Incoming fails on i686 linux with optimizations

[brson]

The bots are currently failing like so

running 1 test
rust: task failed at 'int 0 out of range for this architecture', /home/brian/dev/rust4/src/libstd/ebml.rs:349
test flatpipes::test::test_serializing_pipes ... FAILED

failures:
    flatpipes::test::test_serializing_pipes

I bisected to e1be9ae, which changes how fail! works.

[Aatch]

Closing since I'm almost certain that test is either gone, or passes.

[brson]

This continues to be a source of breakage on incoming. Right now the failure is in rpass/auto-encode

[brson]

run-pass/auto-encode is xfailed now

[brson]

my issue-6122 branch contains a reduced test case under run-pass/issue-6122

[toddaaro]

@brson: incoming has been poofed, so I'm not sure what the status of this is. Bors has been churning away and the tree is green, so does the problem still arise?

[emberian]

The test passes locally for me with some updating. Pushed it to try, will see how it falls.