4 files changed, 35 insertions, 0 deletions
diff --git a/libsolidity/analysis/ReferencesResolver.cpp b/libsolidity/analysis/ReferencesResolver.cpp
index a7b9e8b8..a0768a34 100644
--- a/libsolidity/analysis/ReferencesResolver.cpp
+++ b/libsolidity/analysis/ReferencesResolver.cpp
@@ -83,6 +83,31 @@ void ReferencesResolver::endVisit(UserDefinedTypeName const& _typeName)
 		fatalTypeError(_typeName.location(), "Name has to refer to a struct, enum or contract.");
 }
 
+void ReferencesResolver::endVisit(FunctionTypeName const& _typeName)
+{
+	switch (_typeName.visibility())
+	{
+	case VariableDeclaration::Visibility::Default:
+	case VariableDeclaration::Visibility::Internal:
+	case VariableDeclaration::Visibility::External:
+		break;
+	default:
+		typeError(_typeName.location(), "Invalid visibility, can only be \"external\" or \"internal\".");
+	}
+
+	if (_typeName.isPayable() && _typeName.visibility() != VariableDeclaration::Visibility::External)
+		fatalTypeError(_typeName.location(), "Only external function types can be payable.");
+	if (_typeName.visibility() == VariableDeclaration::Visibility::External)
+		for (auto const& t: _typeName.parameterTypes() + _typeName.returnParameterTypes())
+		{
+			solAssert(t->annotation().type, "Type not set for parameter.");
+			if (!t->annotation().type->canBeUsedExternally(false))
+				fatalTypeError(t->location(), "Internal type cannot be used for external function type.");
+		}
+
+	_typeName.annotation().type = make_shared<FunctionType>(_typeName);
+}
+
 void ReferencesResolver::endVisit(Mapping const& _typeName)
 {
 	TypePointer keyType = _typeName.keyType().annotation().type;
diff --git a/libsolidity/analysis/ReferencesResolver.h b/libsolidity/analysis/ReferencesResolver.h
index 1986b2bb..bfaef2e1 100644
--- a/libsolidity/analysis/ReferencesResolver.h
+++ b/libsolidity/analysis/ReferencesResolver.h
@@ -62,6 +62,7 @@ private:
 	virtual bool visit(Identifier const& _identifier) override;
 	virtual bool visit(ElementaryTypeName const& _typeName) override;
 	virtual void endVisit(UserDefinedTypeName const& _typeName) override;
+	virtual void endVisit(FunctionTypeName const& _typeName) override;
 	virtual void endVisit(Mapping const& _typeName) override;
 	virtual void endVisit(ArrayTypeName const& _typeName) override;
 	virtual bool visit(InlineAssembly const& _inlineAssembly) override;
diff --git a/libsolidity/analysis/TypeChecker.cpp b/libsolidity/analysis/TypeChecker.cpp
index f934b2c8..8b6d45e2 100644
--- a/libsolidity/analysis/TypeChecker.cpp
+++ b/libsolidity/analysis/TypeChecker.cpp
@@ -574,6 +574,14 @@ bool TypeChecker::visit(EventDefinition const& _eventDef)
 	return false;
 }
 
+void TypeChecker::endVisit(FunctionTypeName const& _funType)
+{
+	FunctionType const& fun = dynamic_cast<FunctionType const&>(*_funType.annotation().type);
+	if (fun.location() == FunctionType::Location::External)
+		if (!fun.canBeUsedExternally(false))
+			typeError(_funType.location(), "External function type uses internal types.");
+}
+
 bool TypeChecker::visit(InlineAssembly const& _inlineAssembly)
 {
 	// Inline assembly does not have its own type-checking phase, so we just run the
diff --git a/libsolidity/analysis/TypeChecker.h b/libsolidity/analysis/TypeChecker.h
index be1e02be..5874bb50 100644
--- a/libsolidity/analysis/TypeChecker.h
+++ b/libsolidity/analysis/TypeChecker.h
@@ -87,6 +87,7 @@ private:
 	/// case this is a base constructor call.
 	void visitManually(ModifierInvocation const& _modifier, std::vector<ContractDefinition const*> const& _bases);
 	virtual bool visit(EventDefinition const& _eventDef) override;
+	virtual void endVisit(FunctionTypeName const& _funType) override;
 	virtual bool visit(InlineAssembly const& _inlineAssembly) override;
 	virtual bool visit(IfStatement const& _ifStatement) override;
 	virtual bool visit(WhileStatement const& _whileStatement) override;