class RBS::Environment::MultiEntry

def compatible_params?(ps1, ps2)
  if ps1.size == ps2.size
    ps1 == AST::TypeParam.rename(ps2, new_names: ps1.map(&:name))
  end
end

def initialize(name:)
  @name = name
  @decls = []
end

def insert(decl:, outer:)
  decls << D.new(decl: decl, outer: outer)
  @primary = nil
end

def primary
  raise "Not implemented"
end

def type_params
  primary.decl.type_params
end

def validate_type_params
  unless decls.empty?
    hd_decl, *tl_decls = decls
    raise unless hd_decl
    hd_params = hd_decl.decl.type_params
    tl_decls.each do |tl_decl|
      tl_params = tl_decl.decl.type_params
      unless compatible_params?(hd_params, tl_params)
        raise GenericParameterMismatchError.new(name: name, decl: _ = tl_decl.decl)
      end
    end
  end
end