Added the using x for y directive.

libsolidity/analysis/NameAndTypeResolver.h

@@ -160,8 +160,8 @@ private:
 	void fatalDeclarationError(SourceLocation _sourceLocation, std::string const& _description);
 
 	std::map<ASTNode const*, DeclarationContainer>& m_scopes;
-	Declaration const* m_currentScope;
+	Declaration const* m_currentScope = nullptr;
-	VariableScope* m_currentFunction;
+	VariableScope* m_currentFunction = nullptr;
 	ErrorList& m_errors;
 };
 

libsolidity/analysis/TypeChecker.cpp

@@ -356,7 +356,16 @@ void TypeChecker::endVisit(InheritanceSpecifier const& _inheritance)
 				" to " +
 				parameterTypes[i]->toString() +
 				" requested."
-			);
+						);
+}
+
+void TypeChecker::endVisit(UsingForDirective const& _usingFor)
+{
+	ContractDefinition const* library = dynamic_cast<ContractDefinition const*>(
+		_usingFor.libraryName().annotation().referencedDeclaration
+	);
+	if (!library || !library->isLibrary())
+		typeError(_usingFor.libraryName().location(), "Library name expected.");
 }
 
 bool TypeChecker::visit(StructDefinition const& _struct)

libsolidity/analysis/TypeChecker.h

@@ -76,6 +76,7 @@ private:
 	void checkLibraryRequirements(ContractDefinition const& _contract);
 
 	virtual void endVisit(InheritanceSpecifier const& _inheritance) override;
+	virtual void endVisit(UsingForDirective const& _usingFor) override;
 	virtual bool visit(StructDefinition const& _struct) override;
 	virtual bool visit(FunctionDefinition const& _function) override;
 	virtual bool visit(VariableDeclaration const& _variable) override;

libsolidity/ast/AST.h

@@ -335,6 +335,33 @@ private:
 	std::vector<ASTPointer<Expression>> m_arguments;
 };
 
+/**
+ * `using LibraryName for uint` will attach all functions from the library LibraryName
+ * to `uint` if the first parameter matches the type. `using LibraryName for *` attaches
+ * the function to any matching type.
+ */
+class UsingForDirective: public ASTNode
+{
+public:
+	UsingForDirective(
+		SourceLocation const& _location,
+		ASTPointer<Identifier> const& _libraryName,
+		ASTPointer<TypeName> const& _typeName
+	):
+		ASTNode(_location), m_libraryName(_libraryName), m_typeName(_typeName) {}
+
+	virtual void accept(ASTVisitor& _visitor) override;
+	virtual void accept(ASTConstVisitor& _visitor) const override;
+
+	Identifier const& libraryName() const { return *m_libraryName; }
+	/// @returns the type name the library is attached to, null for `*`.
+	TypeName const* typeName() const { return m_typeName.get(); }
+
+private:
+	ASTPointer<Identifier> m_libraryName;
+	ASTPointer<TypeName> m_typeName;
+};
+
 class StructDefinition: public Declaration
 {
 public:

libsolidity/ast/ASTVisitor.h

@@ -47,6 +47,7 @@ public:
 	virtual bool visit(ImportDirective& _node) { return visitNode(_node); }
 	virtual bool visit(ContractDefinition& _node) { return visitNode(_node); }
 	virtual bool visit(InheritanceSpecifier& _node) { return visitNode(_node); }
+	virtual bool visit(UsingForDirective& _node) { return visitNode(_node); }
 	virtual bool visit(StructDefinition& _node) { return visitNode(_node); }
 	virtual bool visit(EnumDefinition& _node) { return visitNode(_node); }
 	virtual bool visit(EnumValue& _node) { return visitNode(_node); }
@@ -88,6 +89,7 @@ public:
 	virtual void endVisit(ImportDirective& _node) { endVisitNode(_node); }
 	virtual void endVisit(ContractDefinition& _node) { endVisitNode(_node); }
 	virtual void endVisit(InheritanceSpecifier& _node) { endVisitNode(_node); }
+	virtual void endVisit(UsingForDirective& _node) { endVisitNode(_node); }
 	virtual void endVisit(StructDefinition& _node) { endVisitNode(_node); }
 	virtual void endVisit(EnumDefinition& _node) { endVisitNode(_node); }
 	virtual void endVisit(EnumValue& _node) { endVisitNode(_node); }
@@ -142,6 +144,7 @@ public:
 	virtual bool visit(ContractDefinition const& _node) { return visitNode(_node); }
 	virtual bool visit(InheritanceSpecifier const& _node) { return visitNode(_node); }
 	virtual bool visit(StructDefinition const& _node) { return visitNode(_node); }
+	virtual bool visit(UsingForDirective const& _node) { return visitNode(_node); }
 	virtual bool visit(EnumDefinition const& _node) { return visitNode(_node); }
 	virtual bool visit(EnumValue const& _node) { return visitNode(_node); }
 	virtual bool visit(ParameterList const& _node) { return visitNode(_node); }
@@ -182,6 +185,7 @@ public:
 	virtual void endVisit(ImportDirective const& _node) { endVisitNode(_node); }
 	virtual void endVisit(ContractDefinition const& _node) { endVisitNode(_node); }
 	virtual void endVisit(InheritanceSpecifier const& _node) { endVisitNode(_node); }
+	virtual void endVisit(UsingForDirective const& _node) { endVisitNode(_node); }
 	virtual void endVisit(StructDefinition const& _node) { endVisitNode(_node); }
 	virtual void endVisit(EnumDefinition const& _node) { endVisitNode(_node); }
 	virtual void endVisit(EnumValue const& _node) { endVisitNode(_node); }

libsolidity/ast/AST_accept.h

@@ -123,6 +123,28 @@ void EnumValue::accept(ASTConstVisitor& _visitor) const
 	_visitor.endVisit(*this);
 }
 
+void UsingForDirective::accept(ASTVisitor& _visitor)
+{
+	if (_visitor.visit(*this))
+	{
+		if (m_libraryName)
+			m_libraryName->accept(_visitor);
+		m_typeName->accept(_visitor);
+	}
+	_visitor.endVisit(*this);
+}
+
+void UsingForDirective::accept(ASTConstVisitor& _visitor) const
+{
+	if (_visitor.visit(*this))
+	{
+		if (m_libraryName)
+			m_libraryName->accept(_visitor);
+		m_typeName->accept(_visitor);
+	}
+	_visitor.endVisit(*this);
+}
+
 void StructDefinition::accept(ASTVisitor& _visitor)
 {
 	if (_visitor.visit(*this))

libsolidity/parsing/Parser.cpp

@@ -168,6 +168,8 @@ ASTPointer<ContractDefinition> Parser::parseContractDefinition(bool _isLibrary)
 			subNodes.push_back(parseModifierDefinition());
 		else if (currentTokenValue == Token::Event)
 			subNodes.push_back(parseEventDefinition());
+		else if (currentTokenValue == Token::Using)
+			subNodes.push_back(parseUsingDirective());
 		else
 			fatalParserError(std::string("Function, variable, struct or modifier declaration expected."));
 	}
@@ -475,6 +477,24 @@ ASTPointer<EventDefinition> Parser::parseEventDefinition()
 	return nodeFactory.createNode<EventDefinition>(name, docstring, parameters, anonymous);
 }
 
+ASTPointer<UsingForDirective> Parser::parseUsingDirective()
+{
+	ASTNodeFactory nodeFactory(*this);
+
+	expectToken(Token::Using);
+	//@todo this should actually parse a full path.
+	ASTPointer<Identifier> library(parseIdentifier());
+	ASTPointer<TypeName> typeName;
+	expectToken(Token::For);
+	if (m_scanner->currentToken() == Token::Mul)
+		m_scanner->next();
+	else
+		typeName = parseTypeName(false);
+	nodeFactory.markEndPosition();
+	expectToken(Token::Semicolon);
+	return nodeFactory.createNode<UsingForDirective>(library, typeName);
+}
+
 ASTPointer<ModifierInvocation> Parser::parseModifierInvocation()
 {
 	ASTNodeFactory nodeFactory(*this);

libsolidity/parsing/Parser.h

@@ -74,6 +74,7 @@ private:
 	);
 	ASTPointer<ModifierDefinition> parseModifierDefinition();
 	ASTPointer<EventDefinition> parseEventDefinition();
+	ASTPointer<UsingForDirective> parseUsingDirective();
 	ASTPointer<ModifierInvocation> parseModifierInvocation();
 	ASTPointer<Identifier> parseIdentifier();
 	ASTPointer<TypeName> parseTypeName(bool _allowVar);

test/libsolidity/SolidityNameAndTypeResolution.cpp

@@ -2529,6 +2529,28 @@ BOOST_AUTO_TEST_CASE(member_access_parser_ambiguity)
 	BOOST_CHECK(success(text));
 }
 
+BOOST_AUTO_TEST_CASE(using_for_library)
+{
+	char const* text = R"(
+		library D { }
+		contract C {
+			using D for uint;
+		}
+	)";
+	BOOST_CHECK(success(text));
+}
+
+BOOST_AUTO_TEST_CASE(using_for_not_library)
+{
+	char const* text = R"(
+		contract D { }
+		contract C {
+			using D for uint;
+		}
+	)";
+	BOOST_CHECK(expectError(text) == Error::Type::TypeError);
+}
+
 BOOST_AUTO_TEST_CASE(create_memory_arrays)
 {
 	char const* text = R"(

test/libsolidity/SolidityParser.cpp

@@ -1032,6 +1032,21 @@ BOOST_AUTO_TEST_CASE(member_access_parser_ambiguity)
 	BOOST_CHECK(successParse(text));
 }
 
+BOOST_AUTO_TEST_CASE(using_for)
+{
+	char const* text = R"(
+		contract C {
+			struct s { uint a; }
+			using LibraryName for uint;
+			using Library2 for *;
+			using Lib for s;
+			function f() {
+			}
+		}
+	)";
+	BOOST_CHECK(successParse(text));
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }