596,16 @@ void BinaryOperation::checkTypeRequirements()
 
 void FunctionCall::checkTypeRequirements()
 {
-	m_expression->checkTypeRequirements();
+	// we need to check arguments' type first as their info will be used by m_express(Identifier).
 	for (ASTPointer<Expression> const& argument: m_arguments)
 		argument->checkTypeRequirements();
 
+	auto identifier = dynamic_cast<Identifier*>(m_expression.get());
+	if (identifier)
+		identifier->checkTypeRequirementsWithFunctionCall(*this);
+	else
+		m_expression->checkTypeRequirements();
+
 	Type const* expressionType = m_expression->getType().get();
 	if (isTypeConversion())
 	{
@@ -617,6 +675,19 @@ void FunctionCall::checkTypeRequirements()
 		else
 			m_type = functionType->getReturnParameterTypes().front();
 	}
+	else if (OverloadedFunctionType const* overloadedTypes = dynamic_cast<OverloadedFunctionType const*>(expressionType))
+	{
+		// this only applies to "x(3)" where x is assigned by "var x = f;" where f is an overloaded functions.
+		overloadedTypes->m_identifier->overloadResolution(*this);
+		FunctionType const* functionType = dynamic_cast<FunctionType const*>(overloadedTypes->m_identifier->getType().get());
+
+		// @todo actually the return type should be an anonymous struct,
+		// but we change it to the type of the first return value until we have structs
+		if (functionType->getReturnParameterTypes().empty())
+			m_type = make_shared<VoidType>();
+		else
+			m_type = functionType->getReturnParameterTypes().front();		
+	}
 	else
 		BOOST_THROW_EXCEPTION(createTypeError("Type is not callable."));
 }
@@ -709,16 +780,92 @@ void IndexAccess::checkTypeRequirements()
 	}
 }
 
+void Identifier::checkTypeRequirementsWithFunctionCall(FunctionCall const& _functionCall)
+{
+	solAssert(m_referencedDeclaration || !m_overloadedDeclarations.empty(), "Identifier not resolved.");
+
+	if (!m_referencedDeclaration)
+		overloadResolution(_functionCall);
+
+	checkTypeRequirements();
+}
+
+void Identifier::checkTypeRequirementsFromVariableDeclaration()
+{
+	solAssert(m_referencedDeclaration || !m_overloadedDeclarations.empty(), "Identifier not resolved.");
+
+	if (!m_referencedDeclaration)
+		m_type = make_shared<OverloadedFunctionType>(m_overloadedDeclarations, this);
+	else
+		checkTypeRequirements();
+
+	m_isLValue = true;
+}
+
 void Identifier::checkTypeRequirements()
 {
+	// var x = f; TODO!
 	solAssert(m_referencedDeclaration, "Identifier not resolved.");
 
 	m_isLValue = m_referencedDeclaration->isLValue();
+	if (m_isLValue)
+		std::cout << "Identifier: " << string(getName()) << " -> true" << std::endl;
+	else
+		std::cout << "Identifier: " << string(getName()) << " -> true" << std::endl;
 	m_type = m_referencedDeclaration->getType(m_currentContract);
 	if (!m_type)
 		BOOST_THROW_EXCEPTION(createTypeError("Declaration referenced before type could be determined."));
 }
 
+void Identifier::overloadResolution(FunctionCall const& _functionCall)
+{
+	solAssert(m_overloadedDeclarations.size() > 1, "FunctionIdentifier not resolved.");
+	solAssert(!m_referencedDeclaration, "Referenced declaration should be null before overload resolution.");
+
+	bool resolved = false;
+
+	std::vector<ASTPointer<Expression const>> arguments = _functionCall.getArguments();
+	std::vector<ASTPointer<ASTString>> const& argumentNames = _functionCall.getNames();
+
+	if (argumentNames.empty())
+	{
+		// positional arguments
+		std::vector<Declaration const*> possibles;
+		for (Declaration const* declaration: m_overloadedDeclarations)
+		{
+			TypePointer const& function = declaration->getType();
+			auto const& functionType = dynamic_cast<FunctionType const&>(*function);
+			TypePointers const& parameterTypes = functionType.getParameterTypes();
+
+			if (functionType.takesArbitraryParameters() ||
+				(arguments.size() == parameterTypes.size() &&
+				 std::equal(arguments.cbegin(), arguments.cend(), parameterTypes.cbegin(),
+							[](ASTPointer<Expression const> const& argument, TypePointer const& parameterType)
+							{
+								return argument->getType()->isImplicitlyConvertibleTo(*parameterType);
+							})))
+				possibles.push_back(declaration);			
+		}
+		std::cout << "possibles: " << possibles.size() << std::endl;
+		if (possibles.empty())
+			BOOST_THROW_EXCEPTION(createTypeError("Can't resolve identifier"));
+		else if (std::none_of(possibles.cbegin() + 1, possibles.cend(),
+			[&possibles](Declaration const* declaration)
+			{
+				return declaration->getScope() == possibles.front()->getScope();
+			}))
+				setReferencedDeclaration(*possibles.front());
+		else
+			BOOST_THROW_EXCEPTION(createTypeError("Can't resolve identifier"));
+	}
+	else
+	{
+		// named arguments
+		// TODO: don't support right now
+		// BOOST_THROW_EXCEPTION(createTypeError("Named arguments with overloaded functions are not supported yet."));
+	}
+}
+
 void ElementaryTypeNameExpression::checkTypeRequirements()
 {
 	m_type = make_shared<TypeType>(Type::fromElementaryTypeName(m_typeToken));
diff --git a/AST.h b/AST.h
index b21e505e..fa1d4a92 100644
--- a/AST.h
+++ b/AST.h
@@ -1134,8 +1134,8 @@ public:
 class Identifier: public PrimaryExpression
 {
 public:
-	Identifier(SourceLocation const& _location, ASTPointer<ASTString> const& _name, bool _isCallable):
-		PrimaryExpression(_location), m_name(_name), m_isCallable(_isCallable) {}
+	Identifier(SourceLocation const& _location, ASTPointer<ASTString> const& _name):
+		PrimaryExpression(_location), m_name(_name) {}
 	virtual void accept(ASTVisitor& _visitor) override;
 	virtual void accept(ASTConstVisitor& _visitor) const override;
 	virtual void checkTypeRequirements() override;
@@ -1151,9 +1151,15 @@ public:
 	Declaration const* getReferencedDeclaration() const { return m_referencedDeclaration; }
 	ContractDefinition const* getCurrentContract() const { return m_currentContract; }
 
-	bool isCallable() const { return m_isCallable; }
+	void setOverloadedDeclarations(std::set<Declaration const*> const& _declarations) { m_overloadedDeclarations = _declarations; }
+	std::set<Declaration const*> getOverloadedDeclarations() const { return m_overloadedDeclarations; }
 
+	void checkTypeRequirementsWithFunctionCall(FunctionCall const& _functionCall);
+	void checkTypeRequirementsFromVariableDeclaration();
+
+	void overloadResolution(FunctionCall const& _functionCall);
 private:
+
 	ASTPointer<ASTString> m_name;
 
 	/// Declaration the name refers to.
@@ -1161,7 +1167,8 @@ private:
 	/// Stores a reference to the current contract. This is needed because types of base contracts
 	/// change depending on the context.
 	ContractDefinition const* m_currentContract = nullptr;
-	bool m_isCallable = false;
+	/// A set of overloaded declarations, right now only FunctionDefinition has overloaded declarations.
+	std::set<Declaration const*> m_overloadedDeclarations;
 };
 
 /**
diff --git a/CompilerContext.cpp b/CompilerContext.cpp
index f787db7f..b12e0192 100644
--- a/CompilerContext.cpp
+++ b/CompilerContext.cpp
@@ -108,8 +108,8 @@ eth::AssemblyItem CompilerContext::getVirtualFunctionEntryLabel(FunctionDefiniti
 		for (ASTPointer<FunctionDefinition> const& function: contract->getDefinedFunctions())
 		{
 			if (!function->isConstructor() &&
-				dynamic_cast<FunctionType const&>(*function->getType()).getCanonicalSignature() ==
-				dynamic_cast<FunctionType const&>(*_function.getType()).getCanonicalSignature())
+				dynamic_cast<FunctionType const&>(*function->getType(contract)).getCanonicalSignature() ==
+				dynamic_cast<FunctionType const&>(*_function.getType(contract)).getCanonicalSignature())
 				return getFunctionEntryLabel(*function);
 		}
 	solAssert(false, "Virtual function " + _function.getName() + " not found.");
diff --git a/ExpressionCompiler.cpp b/ExpressionCompiler.cpp
index 3d7a2531..5e5442ba 100644
--- a/ExpressionCompiler.cpp
+++ b/ExpressionCompiler.cpp
@@ -822,7 +822,11 @@ bool ExpressionCompiler::visit(IndexAccess const& _indexAccess)
 void ExpressionCompiler::endVisit(Identifier const& _identifier)
 {
 	Declaration const* declaration = _identifier.getReferencedDeclaration();
-	if (MagicVariableDeclaration const* magicVar = dynamic_cast<MagicVariableDeclaration const*>(declaration))
+	if (declaration == nullptr)
+	{
+		// no-op
+	}
+	else if (MagicVariableDeclaration const* magicVar = dynamic_cast<MagicVariableDeclaration const*>(declaration))
 	{
 		if (magicVar->getType()->getCategory() == Type::Category::Contract)
 			// "this" or "super"
diff --git a/NameAndTypeResolver.cpp b/NameAndTypeResolver.cpp
index f6ee2f1d..c787ae6b 100644
--- a/NameAndTypeResolver.cpp
+++ b/NameAndTypeResolver.cpp
@@ -90,15 +90,15 @@ void NameAndTypeResolver::updateDeclaration(Declaration const& _declaration)
 	solAssert(_declaration.getScope() == nullptr, "Updated declaration outside global scope.");
 }
 
-Declaration const* NameAndTypeResolver::resolveName(ASTString const& _name, Declaration const* _scope) const
+std::set<Declaration const*> NameAndTypeResolver::resolveName(ASTString const& _name, Declaration const* _scope) const
 {
 	auto iterator = m_scopes.find(_scope);
 	if (iterator == end(m_scopes))
-		return nullptr;
+		return std::set<Declaration const*>({});
 	return iterator->second.resolveName(_name, false);
 }
 
-Declaration const* NameAndTypeResolver::getNameFromCurrentScope(ASTString const& _name, bool _recursive)
+std::set<Declaration const*> NameAndTypeResolver::getNameFromCurrentScope(ASTString const& _name, bool _recursive)
 {
 	return m_currentScope->resolveName(_name, _recursive);
 }
@@ -108,13 +108,11 @@ void NameAndTypeResolver::importInheritedScope(ContractDefinition const& _base)
 	auto iterator = m_scopes.find(&_base);
 	solAssert(iterator != end(m_scopes), "");
 	for (auto const& nameAndDeclaration: iterator->second.getDeclarations())
-	{
-		Declaration const* declaration = nameAndDeclaration.second;
-		// Import if it was declared in the base, is not the constructor and is visible in derived classes
-		if (declaration->getScope() == &_base && declaration->getName() != _base.getName() &&
-				declaration->isVisibleInDerivedContracts())
-			m_currentScope->registerDeclaration(*declaration);
-	}
+		for (auto const& declaration: nameAndDeclaration.second)
+			// Import if it was declared in the base, is not the constructor and is visible in derived classes
+			if (declaration->getScope() == &_base && declaration->getName() != _base.getName() &&
+					declaration->isVisibleInDerivedContracts())
+				m_currentScope->registerDeclaration(*declaration);
 }
 
 void NameAndTypeResolver::linearizeBaseContracts(ContractDefinition& _contract) const
@@ -361,24 +359,31 @@ bool ReferencesResolver::visit(Mapping&)
 
 bool ReferencesResolver::visit(UserDefinedTypeName& _typeName)
 {
-	Declaration const* declaration = m_resolver.getNameFromCurrentScope(_typeName.getName());
-	if (!declaration)
+	auto declarations = m_resolver.getNameFromCurrentScope(_typeName.getName());
+	if (declarations.empty())
 		BOOST_THROW_EXCEPTION(DeclarationError() << errinfo_sourceLocation(_typeName.getLocation())
 												 << errinfo_comment("Undeclared identifier."));
-	_typeName.setReferencedDeclaration(*declaration);
+	else if (declarations.size() > 1)
+		BOOST_THROW_EXCEPTION(DeclarationError() << errinfo_sourceLocation(_typeName.getLocation())
+												 << errinfo_comment("Duplicate identifier."));
+	else
+		_typeName.setReferencedDeclaration(**declarations.begin());
 	return false;
 }
 
 bool ReferencesResolver::visit(Identifier& _identifier)
 {
-	Declaration const* declaration = m_resolver.getNameFromCurrentScope(_identifier.getName());
-	if (!declaration)
+	auto declarations = m_resolver.getNameFromCurrentScope(_identifier.getName());
+	if (declarations.empty())
 		BOOST_THROW_EXCEPTION(DeclarationError() << errinfo_sourceLocation(_identifier.getLocation())
 												 << errinfo_comment("Undeclared identifier."));
-	_identifier.setReferencedDeclaration(*declaration, m_currentContract);
+	else if (declarations.size() == 1)
+		_identifier.setReferencedDeclaration(**declarations.begin(), m_currentContract);
+	else
+		// Duplicate declaration will be checked in checkTypeRequirements()
+		_identifier.setOverloadedDeclarations(declarations);
 	return false;
 }
 
-
 }
 }
diff --git a/NameAndTypeResolver.h b/NameAndTypeResolver.h
index 63b8ab63..82877617 100644
--- a/NameAndTypeResolver.h
+++ b/NameAndTypeResolver.h
@@ -56,11 +56,11 @@ public:
 	/// Resolves the given @a _name inside the scope @a _scope. If @a _scope is omitted,
 	/// the global scope is used (i.e. the one containing only the contract).
 	/// @returns a pointer to the declaration on success or nullptr on failure.
-	Declaration const* resolveName(ASTString const& _name, Declaration const* _scope = nullptr) const;
+	std::set<Declaration const*> resolveName(ASTString const& _name, Declaration const* _scope = nullptr) const;
 
 	/// Resolves a name in the "current" scope. Should only be called during the initial
 	/// resolving phase.
-	Declaration const* getNameFromCurrentScope(ASTString const& _name, bool _recursive = true);
+	std::set<Declaration const*> getNameFromCurrentScope(ASTString const& _name, bool _recursive = true);
 
 private:
 	void reset();
diff --git a/Parser.cpp b/Parser.cpp
index cecf772d..44d11159 100644
--- a/Parser.cpp
+++ b/Parser.cpp
@@ -837,14 +837,9 @@ ASTPointer<Expression> Parser::parsePrimaryExpression()
 		expression = nodeFactory.createNode<Literal>(token, getLiteralAndAdvance());
 		break;
 	case Token::Identifier:
-	{
 		nodeFactory.markEndPosition();
-		// if the next token is '(', this identifier looks like function call,
-		// it could be a contract, event etc.
-		bool isCallable = m_scanner->peekNextToken() == Token::LParen;
-		expression = nodeFactory.createNode<Identifier>(getLiteralAndAdvance(), isCallable);
+		expression = nodeFactory.createNode<Identifier>(getLiteralAndAdvance());
 		break;
-	}
 	case Token::LParen:
 	{
 		m_scanner->next();
diff --git a/Types.h b/Types.h
index 6cef8d64..5dd742ad 100644
--- a/Types.h
+++ b/Types.h
@@ -77,7 +77,7 @@ public:
 	enum class Category
 	{
 		Integer, IntegerConstant, Bool, Real, Array,
-		String, Contract, Struct, Function, Enum,
+		String, Contract, Struct, Function, OverloadedFunctions, Enum,
 		Mapping, Void, TypeType, Modifier, Magic
 	};
 
@@ -524,6 +524,19 @@ private:
 	Declaration const* m_declaration = nullptr;
 };
 
+class OverloadedFunctionType: public Type
+{
+public:
+	explicit OverloadedFunctionType(std::set<Declaration const*> const& _overloadedDeclarations, Identifier* _identifier):
+		m_overloadedDeclarations(_overloadedDeclarations), m_identifier(_identifier) {}
+	virtual Category getCategory() const override { return Category::OverloadedFunctions; }
+	virtual std::string toString() const override { return "OverloadedFunctions"; }
+
+// private:
+	std::set<Declaration const*> m_overloadedDeclarations;
+	Identifier * m_identifier;
+};
+
 /**
  * The type of a mapping, there is one distinct type per key/value type pair.
  */