class Steep::TypeInference::Context::TypeVariableContext

def self.empty
  new([])
end

def [](name)
  table.fetch(name).upper_bound
end

def initialize(type_params, parent_context: nil)
  @type_params = type_params
  @table = {}
  table.merge!(parent_context.table) if parent_context
  type_params.each do |param|
    table[param.name] = param
  end
end

def upper_bounds
  @upper_bounds ||= table.each_value.with_object({}) do |type_param, bounds| #$ Hash[Symbol, AST::Types::t]
    if type_param.upper_bound
      bounds[type_param.name] = type_param.upper_bound
    end
  end
end