diff --git a/src/Expr.cc b/src/Expr.cc
index e652a3d09a..4aa6bd0f30 100644
--- a/src/Expr.cc
+++ b/src/Expr.cc
@@ -1984,7 +1984,7 @@ RefExpr::RefExpr(IntrusivePtr<Expr> arg_op)
 	if ( IsError() )
 		return;
 
-	if ( ! ::is_assignable(op->GetType().get()) )
+	if ( ! ::is_assignable(op->GetType()->Tag()) )
 		ExprError("illegal assignment target");
 	else
 		SetType(op->GetType());
diff --git a/src/Type.cc b/src/Type.cc
index 158c8b0ccf..7260c4194c 100644
--- a/src/Type.cc
+++ b/src/Type.cc
@@ -1644,9 +1644,9 @@ BroType* flatten_type(BroType* t)
 	return (BroType*) flatten_type((const BroType*) t);
 	}
 
-bool is_assignable(BroType* t)
+bool is_assignable(TypeTag t)
 	{
-	switch ( t->Tag() ) {
+	switch ( t ) {
 	case TYPE_BOOL:
 	case TYPE_INT:
 	case TYPE_COUNT:
diff --git a/src/Type.h b/src/Type.h
index 92bd2c5ef2..8e30e705cb 100644
--- a/src/Type.h
+++ b/src/Type.h
@@ -867,7 +867,9 @@ inline bool is_atomic_type(const IntrusivePtr<BroType>& t)
 	{ return is_atomic_type(*t); }
 
 // True if the given type tag corresponds to type that can be assigned to.
-extern bool is_assignable(BroType* t);
+extern bool is_assignable(TypeTag t);
+inline bool is_assignable(BroType* t)
+	{ return ::is_assignable(t->Tag()); }
 
 // True if the given type tag corresponds to an integral type.
 inline bool IsIntegral(TypeTag t) { return (t == TYPE_INT || t == TYPE_COUNT || t == TYPE_COUNTER); }