Syntax for meta type information.

8 files changed, 113 insertions, 11 deletions

diff --git a/libsolidity/analysis/GlobalContext.cpp b/libsolidity/analysis/GlobalContext.cpp
index cd5fe07d..2276d783 100644
--- a/libsolidity/analysis/GlobalContext.cpp
+++ b/libsolidity/analysis/GlobalContext.cpp
@@ -61,7 +61,14 @@ m_magicVariables(vector<shared_ptr<MagicVariableDeclaration const>>{
 	make_shared<MagicVariableDeclaration>("sha256", make_shared<FunctionType>(strings{"bytes memory"}, strings{"bytes32"}, FunctionType::Kind::SHA256, false, StateMutability::Pure)),
 	make_shared<MagicVariableDeclaration>("sha3", make_shared<FunctionType>(strings{"bytes memory"}, strings{"bytes32"}, FunctionType::Kind::KECCAK256, false, StateMutability::Pure)),
 	make_shared<MagicVariableDeclaration>("suicide", make_shared<FunctionType>(strings{"address payable"}, strings{}, FunctionType::Kind::Selfdestruct)),
-	make_shared<MagicVariableDeclaration>("tx", make_shared<MagicType>(MagicType::Kind::Transaction))
+	make_shared<MagicVariableDeclaration>("tx", make_shared<MagicType>(MagicType::Kind::Transaction)),
+	make_shared<MagicVariableDeclaration>("type", make_shared<FunctionType>(
+		strings{"address"} /* accepts any contract type, handled by the type checker */,
+		strings{} /* returns a MagicType, handled by the type checker */,
+		FunctionType::Kind::MetaType,
+		false,
+		StateMutability::Pure
+	)),
 })
 {
 }
diff --git a/libsolidity/analysis/TypeChecker.cpp b/libsolidity/analysis/TypeChecker.cpp
index 507a2c94..4cdfcc0c 100644
--- a/libsolidity/analysis/TypeChecker.cpp
+++ b/libsolidity/analysis/TypeChecker.cpp
@@ -199,6 +199,38 @@ TypePointers TypeChecker::typeCheckABIDecodeAndRetrieveReturnType(FunctionCall c
 	return components;
 }
 
+TypePointers TypeChecker::typeCheckMetaTypeFunctionAndRetrieveReturnType(FunctionCall const& _functionCall)
+{
+	vector<ASTPointer<Expression const>> arguments = _functionCall.arguments();
+	if (arguments.size() != 1)
+	{
+		m_errorReporter.typeError(
+			_functionCall.location(),
+			"This function takes one argument, but " +
+			toString(arguments.size()) +
+			" were provided."
+		);
+		return {};
+	}
+	TypePointer firstArgType = type(*arguments.front());
+	if (
+		firstArgType->category() != Type::Category::TypeType ||
+		dynamic_cast<TypeType const&>(*firstArgType).actualType()->category() != TypeType::Category::Contract
+	)
+	{
+		m_errorReporter.typeError(
+			arguments.front()->location(),
+			"Invalid type for argument in function call. "
+			"Contract type required, but " +
+			type(*arguments.front())->toString(true) +
+			" provided."
+		);
+		return {};
+	}
+
+	return {MagicType::metaType(dynamic_cast<TypeType const&>(*firstArgType).actualType())};
+}
+
 void TypeChecker::endVisit(InheritanceSpecifier const& _inheritance)
 {
 	auto base = dynamic_cast<ContractDefinition const*>(&dereference(_inheritance.name()));
@@ -1822,6 +1854,9 @@ bool TypeChecker::visit(FunctionCall const& _functionCall)
 			returnTypes = functionType->returnParameterTypes();
 			break;
 		}
+		case FunctionType::Kind::MetaType:
+			returnTypes = typeCheckMetaTypeFunctionAndRetrieveReturnType(_functionCall);
+			break;
 		default:
 		{
 			typeCheckFunctionCall(_functionCall, functionType);
@@ -2062,8 +2097,13 @@ bool TypeChecker::visit(MemberAccess const& _memberAccess)
 		if (tt->actualType()->category() == Type::Category::Enum)
 			annotation.isPure = true;
 	if (auto magicType = dynamic_cast<MagicType const*>(exprType.get()))
+	{
 		if (magicType->kind() == MagicType::Kind::ABI)
 			annotation.isPure = true;
+		else if (magicType->kind() == MagicType::Kind::MetaType)
+			if (memberName == "creationCode" || memberName == "runtimeCode")
+				annotation.isPure = true;
+	}
 
 	return false;
 }
diff --git a/libsolidity/analysis/TypeChecker.h b/libsolidity/analysis/TypeChecker.h
index b60c571a..d5f3645c 100644
--- a/libsolidity/analysis/TypeChecker.h
+++ b/libsolidity/analysis/TypeChecker.h
@@ -81,6 +81,8 @@ private:
 		bool _abiEncoderV2
 	);
 
+	TypePointers typeCheckMetaTypeFunctionAndRetrieveReturnType(FunctionCall const& _functionCall);
+
 	/// Performs type checks and determines result types for type conversion FunctionCall nodes.
 	TypePointer typeCheckTypeConversionAndRetrieveReturnType(
 		FunctionCall const& _functionCall
diff --git a/libsolidity/analysis/ViewPureChecker.cpp b/libsolidity/analysis/ViewPureChecker.cpp
index eb019481..7df7ac17 100644
--- a/libsolidity/analysis/ViewPureChecker.cpp
+++ b/libsolidity/analysis/ViewPureChecker.cpp
@@ -338,7 +338,9 @@ void ViewPureChecker::endVisit(MemberAccess const& _memberAccess)
 			{MagicType::Kind::ABI, "encodeWithSignature"},
 			{MagicType::Kind::Block, "blockhash"},
 			{MagicType::Kind::Message, "data"},
-			{MagicType::Kind::Message, "sig"}
+			{MagicType::Kind::Message, "sig"},
+			{MagicType::Kind::MetaType, "creationCode"},
+			{MagicType::Kind::MetaType, "runtimeCode"}
 		};
 		set<MagicMember> static const payableMembers{
 			{MagicType::Kind::Message, "value"}
diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index cc978b4a..20859d28 100644
--- a/libsolidity/ast/Types.cpp
+++ b/libsolidity/ast/Types.cpp
@@ -2626,6 +2626,7 @@ string FunctionType::richIdentifier() const
 	case Kind::ABIEncodeWithSelector: id += "abiencodewithselector"; break;
 	case Kind::ABIEncodeWithSignature: id += "abiencodewithsignature"; break;
 	case Kind::ABIDecode: id += "abidecode"; break;
+	case Kind::MetaType: id += "metatype"; break;
 	}
 	id += "_" + stateMutabilityToString(m_stateMutability);
 	id += identifierList(m_parameterTypes) + "returns" + identifierList(m_returnParameterTypes);
@@ -3037,7 +3038,8 @@ bool FunctionType::isPure() const
 		m_kind == Kind::ABIEncodePacked ||
 		m_kind == Kind::ABIEncodeWithSelector ||
 		m_kind == Kind::ABIEncodeWithSignature ||
-		m_kind == Kind::ABIDecode;
+		m_kind == Kind::ABIDecode ||
+		m_kind == Kind::MetaType;
 }
 
 TypePointers FunctionType::parseElementaryTypeVector(strings const& _types)
@@ -3305,6 +3307,14 @@ string ModuleType::toString(bool) const
 	return string("module \"") + m_sourceUnit.annotation().path + string("\"");
 }
 
+shared_ptr<MagicType> MagicType::metaType(TypePointer _type)
+{
+	solAssert(_type && _type->category() == Type::Category::Contract, "Only contracts supported for now.");
+	auto t = make_shared<MagicType>(Kind::MetaType);
+	t->m_typeArgument = std::move(_type);
+	return t;
+}
+
 string MagicType::richIdentifier() const
 {
 	switch (m_kind)
@@ -3317,6 +3327,9 @@ string MagicType::richIdentifier() const
 		return "t_magic_transaction";
 	case Kind::ABI:
 		return "t_magic_abi";
+	case Kind::MetaType:
+		solAssert(m_typeArgument, "");
+		return "t_magic_meta_type_" + m_typeArgument->richIdentifier();
 	}
 	return "";
 }
@@ -3403,12 +3416,27 @@ MemberList::MemberMap MagicType::nativeMembers(ContractDefinition const*) const
 				StateMutability::Pure
 			)}
 		});
-	default:
-		solAssert(false, "Unknown kind of magic.");
+	case Kind::MetaType:
+	{
+		solAssert(
+			m_typeArgument && m_typeArgument->category() == Type::Category::Contract,
+			"Only contracts supported for now"
+		);
+		ContractDefinition const& contract = dynamic_cast<ContractType const&>(*m_typeArgument).contractDefinition();
+		if (contract.annotation().unimplementedFunctions.empty() && contract.constructorIsPublic())
+			return MemberList::MemberMap({
+				{"creationCode", std::make_shared<ArrayType>(DataLocation::Memory)},
+				{"runtimeCode", std::make_shared<ArrayType>(DataLocation::Memory)}
+			});
+		else
+			return {};
 	}
+	}
+	solAssert(false, "Unknown kind of magic.");
+	return {};
 }
 
-string MagicType::toString(bool) const
+string MagicType::toString(bool _short) const
 {
 	switch (m_kind)
 	{
@@ -3420,7 +3448,10 @@ string MagicType::toString(bool) const
 		return "tx";
 	case Kind::ABI:
 		return "abi";
-	default:
-		solAssert(false, "Unknown kind of magic.");
+	case Kind::MetaType:
+		solAssert(m_typeArgument, "");
+		return "type(" + m_typeArgument->toString(_short) + ")";
 	}
+	solAssert(false, "Unknown kind of magic.");
+	return {};
 }
diff --git a/libsolidity/ast/Types.h b/libsolidity/ast/Types.h
index bee00661..5427786a 100644
--- a/libsolidity/ast/Types.h
+++ b/libsolidity/ast/Types.h
@@ -989,6 +989,7 @@ public:
 		ABIEncodeWithSignature,
 		ABIDecode,
 		GasLeft, ///< gasleft()
+		MetaType ///< type(...)
 	};
 
 	Category category() const override { return Category::Function; }
@@ -1299,16 +1300,23 @@ private:
 };
 
 /**
- * Special type for magic variables (block, msg, tx), similar to a struct but without any reference
- * (it always references a global singleton by name).
+ * Special type for magic variables (block, msg, tx, type(...)), similar to a struct but without any reference.
  */
 class MagicType: public Type
 {
 public:
-	enum class Kind { Block, Message, Transaction, ABI };
+	enum class Kind {
+		Block, ///< "block"
+		Message, ///< "msg"
+		Transaction, ///< "tx"
+		ABI, ///< "abi"
+		MetaType ///< "type(...)"
+	};
 	Category category() const override { return Category::Magic; }
 
 	explicit MagicType(Kind _kind): m_kind(_kind) {}
+	/// Factory function for meta type
+	static std::shared_ptr<MagicType> metaType(TypePointer _type);
 
 	TypeResult binaryOperatorResult(Token, TypePointer const&) const override
 	{
@@ -1329,6 +1337,9 @@ public:
 
 private:
 	Kind m_kind;
+	/// Contract type used for contract metadata magic.
+	TypePointer m_typeArgument;
+
 };
 
 /**
diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp
index be2709ae..5c2fa6d0 100644
--- a/libsolidity/codegen/ExpressionCompiler.cpp
+++ b/libsolidity/codegen/ExpressionCompiler.cpp
@@ -1107,6 +1107,9 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 		case FunctionType::Kind::GasLeft:
 			m_context << Instruction::GAS;
 			break;
+		case FunctionType::Kind::MetaType:
+			// No code to generate.
+			break;
 		}
 	}
 	return false;
diff --git a/libsolidity/parsing/Parser.cpp b/libsolidity/parsing/Parser.cpp
index 8a6bc343..35476a76 100644
--- a/libsolidity/parsing/Parser.cpp
+++ b/libsolidity/parsing/Parser.cpp
@@ -1551,6 +1551,12 @@ ASTPointer<Expression> Parser::parsePrimaryExpression()
 		nodeFactory.markEndPosition();
 		expression = nodeFactory.createNode<Identifier>(getLiteralAndAdvance());
 		break;
+	case Token::Type:
+		// Inside expressions "type" is the name of a special, globally-available function.
+		nodeFactory.markEndPosition();
+		m_scanner->next();
+		expression = nodeFactory.createNode<Identifier>(make_shared<ASTString>("type"));
+		break;
 	case Token::LParen:
 	case Token::LBrack:
 	{