JSON.generate throw error for marshal.dump object data

[gotar]

json (1.8.1) ruby 2.1.0p0 (2013-12-25 revision 44422) [x86_64-darwin12.0]

2.1.0 :002 > JSON.generate(Marshal.dump(Time.now))
Encoding::UndefinedConversionError: "\x88" from ASCII-8BIT to UTF-8
    from /Users/gotar/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/json/common.rb:223:in `encode'
    from /Users/gotar/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/json/common.rb:223:in `generate'
    from /Users/gotar/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/json/common.rb:223:in `generate'
    from (irb):2
    from /Users/gotar/.rvm/rubies/ruby-2.1.0/bin/irb:11:in `<main>'

# The same

Marshal.dump(Time.now).to_json
Encoding::UndefinedConversionError: "\x88" from ASCII-8BIT to UTF-8
    from (irb):3:in `encode'
    from (irb):3:in `to_json'
    from (irb):3
    from /Users/gotar/.rvm/rubies/ruby-2.1.0/bin/irb:11:in `<main>'

But have those problems in different ruby versions too

[sharp]

same error

[ChrisCPO]

@sharp @gotar Did you find an an answer to this. I'm having an issue with this on rails 5.1 and ruby 5.5

[16] pry(main)> Marshal.dump(User.first).to_json
Encoding::UndefinedConversionError: "\x80" from ASCII-8BIT to UTF-8