Failing Test: missing I18n::Backend::Simple::Dispatcher

I'm having trouble getting all tests to pass on edge rails
(1b0afb31dfc71674b054459c2e0418ca3a709467). Over a hundred tests fail
with this (or similar) error message.

  1) Error:
test_error_for_block(ActiveRecordHelperTest):
NameError: uninitialized constant I18n::Backend::Simple::Dispatcher
    ./test/../../activesupport/lib/active_support/dependencies.rb:
102:in `const_missing'
    ./test/../../activesupport/lib/active_support/vendor/i18n-0.0.1/
i18n/backend/simple.rb:10:in `initialize'
    ./test/../../activesupport/lib/active_support/vendor/i18n-0.0.1/
i18n.rb:20:in `new'
    ./test/../../activesupport/lib/active_support/vendor/i18n-0.0.1/
i18n.rb:20:in `backend'
    ./test/../../activesupport/lib/active_support/vendor/i18n-0.0.1/
i18n.rb:153:in `t'
    ./test/../lib/action_view/helpers/active_record_helper.rb:197:in
`error_messages_for'
    ./test/../../activesupport/lib/active_support/core_ext/object/
misc.rb:63:in `with_options'
    ./test/../lib/action_view/helpers/active_record_helper.rb:192:in
`error_messages_for'
    ./test/template/active_record_helper_test.rb:192:in
`test_error_for_block'
    ./test/../../activesupport/lib/active_support/testing/
setup_and_teardown.rb:94:in `__send__'
    ./test/../../activesupport/lib/active_support/testing/
setup_and_teardown.rb:94:in `run'

I have the latest i18n gem installed, so I'm not sure what the problem
could be. Anyone else having this problem?

Yeah, I see this too. Fix is forthcoming.