Type conversion specialities for storage references.

libsolidity/CompilerUtils.cpp

@@ -274,10 +274,13 @@ void CompilerUtils::encodeToMemory(
 		else
 		{
 			copyToStackTop(argSize - stackPos + dynPointers + 2, _givenTypes[i]->getSizeOnStack());
-			if (targetType->isValueType())
-				convertType(*_givenTypes[i], *targetType, true);
 			solAssert(!!targetType, "Externalable type expected.");
-			storeInMemoryDynamic(*targetType, _padToWordBoundaries);
+			TypePointer type = targetType;
+			if (_givenTypes[i]->isInStorage())
+				type = _givenTypes[i]; // delay conversion
+			else
+				convertType(*_givenTypes[i], *targetType, true);
+			storeInMemoryDynamic(*type, _padToWordBoundaries);
 		}
 		stackPos += _givenTypes[i]->getSizeOnStack();
 	}

libsolidity/ExpressionCompiler.cpp

@@ -146,10 +146,13 @@ bool ExpressionCompiler::visit(Assignment const& _assignment)
 {
 	CompilerContext::LocationSetter locationSetter(m_context, _assignment);
 	_assignment.getRightHandSide().accept(*this);
-	if (_assignment.getType()->isValueType())
+	TypePointer type = _assignment.getRightHandSide().getType();
-		utils().convertType(*_assignment.getRightHandSide().getType(), *_assignment.getType());
+	if (!_assignment.getType()->isInStorage())
-	// We need this conversion mostly in the case of compound assignments. For non-value types
+	{
-	// the conversion is done in LValue::storeValue.
+		utils().convertType(*type, *_assignment.getType());
+		type = _assignment.getType();
+	}
+
 	_assignment.getLeftHandSide().accept(*this);
 	solAssert(!!m_currentLValue, "LValue not retrieved.");
 
@@ -175,7 +178,7 @@ bool ExpressionCompiler::visit(Assignment const& _assignment)
 				m_context << eth::swapInstruction(itemSize + lvalueSize) << eth::Instruction::POP;
 		}
 	}
-	m_currentLValue->storeValue(*_assignment.getRightHandSide().getType(), _assignment.getLocation());
+	m_currentLValue->storeValue(*type, _assignment.getLocation());
 	m_currentLValue.reset();
 	return false;
 }
@@ -1119,14 +1122,10 @@ void ExpressionCompiler::appendExternalFunctionCall(
 
 void ExpressionCompiler::appendExpressionCopyToMemory(Type const& _expectedType, Expression const& _expression)
 {
+	solAssert(_expectedType.isValueType(), "Not implemented for non-value types.");
 	_expression.accept(*this);
-	if (_expectedType.isValueType())
+	utils().convertType(*_expression.getType(), _expectedType, true);
-	{
+	utils().storeInMemoryDynamic(_expectedType);
-		utils().convertType(*_expression.getType(), _expectedType, true);
-		utils().storeInMemoryDynamic(_expectedType);
-	}
-	else
-		utils().storeInMemoryDynamic(*_expression.getType()->mobileType());
 }
 
 void ExpressionCompiler::setLValueFromDeclaration(Declaration const& _declaration, Expression const& _expression)

libsolidity/Types.h

@@ -202,6 +202,8 @@ public:
 	/// This returns the corresponding integer type for IntegerConstantTypes and the pointer type
 	/// for storage reference types.
 	virtual TypePointer mobileType() const { return shared_from_this(); }
+	/// @returns true if this type is a storage pointer or reference.
+	virtual bool isInStorage() const { return false; }
 
 	/// Returns the list of all members of this type. Default implementation: no members.
 	virtual MemberList const& getMembers() const { return EmptyMemberList; }
@@ -374,6 +376,7 @@ public:
 	virtual TypePointer copyForLocation(Location _location, bool _isPointer) const = 0;
 
 	virtual TypePointer mobileType() const override { return copyForLocation(m_location, true); }
+	virtual bool isInStorage() const override { return m_location == Location::Storage; }
 
 	/// Storage references can be pointers or bound references. In general, local variables are of
 	/// pointer type, state variables are bound references. Assignments to pointers or deleting

test/libsolidity/SolidityEndToEndTest.cpp

@@ -4243,9 +4243,9 @@ BOOST_AUTO_TEST_CASE(return_string)
 			function get1() returns (string r) {
 				return s;
 			}
-//			function get2() returns (string r) {
+			function get2() returns (string r) {
-//				r = s;
+				r = s;
-//			}
+			}
 		}
 	)";
 	compileAndRun(sourceCode, 0, "Main");
@@ -4253,8 +4253,8 @@ BOOST_AUTO_TEST_CASE(return_string)
 	bytes args = encodeArgs(u256(0x20), u256(s.length()), s);
 	BOOST_REQUIRE(callContractFunction("set(string)", asString(args)) == encodeArgs());
 	BOOST_CHECK(callContractFunction("get1()") == args);
-//	BOOST_CHECK(callContractFunction("get2()") == args);
+	BOOST_CHECK(callContractFunction("get2()") == args);
-//	BOOST_CHECK(callContractFunction("s()") == args);
+	BOOST_CHECK(callContractFunction("s()") == args);
 }
 
 BOOST_AUTO_TEST_SUITE_END()