Merge pull request #2722 from ethereum/statemutability

Introduce state mutability (to replace const/payable)

12 files changed, 141 insertions, 105 deletions

diff --git a/libsolidity/analysis/TypeChecker.cpp b/libsolidity/analysis/TypeChecker.cpp
index 8dd45a90..dbc95c4f 100644
--- a/libsolidity/analysis/TypeChecker.cpp
+++ b/libsolidity/analysis/TypeChecker.cpp
@@ -500,8 +500,6 @@ bool TypeChecker::visit(FunctionDefinition const& _function)
 			m_errorReporter.typeError(_function.location(), "Library functions cannot be payable.");
 		if (!_function.isConstructor() && !_function.isFallback() && !_function.isPartOfExternalInterface())
 			m_errorReporter.typeError(_function.location(), "Internal functions cannot be payable.");
-		if (_function.isDeclaredConst())
-			m_errorReporter.typeError(_function.location(), "Functions cannot be constant and payable at the same time.");
 	}
 	for (ASTPointer<VariableDeclaration> const& var: _function.parameters() + _function.returnParameters())
 	{
diff --git a/libsolidity/ast/AST.h b/libsolidity/ast/AST.h
index d32cf573..8a577c0c 100644
--- a/libsolidity/ast/AST.h
+++ b/libsolidity/ast/AST.h
@@ -28,6 +28,7 @@
 #include <libsolidity/ast/Types.h>
 #include <libsolidity/interface/Exceptions.h>
 #include <libsolidity/ast/ASTAnnotations.h>
+#include <libsolidity/ast/ASTEnums.h>
 
 #include <libevmasm/SourceLocation.h>
 #include <libevmasm/Instruction.h>
@@ -584,21 +585,19 @@ public:
 		SourceLocation const& _location,
 		ASTPointer<ASTString> const& _name,
 		Declaration::Visibility _visibility,
+		StateMutability _stateMutability,
 		bool _isConstructor,
 		ASTPointer<ASTString> const& _documentation,
 		ASTPointer<ParameterList> const& _parameters,
-		bool _isDeclaredConst,
 		std::vector<ASTPointer<ModifierInvocation>> const& _modifiers,
 		ASTPointer<ParameterList> const& _returnParameters,
-		bool _isPayable,
 		ASTPointer<Block> const& _body
 	):
 		CallableDeclaration(_location, _name, _visibility, _parameters, _returnParameters),
 		Documented(_documentation),
 		ImplementationOptional(_body != nullptr),
+		m_stateMutability(_stateMutability),
 		m_isConstructor(_isConstructor),
-		m_isDeclaredConst(_isDeclaredConst),
-		m_isPayable(_isPayable),
 		m_functionModifiers(_modifiers),
 		m_body(_body)
 	{}
@@ -606,10 +605,11 @@ public:
 	virtual void accept(ASTVisitor& _visitor) override;
 	virtual void accept(ASTConstVisitor& _visitor) const override;
 
+	StateMutability stateMutability() const { return m_stateMutability; }
 	bool isConstructor() const { return m_isConstructor; }
 	bool isFallback() const { return name().empty(); }
-	bool isDeclaredConst() const { return m_isDeclaredConst; }
-	bool isPayable() const { return m_isPayable; }
+	bool isDeclaredConst() const { return m_stateMutability == StateMutability::View; }
+	bool isPayable() const { return m_stateMutability == StateMutability::Payable; }
 	std::vector<ASTPointer<ModifierInvocation>> const& modifiers() const { return m_functionModifiers; }
 	std::vector<ASTPointer<VariableDeclaration>> const& returnParameters() const { return m_returnParameters->parameters(); }
 	Block const& body() const { solAssert(m_body, ""); return *m_body; }
@@ -634,9 +634,8 @@ public:
 	virtual FunctionDefinitionAnnotation& annotation() const override;
 
 private:
+	StateMutability m_stateMutability;
 	bool m_isConstructor;
-	bool m_isDeclaredConst;
-	bool m_isPayable;
 	std::vector<ASTPointer<ModifierInvocation>> m_functionModifiers;
 	ASTPointer<Block> m_body;
 };
@@ -896,11 +895,10 @@ public:
 		ASTPointer<ParameterList> const& _parameterTypes,
 		ASTPointer<ParameterList> const& _returnTypes,
 		Declaration::Visibility _visibility,
-		bool _isDeclaredConst,
-		bool _isPayable
+		StateMutability _stateMutability
 	):
 		TypeName(_location), m_parameterTypes(_parameterTypes), m_returnTypes(_returnTypes),
-		m_visibility(_visibility), m_isDeclaredConst(_isDeclaredConst), m_isPayable(_isPayable)
+		m_visibility(_visibility), m_stateMutability(_stateMutability)
 	{}
 	virtual void accept(ASTVisitor& _visitor) override;
 	virtual void accept(ASTConstVisitor& _visitor) const override;
@@ -914,15 +912,15 @@ public:
 	{
 		return m_visibility == Declaration::Visibility::Default ? Declaration::Visibility::Internal : m_visibility;
 	}
-	bool isDeclaredConst() const { return m_isDeclaredConst; }
-	bool isPayable() const { return m_isPayable; }
+	StateMutability stateMutability() const { return m_stateMutability; }
+	bool isDeclaredConst() const { return m_stateMutability == StateMutability::View; }
+	bool isPayable() const { return m_stateMutability == StateMutability::Payable; }
 
 private:
 	ASTPointer<ParameterList> m_parameterTypes;
 	ASTPointer<ParameterList> m_returnTypes;
 	Declaration::Visibility m_visibility;
-	bool m_isDeclaredConst;
-	bool m_isPayable;
+	StateMutability m_stateMutability;
 };
 
 /**
diff --git a/libsolidity/ast/ASTEnums.h b/libsolidity/ast/ASTEnums.h
new file mode 100644
index 00000000..f7c75878
--- /dev/null
+++ b/libsolidity/ast/ASTEnums.h
@@ -0,0 +1,52 @@
+/*
+    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/>.
+*/
+/**
+ * @date 2017
+ * Enums for AST classes.
+ */
+
+#pragma once
+
+#include <libsolidity/interface/Exceptions.h>
+
+#include <string>
+
+namespace dev
+{
+namespace solidity
+{
+
+// How a function can mutate the EVM state.
+enum class StateMutability { View, NonPayable, Payable };
+
+inline std::string stateMutabilityToString(StateMutability const& _stateMutability)
+{
+	switch(_stateMutability)
+	{
+	case StateMutability::View:
+		return "view";
+	case StateMutability::NonPayable:
+		return "nonpayable";
+	case StateMutability::Payable:
+		return "payable";
+	default:
+		solAssert(false, "Unknown state mutability.");
+	}
+}
+
+}
+}
diff --git a/libsolidity/ast/ASTForward.h b/libsolidity/ast/ASTForward.h
index cfeeaa58..15735368 100644
--- a/libsolidity/ast/ASTForward.h
+++ b/libsolidity/ast/ASTForward.h
@@ -95,6 +95,5 @@ using ASTPointer = std::shared_ptr<T>;
 
 using ASTString = std::string;
 
-
 }
 }
diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index a66ccda5..6c2e55f6 100644
--- a/libsolidity/ast/Types.cpp
+++ b/libsolidity/ast/Types.cpp
@@ -477,8 +477,8 @@ MemberList::MemberMap IntegerType::nativeMembers(ContractDefinition const*) cons
 	if (isAddress())
 		return {
 			{"balance", make_shared<IntegerType >(256)},
-			{"call", make_shared<FunctionType>(strings(), strings{"bool"}, FunctionType::Kind::BareCall, true, false, true)},
-			{"callcode", make_shared<FunctionType>(strings(), strings{"bool"}, FunctionType::Kind::BareCallCode, true, false, true)},
+			{"call", make_shared<FunctionType>(strings(), strings{"bool"}, FunctionType::Kind::BareCall, true, StateMutability::Payable)},
+			{"callcode", make_shared<FunctionType>(strings(), strings{"bool"}, FunctionType::Kind::BareCallCode, true, StateMutability::Payable)},
 			{"delegatecall", make_shared<FunctionType>(strings(), strings{"bool"}, FunctionType::Kind::BareDelegateCall, true)},
 			{"send", make_shared<FunctionType>(strings{"uint"}, strings{"bool"}, FunctionType::Kind::Send)},
 			{"transfer", make_shared<FunctionType>(strings{"uint"}, strings(), FunctionType::Kind::Transfer)}
@@ -2000,8 +2000,7 @@ TypePointer TupleType::closestTemporaryType(TypePointer const& _targetType) cons
 
 FunctionType::FunctionType(FunctionDefinition const& _function, bool _isInternal):
 	m_kind(_isInternal ? Kind::Internal : Kind::External),
-	m_isConstant(_function.isDeclaredConst()),
-	m_isPayable(_isInternal ? false : _function.isPayable()),
+	m_stateMutability(_function.stateMutability()),
 	m_declaration(&_function)
 {
 	TypePointers params;
@@ -2009,6 +2008,9 @@ FunctionType::FunctionType(FunctionDefinition const& _function, bool _isInternal
 	TypePointers retParams;
 	vector<string> retParamNames;
 
+	if (_isInternal && m_stateMutability == StateMutability::Payable)
+		m_stateMutability = StateMutability::NonPayable;
+
 	params.reserve(_function.parameters().size());
 	paramNames.reserve(_function.parameters().size());
 	for (ASTPointer<VariableDeclaration> const& var: _function.parameters())
@@ -2030,7 +2032,7 @@ FunctionType::FunctionType(FunctionDefinition const& _function, bool _isInternal
 }
 
 FunctionType::FunctionType(VariableDeclaration const& _varDecl):
-	m_kind(Kind::External), m_isConstant(true), m_declaration(&_varDecl)
+	m_kind(Kind::External), m_stateMutability(StateMutability::View), m_declaration(&_varDecl)
 {
 	TypePointers paramTypes;
 	vector<string> paramNames;
@@ -2090,7 +2092,7 @@ FunctionType::FunctionType(VariableDeclaration const& _varDecl):
 }
 
 FunctionType::FunctionType(EventDefinition const& _event):
-	m_kind(Kind::Event), m_isConstant(true), m_declaration(&_event)
+	m_kind(Kind::Event), m_stateMutability(StateMutability::View), m_declaration(&_event)
 {
 	TypePointers params;
 	vector<string> paramNames;
@@ -2107,14 +2109,10 @@ FunctionType::FunctionType(EventDefinition const& _event):
 
 FunctionType::FunctionType(FunctionTypeName const& _typeName):
 	m_kind(_typeName.visibility() == VariableDeclaration::Visibility::External ? Kind::External : Kind::Internal),
-	m_isConstant(_typeName.isDeclaredConst()),
-	m_isPayable(_typeName.isPayable())
+	m_stateMutability(_typeName.stateMutability())
 {
 	if (_typeName.isPayable())
-	{
 		solAssert(m_kind == Kind::External, "Internal payable function type used.");
-		solAssert(!m_isConstant, "Payable constant function");
-	}
 	for (auto const& t: _typeName.parameterTypes())
 	{
 		solAssert(t->annotation().type, "Type not set for parameter.");
@@ -2142,7 +2140,7 @@ FunctionTypePointer FunctionType::newExpressionType(ContractDefinition const& _c
 	FunctionDefinition const* constructor = _contract.constructor();
 	TypePointers parameters;
 	strings parameterNames;
-	bool payable = false;
+	StateMutability stateMutability = StateMutability::NonPayable;
 
 	if (constructor)
 	{
@@ -2151,7 +2149,8 @@ FunctionTypePointer FunctionType::newExpressionType(ContractDefinition const& _c
 			parameterNames.push_back(var->name());
 			parameters.push_back(var->annotation().type);
 		}
-		payable = constructor->isPayable();
+		if (constructor->isPayable())
+			stateMutability = StateMutability::Payable;
 	}
 	return make_shared<FunctionType>(
 		parameters,
@@ -2161,8 +2160,7 @@ FunctionTypePointer FunctionType::newExpressionType(ContractDefinition const& _c
 		Kind::Creation,
 		false,
 		nullptr,
-		false,
-		payable
+		stateMutability
 	);
 }
 
@@ -2241,8 +2239,8 @@ bool FunctionType::operator==(Type const& _other) const
 	FunctionType const& other = dynamic_cast<FunctionType const&>(_other);
 	if (
 		m_kind != other.m_kind ||
-		m_isConstant != other.isConstant() ||
-		m_isPayable != other.isPayable() ||
+		isConstant() != other.isConstant() ||
+		isPayable() != other.isPayable() ||
 		m_parameterTypes.size() != other.m_parameterTypes.size() ||
 		m_returnParameterTypes.size() != other.m_returnParameterTypes.size()
 	)
@@ -2304,9 +2302,9 @@ string FunctionType::toString(bool _short) const
 	for (auto it = m_parameterTypes.begin(); it != m_parameterTypes.end(); ++it)
 		name += (*it)->toString(_short) + (it + 1 == m_parameterTypes.end() ? "" : ",");
 	name += ")";
-	if (m_isConstant)
+	if (isConstant())
 		name += " constant";
-	if (m_isPayable)
+	if (isPayable())
 		name += " payable";
 	if (m_kind == Kind::External)
 		name += " external";
@@ -2420,8 +2418,7 @@ FunctionTypePointer FunctionType::interfaceFunctionType() const
 		m_kind,
 		m_arbitraryParameters,
 		m_declaration,
-		m_isConstant,
-		m_isPayable
+		m_stateMutability
 	);
 }
 
@@ -2438,7 +2435,7 @@ MemberList::MemberMap FunctionType::nativeMembers(ContractDefinition const*) con
 		MemberList::MemberMap members;
 		if (m_kind != Kind::BareDelegateCall && m_kind != Kind::DelegateCall)
 		{
-			if (m_isPayable)
+			if (isPayable())
 				members.push_back(MemberList::Member(
 					"value",
 					make_shared<FunctionType>(
@@ -2449,8 +2446,7 @@ MemberList::MemberMap FunctionType::nativeMembers(ContractDefinition const*) con
 						Kind::SetValue,
 						false,
 						nullptr,
-						false,
-						false,
+						StateMutability::NonPayable,
 						m_gasSet,
 						m_valueSet
 					)
@@ -2467,8 +2463,7 @@ MemberList::MemberMap FunctionType::nativeMembers(ContractDefinition const*) con
 					Kind::SetGas,
 					false,
 					nullptr,
-					false,
-					false,
+					StateMutability::NonPayable,
 					m_gasSet,
 					m_valueSet
 				)
@@ -2604,8 +2599,7 @@ TypePointer FunctionType::copyAndSetGasOrValue(bool _setGas, bool _setValue) con
 		m_kind,
 		m_arbitraryParameters,
 		m_declaration,
-		m_isConstant,
-		m_isPayable,
+		m_stateMutability,
 		m_gasSet || _setGas,
 		m_valueSet || _setValue,
 		m_bound
@@ -2654,8 +2648,7 @@ FunctionTypePointer FunctionType::asMemberFunction(bool _inLibrary, bool _bound)
 		kind,
 		m_arbitraryParameters,
 		m_declaration,
-		m_isConstant,
-		m_isPayable,
+		m_stateMutability,
 		m_gasSet,
 		m_valueSet,
 		_bound
diff --git a/libsolidity/ast/Types.h b/libsolidity/ast/Types.h
index 8c9232c6..56546a82 100644
--- a/libsolidity/ast/Types.h
+++ b/libsolidity/ast/Types.h
@@ -24,6 +24,7 @@
 
 #include <libsolidity/interface/Exceptions.h>
 #include <libsolidity/ast/ASTForward.h>
+#include <libsolidity/ast/ASTEnums.h>
 #include <libsolidity/parsing/Token.h>
 
 #include <libdevcore/Common.h>
@@ -889,8 +890,7 @@ public:
 		strings const& _returnParameterTypes,
 		Kind _kind = Kind::Internal,
 		bool _arbitraryParameters = false,
-		bool _constant = false,
-		bool _payable = false
+		StateMutability _stateMutability = StateMutability::NonPayable
 	): FunctionType(
 		parseElementaryTypeVector(_parameterTypes),
 		parseElementaryTypeVector(_returnParameterTypes),
@@ -899,8 +899,7 @@ public:
 		_kind,
 		_arbitraryParameters,
 		nullptr,
-		_constant,
-		_payable
+		_stateMutability
 	)
 	{
 	}
@@ -917,8 +916,7 @@ public:
 		Kind _kind = Kind::Internal,
 		bool _arbitraryParameters = false,
 		Declaration const* _declaration = nullptr,
-		bool _isConstant = false,
-		bool _isPayable = false,
+		StateMutability _stateMutability = StateMutability::NonPayable,
 		bool _gasSet = false,
 		bool _valueSet = false,
 		bool _bound = false
@@ -928,12 +926,11 @@ public:
 		m_parameterNames(_parameterNames),
 		m_returnParameterNames(_returnParameterNames),
 		m_kind(_kind),
+		m_stateMutability(_stateMutability),
 		m_arbitraryParameters(_arbitraryParameters),
 		m_gasSet(_gasSet),
 		m_valueSet(_valueSet),
 		m_bound(_bound),
-		m_isConstant(_isConstant),
-		m_isPayable(_isPayable),
 		m_declaration(_declaration)
 	{
 		solAssert(
@@ -985,6 +982,7 @@ public:
 	/// @returns true if the ABI is used for this call (only meaningful for external calls)
 	bool isBareCall() const;
 	Kind const& kind() const { return m_kind; }
+	StateMutability stateMutability() const { return m_stateMutability; }
 	/// @returns the external signature of this function type given the function name
 	std::string externalSignature() const;
 	/// @returns the external identifier of this function (the hash of the signature).
@@ -995,12 +993,12 @@ public:
 		return *m_declaration;
 	}
 	bool hasDeclaration() const { return !!m_declaration; }
-	bool isConstant() const { return m_isConstant; }
+	bool isConstant() const { return m_stateMutability == StateMutability::View; }
 	/// @returns true if the the result of this function only depends on its arguments
 	/// and it does not modify the state.
 	/// Currently, this will only return true for internal functions like keccak and ecrecover.
 	bool isPure() const;
-	bool isPayable() const { return m_isPayable; }
+	bool isPayable() const { return m_stateMutability == StateMutability::Payable; }
 	/// @return A shared pointer of an ASTString.
 	/// Can contain a nullptr in which case indicates absence of documentation
 	ASTPointer<ASTString> documentation() const;
@@ -1033,13 +1031,12 @@ private:
 	std::vector<std::string> m_parameterNames;
 	std::vector<std::string> m_returnParameterNames;
 	Kind const m_kind;
+	StateMutability m_stateMutability = StateMutability::NonPayable;
 	/// true if the function takes an arbitrary number of arguments of arbitrary types
 	bool const m_arbitraryParameters = false;
 	bool const m_gasSet = false; ///< true iff the gas value to be used is on the stack
 	bool const m_valueSet = false; ///< true iff the value to be sent is on the stack
 	bool const m_bound = false; ///< true iff the function is called as arg1.fun(arg2, ..., argn)
-	bool m_isConstant = false;
-	bool m_isPayable = false;
 	Declaration const* m_declaration = nullptr;
 };
 
diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp
index 521d485f..55d35c44 100644
--- a/libsolidity/codegen/ExpressionCompiler.cpp
+++ b/libsolidity/codegen/ExpressionCompiler.cpp
@@ -645,8 +645,7 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 					FunctionType::Kind::BareCall,
 					false,
 					nullptr,
-					false,
-					false,
+					StateMutability::NonPayable,
 					true,
 					true
 				),
diff --git a/libsolidity/parsing/Parser.cpp b/libsolidity/parsing/Parser.cpp
index 066e3a29..32bd0966 100644
--- a/libsolidity/parsing/Parser.cpp
+++ b/libsolidity/parsing/Parser.cpp
@@ -307,6 +307,19 @@ Declaration::Visibility Parser::parseVisibilitySpecifier(Token::Value _token)
 	return visibility;
 }
 
+StateMutability Parser::parseStateMutability(Token::Value _token)
+{
+	StateMutability stateMutability(StateMutability::NonPayable);
+	if (_token == Token::Payable)
+		stateMutability = StateMutability::Payable;
+	else if (_token == Token::Constant)
+		stateMutability = StateMutability::View;
+	else
+		solAssert(false, "Invalid state mutability specifier.");
+	m_scanner->next();
+	return stateMutability;
+}
+
 Parser::FunctionHeaderParserResult Parser::parseFunctionHeader(bool _forceEmptyName, bool _allowModifiers)
 {
 	FunctionHeaderParserResult result;
@@ -321,23 +334,7 @@ Parser::FunctionHeaderParserResult Parser::parseFunctionHeader(bool _forceEmptyN
 	while (true)
 	{
 		Token::Value token = m_scanner->currentToken();
-		if (token == Token::Constant)
-		{
-			if (result.isDeclaredConst)
-				parserError(string("Multiple \"constant\" specifiers."));
-
-			result.isDeclaredConst = true;
-			m_scanner->next();
-		}
-		else if (m_scanner->currentToken() == Token::Payable)
-		{
-			if (result.isPayable)
-				parserError(string("Multiple \"payable\" specifiers."));
-
-			result.isPayable = true;
-			m_scanner->next();
-		}
-		else if (_allowModifiers && token == Token::Identifier)
+		if (_allowModifiers && token == Token::Identifier)
 		{
 			// This can either be a modifier (function declaration) or the name of the
 			// variable (function type name plus variable).
@@ -364,6 +361,20 @@ Parser::FunctionHeaderParserResult Parser::parseFunctionHeader(bool _forceEmptyN
 			else
 				result.visibility = parseVisibilitySpecifier(token);
 		}
+		else if (Token::isStateMutabilitySpecifier(token))
+		{
+			if (result.stateMutability != StateMutability::NonPayable)
+			{
+				parserError(string(
+					"State mutability already specified as \"" +
+					stateMutabilityToString(result.stateMutability) +
+					"\"."
+				));
+				m_scanner->next();
+			}
+			else
+				result.stateMutability = parseStateMutability(token);
+		}
 		else
 			break;
 	}
@@ -408,13 +419,12 @@ ASTPointer<ASTNode> Parser::parseFunctionDefinitionOrFunctionTypeStateVariable(A
 		return nodeFactory.createNode<FunctionDefinition>(
 			header.name,
 			header.visibility,
+			header.stateMutability,
 			c_isConstructor,
 			docstring,
 			header.parameters,
-			header.isDeclaredConst,
 			header.modifiers,
 			header.returnParameters,
-			header.isPayable,
 			block
 		);
 	}
@@ -425,8 +435,7 @@ ASTPointer<ASTNode> Parser::parseFunctionDefinitionOrFunctionTypeStateVariable(A
 			header.parameters,
 			header.returnParameters,
 			header.visibility,
-			header.isDeclaredConst,
-			header.isPayable
+			header.stateMutability
 		);
 		type = parseTypeNameSuffix(type, nodeFactory);
 		VarDeclParserOptions options;
@@ -751,8 +760,7 @@ ASTPointer<FunctionTypeName> Parser::parseFunctionType()
 		header.parameters,
 		header.returnParameters,
 		header.visibility,
-		header.isDeclaredConst,
-		header.isPayable
+		header.stateMutability
 	);
 }
 
diff --git a/libsolidity/parsing/Parser.h b/libsolidity/parsing/Parser.h
index 82ab91a6..97e60baa 100644
--- a/libsolidity/parsing/Parser.h
+++ b/libsolidity/parsing/Parser.h
@@ -60,8 +60,7 @@ private:
 		ASTPointer<ParameterList> parameters;
 		ASTPointer<ParameterList> returnParameters;
 		Declaration::Visibility visibility = Declaration::Visibility::Default;
-		bool isDeclaredConst = false;
-		bool isPayable = false;
+		StateMutability stateMutability = StateMutability::NonPayable;
 		std::vector<ASTPointer<ModifierInvocation>> modifiers;
 	};
 
@@ -73,7 +72,7 @@ private:
 	ASTPointer<ContractDefinition> parseContractDefinition(Token::Value _expectedKind);
 	ASTPointer<InheritanceSpecifier> parseInheritanceSpecifier();
 	Declaration::Visibility parseVisibilitySpecifier(Token::Value _token);
-	std::string visibilitySpecifierName(Declaration::Visibility _visibility);
+	StateMutability parseStateMutability(Token::Value _token);
 	FunctionHeaderParserResult parseFunctionHeader(bool _forceEmptyName, bool _allowModifiers);
 	ASTPointer<ASTNode> parseFunctionDefinitionOrFunctionTypeStateVariable(ASTString const* _contractName);
 	ASTPointer<FunctionDefinition> parseFunctionDefinition(ASTString const* _contractName);
diff --git a/libsolidity/parsing/Token.h b/libsolidity/parsing/Token.h
index 468cbcb7..efbe5e9e 100644
--- a/libsolidity/parsing/Token.h
+++ b/libsolidity/parsing/Token.h
@@ -290,6 +290,7 @@ public:
 	static bool isVisibilitySpecifier(Value op) { return isVariableVisibilitySpecifier(op) || op == External; }
 	static bool isVariableVisibilitySpecifier(Value op) { return op == Public || op == Private || op == Internal; }
 	static bool isLocationSpecifier(Value op) { return op == Memory || op == Storage; }
+	static bool isStateMutabilitySpecifier(Value op) { return op == Constant || op == Payable; }
 	static bool isEtherSubdenomination(Value op) { return op == SubWei || op == SubSzabo || op == SubFinney || op == SubEther; }
 	static bool isTimeSubdenomination(Value op) { return op == SubSecond || op == SubMinute || op == SubHour || op == SubDay || op == SubWeek || op == SubYear; }
 	static bool isReservedKeyword(Value op) { return (Abstract <= op && op <= TypeOf); }
diff --git a/test/libsolidity/SolidityNameAndTypeResolution.cpp b/test/libsolidity/SolidityNameAndTypeResolution.cpp
index 13843afa..51d60596 100644
--- a/test/libsolidity/SolidityNameAndTypeResolution.cpp
+++ b/test/libsolidity/SolidityNameAndTypeResolution.cpp
@@ -4771,15 +4771,6 @@ BOOST_AUTO_TEST_CASE(function_variable_mixin)
        CHECK_ERROR(text, DeclarationError, "Identifier already declared.");
 }
 
-
-BOOST_AUTO_TEST_CASE(payable_constant_conflict)
-{
-	char const* text = R"(
-		contract C { function f() payable constant {} }
-	)";
-	CHECK_ERROR(text, TypeError, "Functions cannot be constant and payable at the same time.");
-}
-
 BOOST_AUTO_TEST_CASE(calling_payable)
 {
 	char const* text = R"(
diff --git a/test/libsolidity/SolidityParser.cpp b/test/libsolidity/SolidityParser.cpp
index 3890ca21..75cad8d9 100644
--- a/test/libsolidity/SolidityParser.cpp
+++ b/test/libsolidity/SolidityParser.cpp
@@ -906,22 +906,23 @@ BOOST_AUTO_TEST_CASE(multiple_visibility_specifiers)
 	CHECK_PARSE_ERROR(text, "Visibility already specified as \"private\".");
 }
 
-BOOST_AUTO_TEST_CASE(multiple_payable_specifiers)
+BOOST_AUTO_TEST_CASE(multiple_statemutability_specifiers)
 {
 	char const* text = R"(
 		contract c {
 			function f() payable payable {}
 		})";
-	CHECK_PARSE_ERROR(text, "Multiple \"payable\" specifiers.");
-}
-
-BOOST_AUTO_TEST_CASE(multiple_constant_specifiers)
-{
-	char const* text = R"(
+	CHECK_PARSE_ERROR(text, "State mutability already specified as \"payable\".");
+	text = R"(
 		contract c {
 			function f() constant constant {}
 		})";
-	CHECK_PARSE_ERROR(text, "Multiple \"constant\" specifiers.");
+	CHECK_PARSE_ERROR(text, "State mutability already specified as \"view\".");
+	text = R"(
+		contract c {
+			function f() payable constant {}
+		})";
+	CHECK_PARSE_ERROR(text, "State mutability already specified as \"payable\".");
 }
 
 BOOST_AUTO_TEST_CASE(literal_constants_with_ether_subdenominations)