diff --git a/libsolidity/analysis/ReferencesResolver.cpp b/libsolidity/analysis/ReferencesResolver.cpp
index 30aa3d498..6217c5d15 100644
--- a/libsolidity/analysis/ReferencesResolver.cpp
+++ b/libsolidity/analysis/ReferencesResolver.cpp
@@ -231,8 +231,6 @@ void ReferencesResolver::endVisit(Mapping const& _typeName)
 void ReferencesResolver::endVisit(ArrayTypeName const& _typeName)
 {
 	TypePointer baseType = _typeName.baseType().annotation().type;
-	auto arrayType = dynamic_cast<ArrayType const*>(baseType.get());
-	bool isFixedSizeArray = (arrayType && arrayType->isByteArray()) || !baseType->isDynamicallySized();
 	if (!baseType)
 	{
 		solAssert(!m_errorReporter.errors().empty(), "");
@@ -243,12 +241,14 @@ void ReferencesResolver::endVisit(ArrayTypeName const& _typeName)
 	if (Expression const* length = _typeName.length())
 	{
 		TypePointer lengthTypeGeneric = length->annotation().type;
+		auto arrayType = dynamic_cast<ArrayType const*>(baseType.get());
+		bool isByteOrFixedSizeArray = (arrayType && arrayType->isByteArray()) || !baseType->isDynamicallySized();
 		if (!lengthTypeGeneric)
 			lengthTypeGeneric = ConstantEvaluator(m_errorReporter).evaluate(*length);
 		RationalNumberType const* lengthType = dynamic_cast<RationalNumberType const*>(lengthTypeGeneric.get());
 		if (!lengthType || !lengthType->mobileType())
 			fatalTypeError(length->location(), "Invalid array length, expected integer literal or constant expression.");
-		else if (lengthType->isZero() && isFixedSizeArray)
+		else if (lengthType->isZero() && isByteOrFixedSizeArray)
 			fatalTypeError(length->location(), "Array with zero length specified.");
 		else if (lengthType->isFractional())
 			fatalTypeError(length->location(), "Array with fractional length specified.");