Merge pull request #2936 from ethereum/proper-address-overload-resolution

Fix overload resolution when conflict is with members of address

Changelog.md

@@ -5,6 +5,8 @@ Features:
 
 Bugfixes:
  * Parser: Fix source location of VariableDeclarationStatement.
+ * Type Checker: Properly support overwriting members inherited from ``address`` in a contract
+   (such as ``balance``, ``transfer``, etc.)
 
 ### 0.4.17 (2017-09-21)
 

libsolidity/ast/Types.cpp

@@ -1618,8 +1618,7 @@ string ContractType::canonicalName() const
 
 MemberList::MemberMap ContractType::nativeMembers(ContractDefinition const*) const
 {
-	// All address members and all interface functions
-	MemberList::MemberMap members(IntegerType(160, IntegerType::Modifier::Address).nativeMembers(nullptr));
+	MemberList::MemberMap members;
 	if (m_super)
 	{
 		// add the most derived of all functions which are visible in derived contracts
@@ -1661,9 +1660,45 @@ MemberList::MemberMap ContractType::nativeMembers(ContractDefinition const*) con
 				&it.second->declaration()
 			));
 	}
+	addNonConflictingAddressMembers(members);
 	return members;
 }
 
+void ContractType::addNonConflictingAddressMembers(MemberList::MemberMap& _members)
+{
+	MemberList::MemberMap addressMembers = IntegerType(160, IntegerType::Modifier::Address).nativeMembers(nullptr);
+	for (auto const& addressMember: addressMembers)
+	{
+		bool clash = false;
+		for (auto const& member: _members)
+		{
+			if (
+				member.name == addressMember.name &&
+				(
+					// Members with different types are not allowed
+					member.type->category() != addressMember.type->category() ||
+					// Members must overload functions without clash
+					(
+						member.type->category() == Type::Category::Function &&
+						dynamic_cast<FunctionType const&>(*member.type).hasEqualArgumentTypes(dynamic_cast<FunctionType const&>(*addressMember.type))
+					)
+				)
+			)
+			{
+				clash = true;
+				break;
+			}
+		}
+
+		if (!clash)
+			_members.push_back(MemberList::Member(
+				addressMember.name,
+				addressMember.type,
+				addressMember.declaration
+			));
+	}
+}
+
 shared_ptr<FunctionType const> const& ContractType::newExpressionType() const
 {
 	if (!m_constructorType)

libsolidity/ast/Types.h

@@ -716,6 +716,8 @@ public:
 	std::vector<std::tuple<VariableDeclaration const*, u256, unsigned>> stateVariables() const;
 
 private:
+	static void addNonConflictingAddressMembers(MemberList::MemberMap& _members);
+
 	ContractDefinition const& m_contract;
 	/// If true, it is the "super" type of the current contract, i.e. it contains only inherited
 	/// members.

test/libsolidity/SolidityEndToEndTest.cpp

@@ -10151,6 +10151,31 @@ BOOST_AUTO_TEST_CASE(constant_string)
 	ABI_CHECK(callContractFunction("h()"), encodeDyn(string("hello")));
 }
 
+BOOST_AUTO_TEST_CASE(address_overload_resolution)
+{
+	char const* sourceCode = R"(
+		contract C {
+			function balance() returns (uint) {
+				return 1;
+			}
+			function transfer(uint amount) returns (uint) {
+				return amount;
+			}
+		}
+		contract D {
+			function f() returns (uint) {
+				return (new C()).balance();
+			}
+			function g() returns (uint) {
+				return (new C()).transfer(5);
+			}
+		}
+	)";
+	compileAndRun(sourceCode, 0, "D");
+	BOOST_CHECK(callContractFunction("f()") == encodeArgs(u256(1)));
+	BOOST_CHECK(callContractFunction("g()") == encodeArgs(u256(5)));
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }

test/libsolidity/SolidityNameAndTypeResolution.cpp

@@ -6953,6 +6953,29 @@ BOOST_AUTO_TEST_CASE(warn_about_suicide)
 	CHECK_WARNING(text, "\"suicide\" has been deprecated in favour of \"selfdestruct\"");
 }
 
+BOOST_AUTO_TEST_CASE(address_overload_resolution)
+{
+	char const* text = R"(
+		contract C {
+			function balance() returns (uint) {
+				this.balance; // to avoid pureness warning
+				return 1;
+			}
+			function transfer(uint amount) {
+				address(this).transfer(amount); // to avoid pureness warning
+			}
+		}
+		contract D {
+			function f() {
+				var x = (new C()).balance();
+				x;
+				(new C()).transfer(5);
+			}
+		}
+	)";
+	CHECK_SUCCESS(text);
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }