Bugfix for functions override

- Functions with byte array type parameters can now be safely
  overriden. Parameter location is now set at the right place.

- Also made a test for the fix

libsolidity/AST.cpp

@@ -274,15 +274,6 @@ TypePointer FunctionDefinition::getType(ContractDefinition const*) const
 
 void FunctionDefinition::checkTypeRequirements()
 {
-	// change all byte arrays parameters to point to calldata
-	if (getVisibility() == Visibility::External)
-		for (ASTPointer<VariableDeclaration> const& var: getParameters())
-		{
-			auto const& type = var->getType();
-			solAssert(!!type, "");
-			if (auto const* byteArrayType = dynamic_cast<ByteArrayType const*>(type.get()))
-				var->setType(byteArrayType->copyForLocation(ByteArrayType::Location::CallData));
-		}
 	for (ASTPointer<VariableDeclaration> const& var: getParameters() + getReturnParameters())
 		if (!var->getType()->canLiveOutsideStorage())
 			BOOST_THROW_EXCEPTION(var->createTypeError("Type is required to live outside storage."));
@@ -299,16 +290,14 @@ string FunctionDefinition::getCanonicalSignature() const
 
 bool VariableDeclaration::isLValue() const
 {
-	if (auto const* function = dynamic_cast<FunctionDefinition const*>(getScope()))
-		if (function->getVisibility() == Declaration::Visibility::External && isFunctionParameter())
-			return false;
-	return true;
+	// External function parameters are Read-Only
+	return !isExternalFunctionParameter();
 }
 
-bool VariableDeclaration::isFunctionParameter() const
+bool VariableDeclaration::isExternalFunctionParameter() const
 {
 	auto const* function = dynamic_cast<FunctionDefinition const*>(getScope());
-	if (!function)
+	if (!function || function->getVisibility() != Declaration::Visibility::External)
 		return false;
 	for (auto const& variable: function->getParameters())
 		if (variable.get() == this)

libsolidity/AST.h

@@ -448,7 +448,7 @@ public:
 
 	virtual bool isLValue() const override;
 	bool isLocalVariable() const { return !!dynamic_cast<FunctionDefinition const*>(getScope()); }
-	bool isFunctionParameter() const;
+	bool isExternalFunctionParameter() const;
 	bool isStateVariable() const { return m_isStateVariable; }
 	bool isIndexed() const { return m_isIndexed; }
 

libsolidity/NameAndTypeResolver.cpp

@@ -333,7 +333,13 @@ void ReferencesResolver::endVisit(VariableDeclaration& _variable)
 	// or mapping
 	if (_variable.getTypeName())
 	{
-		_variable.setType(_variable.getTypeName()->toType());
+		TypePointer type = _variable.getTypeName()->toType();
+		// All byte array parameter types should point to call data
+		if (_variable.isExternalFunctionParameter())
+			if (auto const* byteArrayType = dynamic_cast<ByteArrayType const*>(type.get()))
+				type = byteArrayType->copyForLocation(ByteArrayType::Location::CallData);
+		_variable.setType(type);
+
 		if (!_variable.getType())
 			BOOST_THROW_EXCEPTION(_variable.getTypeName()->createTypeError("Invalid type name"));
 	}

test/SolidityNameAndTypeResolution.cpp

@@ -1163,6 +1163,19 @@ BOOST_AUTO_TEST_CASE(external_argument_delete)
 	BOOST_CHECK_THROW(parseTextAndResolveNames(sourceCode), TypeError);
 }
 
+BOOST_AUTO_TEST_CASE(test_for_bug_override_function_with_bytearray_type)
+{
+	char const* sourceCode = R"(
+		contract Vehicle {
+			function f(bytes _a) external returns (uint256 r) {r = 1;}
+		}
+		contract Bike is Vehicle {
+			function f(bytes _a) external returns (uint256 r) {r = 42;}
+		}
+		)";
+	BOOST_CHECK_NO_THROW(parseTextAndResolveNamesWithChecks(sourceCode));
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }