lib/grumlin/typing.rb in grumlin-0.19.2 vs lib/grumlin/typing.rb in grumlin-0.19.3

@@ -19,10 +19,10 @@
       "g:TraversalMetrics" => ->(value) { cast_map(value[:@value]) },
       "g:Metrics" => ->(value) { cast_map(value[:@value]) },
       "g:T" => ->(value) { Grumlin::Expressions::T.public_send(value) }
     }.freeze
 
-    CASTABLE_TYPES = [Hash, String, Integer, TrueClass, FalseClass].freeze
+    CASTABLE_TYPES = [Hash, String, Integer, TrueClass, FalseClass, NilClass].freeze
 
     class << self
       def cast(value)
         verify_type!(value)