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Invariants from a successful nested transaction should be merged with the parent.

import Control.Concurrent
import Control.Concurrent.STM

main = do
    x <- atomically $
        do a <- newTVar True
           (always (readTVar a) >> retry) `orElse` return ()
           return a
    atomically (writeTVar x False) -- Should not and does not fail

    y <- atomically $
        do a <- newTVar True
           always (readTVar a) `orElse` return ()
           return a
    atomically (writeTVar y False) -- Should fail, but does not!

    putStrLn "Ahhh!"

    z <- atomically $
        do a <- newTVar True
           always (readTVar a)
           return a
    atomically (writeTVar z False) -- should and does fail

I know how to fix this. I'll have a patch with some tests and a fix soon.

Trac metadata

Trac field	Value
Version	7.6.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Runtime System
Test case
Differential revisions
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