Merge pull request #2688 from chriseth/toBytesConversion

Allow explicit conversions bytes <-> string.

AST.cpp

@@ -844,9 +844,15 @@ void FunctionCall::checkTypeRequirements(TypePointers const*)
 			BOOST_THROW_EXCEPTION(createTypeError("Exactly one argument expected for explicit type conversion."));
 		if (!isPositionalCall)
 			BOOST_THROW_EXCEPTION(createTypeError("Type conversion cannot allow named arguments."));
-		if (!m_arguments.front()->getType()->isExplicitlyConvertibleTo(*type.getActualType()))
-			BOOST_THROW_EXCEPTION(createTypeError("Explicit type conversion not allowed."));
 		m_type = type.getActualType();
+		auto argType = m_arguments.front()->getType();
+		if (auto argRefType = dynamic_cast<ReferenceType const*>(argType.get()))
+			// do not change the data location when converting
+			// (data location cannot yet be specified for type conversions)
+			m_type = ReferenceType::copyForLocationIfReference(argRefType->location(), m_type);
+		if (!argType->isExplicitlyConvertibleTo(*m_type))
+			BOOST_THROW_EXCEPTION(createTypeError("Explicit type conversion not allowed."));
+
 		return;
 	}
 

CompilerUtils.cpp

@@ -404,7 +404,7 @@ void CompilerUtils::convertType(Type const& _typeOnStack, Type const& _targetTyp
 		case DataLocation::Storage:
 			// Other cases are done explicitly in LValue::storeValue, and only possible by assignment.
 			solAssert(
-				targetType.isPointer() &&
+				(targetType.isPointer() || (typeOnStack.isByteArray() && targetType.isByteArray())) &&
 				typeOnStack.location() == DataLocation::Storage,
 				"Invalid conversion to storage type."
 			);
@@ -469,6 +469,13 @@ void CompilerUtils::convertType(Type const& _typeOnStack, Type const& _targetTyp
 			}
 			break;
 		}
+		case DataLocation::CallData:
+			solAssert(
+					targetType.isByteArray() &&
+					typeOnStack.isByteArray() &&
+					typeOnStack.location() == DataLocation::CallData,
+				"Invalid conversion to calldata type.");
+			break;
 		default:
 			solAssert(
 				false,

Types.cpp

@@ -789,6 +789,21 @@ bool ArrayType::isImplicitlyConvertibleTo(const Type& _convertTo) const
 	}
 }
 
+bool ArrayType::isExplicitlyConvertibleTo(const Type& _convertTo) const
+{
+	if (isImplicitlyConvertibleTo(_convertTo))
+		return true;
+	// allow conversion bytes <-> string
+	if (_convertTo.getCategory() != getCategory())
+		return false;
+	auto& convertTo = dynamic_cast<ArrayType const&>(_convertTo);
+	if (convertTo.location() != location())
+		return false;
+	if (!isByteArray() || !convertTo.isByteArray())
+		return false;
+	return true;
+}
+
 bool ArrayType::operator==(Type const& _other) const
 {
 	if (_other.getCategory() != getCategory())

Types.h

@@ -477,6 +477,7 @@ public:
 	{}
 
 	virtual bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
+	virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
 	virtual bool operator==(const Type& _other) const override;
 	virtual unsigned getCalldataEncodedSize(bool _padded) const override;
 	virtual bool isDynamicallySized() const override { return m_hasDynamicLength; }