整数变量和数组变量之间的奇怪区别

a = 1
def bla x
 x = x + 1
end

bla a # =>2 when I use bla to add 1, it return 2

a # => 1 but it get back to the original value

a = [1] 
a = 1
def bla x
 x = x + 1
end

bla a # =>2 whe