getChanContents BlockedIndefinitelyOnMVar on 7.10 RC1

All of the stanzas work on 7.8.3, but the middle one works incorrectly on 7.10:

module Main where

import Control.Concurrent.Chan
import Control.Monad

main = do
    io <- newChan
    let inp = [0] :: [Int]
    mapM_ (writeChan io) inp
{-
    -- WORKS:
    outp <- getChanContents io
    if 0 == head outp
        then putStrLn "OK"
        else error $ "Smoke test failed"
-}
    -- BROKEN ON 7.10 (BlockedIndefinitelyOnMVar):
    outp <- getChanContents io
    if and (zipWith (==) inp outp)
        then putStrLn "OK"
        else error $ "Smoke test failed"
{-
    -- WORKS:
    forM_ inp $ \xIn-> do
        xOut <- readChan io
        unless (xIn == xOut) $
            error $ "Smoke test failed"
-}

I first noticed the behavior in a Chan-like library I wrote, whose internals are completely different from Chan, but where the getChanContents is a copy-paste from Chan. So I assume it has something to do with unsafeInterleaveIO.

Trac metadata

Trac field	Value
Version	7.10.1-rc1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	libraries/base
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	ekmett, hvr
Operating system
Architecture