Implicit conversion from derived to base.

libsolidity/Types.cpp

@@ -431,12 +431,19 @@ bool ContractType::isImplicitlyConvertibleTo(Type const& _convertTo) const
 		return true;
 	if (_convertTo.getCategory() == Category::INTEGER)
 		return dynamic_cast<IntegerType const&>(_convertTo).isAddress();
+	if (_convertTo.getCategory() == Category::CONTRACT)
+	{
+		auto const& bases = getContractDefinition().getLinearizedBaseContracts();
+		return find(bases.begin(), bases.end(),
+					&dynamic_cast<ContractType const&>(_convertTo).getContractDefinition()) != bases.end();
+	}
 	return false;
 }
 
 bool ContractType::isExplicitlyConvertibleTo(Type const& _convertTo) const
 {
-	return isImplicitlyConvertibleTo(_convertTo) || _convertTo.getCategory() == Category::INTEGER;
+	return isImplicitlyConvertibleTo(_convertTo) || _convertTo.getCategory() == Category::INTEGER ||
+			_convertTo.getCategory() == Category::CONTRACT;
 }
 
 TypePointer ContractType::unaryOperatorResult(Token::Value _operator) const

test/SolidityNameAndTypeResolution.cpp

@@ -469,6 +469,27 @@ BOOST_AUTO_TEST_CASE(base_constructor_arguments_override)
 	BOOST_CHECK_THROW(parseTextAndResolveNames(text), TypeError);
 }
 
+BOOST_AUTO_TEST_CASE(implicit_derived_to_base_conversion)
+{
+	char const* text = R"(
+		contract A { }
+		contract B is A {
+			function f() { A a = B(1); }
+		}
+	)";
+	BOOST_CHECK_NO_THROW(parseTextAndResolveNames(text));
+}
+BOOST_AUTO_TEST_CASE(implicit_base_to_derived_conversion)
+{
+	char const* text = R"(
+		contract A { }
+		contract B is A {
+			function f() { B b = A(1); }
+		}
+	)";
+	BOOST_CHECK_THROW(parseTextAndResolveNames(text), TypeError);
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }