diff --git a/libsolidity/AST.cpp b/libsolidity/AST.cpp
index 7fe3a9825..a111a6f88 100644
--- a/libsolidity/AST.cpp
+++ b/libsolidity/AST.cpp
@@ -338,7 +338,14 @@ void FunctionDefinition::checkTypeRequirements()
 		if (!var->getType()->canLiveOutsideStorage())
 			BOOST_THROW_EXCEPTION(var->createTypeError("Type is required to live outside storage."));
 		if (getVisibility() >= Visibility::Public && !(var->getType()->externalType()))
-			BOOST_THROW_EXCEPTION(var->createTypeError("Internal type is not allowed for function with external visibility"));
+		{
+			// todo delete when arrays as parameter type in internal functions will be implemented
+			ArrayType const* type = dynamic_cast<ArrayType const*>(var->getType().get());
+			if (getVisibility() == Visibility::Public && type)
+				BOOST_THROW_EXCEPTION(var->createTypeError("Array type is not allowed as parameter for internal functions."));
+			else
+				BOOST_THROW_EXCEPTION(var->createTypeError("Internal type is not allowed for function with external visibility."));
+		}
 	}
 	for (ASTPointer<ModifierInvocation> const& modifier: m_functionModifiers)
 		modifier->checkTypeRequirements(isConstructor() ?
@@ -379,6 +386,14 @@ void VariableDeclaration::checkTypeRequirements()
 		m_value->expectType(*m_type);
 		if (m_isStateVariable && !m_type->externalType() && getVisibility() >= Visibility::Public)
 			BOOST_THROW_EXCEPTION(createTypeError("Internal type is not allowed for state variables."));
+
+		auto sharedToExternalTypes = FunctionType(*this).externalType(); // do not distroy the shared pointer.
+		auto externalFunctionTypes = dynamic_cast<FunctionType const*>(sharedToExternalTypes.get());
+		TypePointers retParamTypes = externalFunctionTypes->getReturnParameterTypes();
+		TypePointers parameterTypes = externalFunctionTypes->getParameterTypes();
+		for (auto parameter: parameterTypes + retParamTypes)
+		if (!parameter && !(parameter->externalType()))
+			BOOST_THROW_EXCEPTION(createTypeError("Internal type is not allowed for state variables."));
 	} else
 	{
 		// no type declared and no previous assignment, infer the type
diff --git a/test/SolidityNameAndTypeResolution.cpp b/test/SolidityNameAndTypeResolution.cpp
index ddcf36140..531f3bc13 100644
--- a/test/SolidityNameAndTypeResolution.cpp
+++ b/test/SolidityNameAndTypeResolution.cpp
@@ -460,7 +460,7 @@ BOOST_AUTO_TEST_CASE(function_external_types)
 			uint a;
 		}
 		contract Test {
-			function boo(uint arg2, bool arg3, bytes8 arg4, bool[2] pairs, uint[] dynamic, C carg) external returns (uint ret) {
+			function boo(uint arg2, bool arg3, bytes8 arg4, bool[2] pairs, uint[] dynamic, C carg, address[] addresses) external returns (uint ret) {
 			   ret = 5;
 			}
 		})";
@@ -471,7 +471,7 @@ BOOST_AUTO_TEST_CASE(function_external_types)
 			auto functions = contract->getDefinedFunctions();
 			if (functions.empty())
 				continue;
-			BOOST_CHECK_EQUAL("boo(uint256,bool,bytes8,bool[2],uint256[],address)", functions[0]->externalSignature());
+			BOOST_CHECK_EQUAL("boo(uint256,bool,bytes8,bool[2],uint256[],address,address[])", functions[0]->externalSignature());
 		}
 }
 
@@ -503,6 +503,16 @@ BOOST_AUTO_TEST_CASE(function_external_call_not_allowed_conversion)
 	BOOST_CHECK_THROW(parseTextAndResolveNames(text), TypeError);
 }
 
+// todo delete when implemented
+BOOST_AUTO_TEST_CASE(arrays_in_internal_functions)
+{
+	char const* text = R"(
+		contract Test {
+			function foo(address[] addresses) {}
+	})";
+	BOOST_CHECK_THROW(parseTextAndResolveNames(text), TypeError);
+}
+
 BOOST_AUTO_TEST_CASE(function_internal_allowed_conversion)
 {
 	char const* text = R"(