#9128: Possible bug in strictness analyzer when where clause declared NOINLINE -----------------------------------------+--------------------------------- Reporter: aalevy | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: strictness bytestring | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Runtime Blocked By: | crash Related Tickets: | Test Case: | Blocking: -----------------------------------------+--------------------------------- I've encountered the following error message using a relatively straight forward library that wraps postgresql-simple in certain edge cases: {{{ *** Exception: Oops! Entered absent arg a_sYDl{v} [lid] bytestring-0.10.4.0:Data.ByteString.Internal.ByteString{tc r5T} }}} This happens on an invocation of a function, `dbSelect` under certain compilation conditions: {{{ dbSelect :: (Model a) => Connection -> DBSelect a -> IO [a] {-# INLINE #-} dbSelect conn dbs = map lookupRow <$> query_ conn q where {-# NOINLINE #-} q = renderDBSelect dbs }}} A DBSelect is just a data-structure with different `Query` (wrapper around strict bytestring) fields for clauses in a SQL select query. `renderDBSelect` generates a single `Query` value from the DBSelect (by way of contructing a Blaze.Builder as an intermediate step). When compiled with no optimizations, this works fine, no issues. With -O1, I get the error above. The errors goes away, if I compile with -fno- strictness or remove the NOINLINE *or* INLINE pragmas. We've worked around this for now in the library by removgin the NOINLINE pragmas, but tracking this down it seems like the strictness analyzer might be falsly assuming `q` is never actually evaluated. For reference, this is a commit that still exhibits the bug: https://github.com/alevy/postgresql- orm/tree/93075d56ae5ffeb8f80ecc8c01436713c2656a6b I've also attached a small test application that excercises the bug. Because of how the library sets up a scratch database, the test application requires postgres and pg_ctl to be available in the path. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9128 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler