steep check: &nil is treated as block

[palkan]

Example:

# a.rb
class A
  def foo(val)
    val
  end
end

class B < A
  def foo(val, &block)
    block.call super(val, &nil)
  end
end

# a.rbs
class A
  def foo: (String) -> String
end

class B < A
  def foo: (String) { (String) -> String} -> String
end

Running Steep check:

$ steep check

a.rb:9:15: UnexpectedBlockGiven: method_type=(::String) -> ::String (super(val, &nil))

Removing &nil works with steep check but breaks when using rbs/test/setup (with UnexpectedBlockError: unexpected block is given for ...).