class RuboCop::Cop::Lint::NestedMethodDefinition

end
end
end
def bar
class << self
def foo
# good
@example
end
end
end
def bar
self.class.module_exec do
def foo
end
end
end
def bar
self.class.class_eval do
def foo
# good
@example
end
bar.call
bar = -> { puts ‘hello’ }
def foo
# good
@example
end
end
def bar
def foo
# will be redefined every time ‘foo` is invoked.
# as the outer `foo` method. Furthermore, the `bar` method
# `bar` definition actually produces methods in the same scope
# bad
@example
This cop checks for nested method definitions.

def on_def(node) 

def on_def(node)
  subject, = *node
  return if node.defs_type? && subject.lvar_type?
  def_ancestor = node.each_ancestor(:def, :defs).first
  return unless def_ancestor
  within_scoping_def =
    node.each_ancestor(:block, :sclass).any? do |ancestor|
      scoping_method_call?(ancestor)
    end
  add_offense(node) if def_ancestor && !within_scoping_def
end

def scoping_method_call?(child) 

def scoping_method_call?(child)
  child.sclass_type? || eval_call?(child) || exec_call?(child) ||
    class_or_module_or_struct_new_call?(child)
end