why?.rb

impress[prod]>> inner = Array.new
=> []
impress[prod]>> inner.push {"a" => "b"}
SyntaxError: compile error                                     <--- why???
(irb):3: syntax error, unexpected tASSOC, expecting '}'
inner.push {"a" => "b"}
                  ^
        from (irb):3
impress[prod]>> inner.push {{"a" => "b"}}
=> []
impress[prod]>> inner
=> []
impress[prod]>> ii = Hash.new
=> {}
impress[prod]>> ii = {"a" => "b"}
=> {"a"=>"b"}
impress[prod]>> inner.push ii                                  <--- same thing?
=> [{"a"=>"b"}]