Check for recursive structs.

3 files changed, 33 insertions, 4 deletions

diff --git a/libsolidity/analysis/TypeChecker.cpp b/libsolidity/analysis/TypeChecker.cpp
index 26529c22..fe4207a3 100644
--- a/libsolidity/analysis/TypeChecker.cpp
+++ b/libsolidity/analysis/TypeChecker.cpp
@@ -546,7 +546,7 @@ bool TypeChecker::visit(FunctionDefinition const& _function)
 		if (!type(*var)->canLiveOutsideStorage())
 			m_errorReporter.typeError(var->location(), "Type is required to live outside storage.");
 		if (_function.visibility() >= FunctionDefinition::Visibility::Public && !(type(*var)->interfaceType(isLibraryFunction)))
-			m_errorReporter.fatalTypeError(var->location(), "Internal type is not allowed for public or external functions.");
+			m_errorReporter.fatalTypeError(var->location(), "Internal or recursive type is not allowed for public or external functions.");
 
 		var->accept(*this);
 	}
@@ -641,7 +641,7 @@ bool TypeChecker::visit(VariableDeclaration const& _variable)
 		_variable.visibility() >= VariableDeclaration::Visibility::Public &&
 		!FunctionType(_variable).interfaceFunctionType()
 	)
-		m_errorReporter.typeError(_variable.location(), "Internal type is not allowed for public state variables.");
+		m_errorReporter.typeError(_variable.location(), "Internal or recursive type is not allowed for public state variables.");
 
 	if (varType->category() == Type::Category::Array)
 		if (auto arrayType = dynamic_cast<ArrayType const*>(varType.get()))
@@ -728,7 +728,7 @@ bool TypeChecker::visit(EventDefinition const& _eventDef)
 		if (!type(*var)->canLiveOutsideStorage())
 			m_errorReporter.typeError(var->location(), "Type is required to live outside storage.");
 		if (!type(*var)->interfaceType(false))
-			m_errorReporter.typeError(var->location(), "Internal type is not allowed as event parameter type.");
+			m_errorReporter.typeError(var->location(), "Internal or recursive type is not allowed as event parameter type.");
 	}
 	if (_eventDef.isAnonymous() && numIndexed > 4)
 		m_errorReporter.typeError(_eventDef.location(), "More than 4 indexed arguments for anonymous event.");
diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index 3a93b74e..44316403 100644
--- a/libsolidity/ast/Types.cpp
+++ b/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();
diff --git a/libsolidity/ast/Types.h b/libsolidity/ast/Types.h
index d4d6da69..e6d3a7b1 100644
--- a/libsolidity/ast/Types.h
+++ b/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;
 };