Check for recursive structs.

libsolidity/ast/Types.cpp

@@ -1769,8 +1769,10 @@ TypePointer StructType::interfaceType(bool _inLibrary) const
 {
 	if (_inLibrary && location() == DataLocation::Storage)
 		return shared_from_this();
-	else
+	else if (!recursive())
 		return copyForLocation(DataLocation::Memory, true);
+	else
+		return TypePointer();
 }
 
 TypePointer StructType::copyForLocation(DataLocation _location, bool _isPointer) const
@@ -1836,6 +1838,29 @@ set<string> StructType::membersMissingInMemory() const
 	return missing;
 }
 
+bool StructType::recursive() const
+{
+	set<StructDefinition const*> structsSeen;
+	function<bool(StructType const*)> check = [&](StructType const* t) -> bool
+	{
+		StructDefinition const* str = &t->structDefinition();
+		if (structsSeen.count(str))
+			return true;
+		structsSeen.insert(str);
+		for (ASTPointer<VariableDeclaration> const& variable: str->members())
+		{
+			Type const* memberType = variable->annotation().type.get();
+			while (dynamic_cast<ArrayType const*>(memberType))
+				memberType = dynamic_cast<ArrayType const*>(memberType)->baseType().get();
+			if (StructType const* innerStruct = dynamic_cast<StructType const*>(memberType))
+				if (check(innerStruct))
+					return true;
+		}
+		return false;
+	};
+	return check(this);
+}
+
 TypePointer EnumType::unaryOperatorResult(Token::Value _operator) const
 {
 	return _operator == Token::Delete ? make_shared<TupleType>() : TypePointer();

libsolidity/ast/Types.h

@@ -758,6 +758,10 @@ public:
 	/// @returns the set of all members that are removed in the memory version (typically mappings).
 	std::set<std::string> membersMissingInMemory() const;
 
+	/// @returns true if the same struct is used recursively in one of its members. Only
+	/// analyses the "memory" representation, i.e. mappings are ignored in all structs.
+	bool recursive() const;
+
 private:
 	StructDefinition const& m_struct;
 };