codeql/ruby/ql/test/library-tests/variables/scopes.rb

def a ; "x" end
1.times do | x |
   puts a # not a local variable
   a = 3
   puts a # local variable
end
a = 6
puts a
1.times do | x |
   puts a # local variable from top-level
   a += 3
   puts a # local variable from top-level
   a, b, (c, d) = [4, 5, [6, 7]]
   puts a # local variable from top-level
   puts b # new local variable
   puts c # new local variable
   puts d # new local variable
end

# new global variable
$global = 42

# use of a pre-defined global variable
script = $0

class A; end
x = A
module x::B
  x = 1
end
class << x
  x = 2
end
class x::C < x
  x = 3
end
def x.foo
  x = 4
end

module M
 var =  1
 foo = <<-EOF
  #{var}
  #{fun}
  #{var2 = 10}
  #{var2}
 EOF
end