Re: BoxedRep UNPACK pragma

On Sat, Aug 12, 2023 at 5:20 PM Brandon Allbery wrote:

The warning sounds correct to me: `Maybe` has two constructors?

It says at https://downloads.haskell.org/ghc/latest/docs/users_guide/exts/pragmas.html#... "Since 9.6.1, data types with multiple constructors can also be unpacked, effectively transforming the field into an unboxed sum of the unpackings of each constructor (see UnboxedSums)."

On Sat, Aug 12, 2023 at 10:25 AM Alan & Kim Zimmerman wrote:

...

I have seen the following warning on master for some time

compiler/GHC/Core/TyCon.hs:1540:5: warning: • Ignoring unusable UNPACK pragma on the first argument of ‘BoxedRep’ • In the definition of data constructor ‘BoxedRep’ In the data type declaration for ‘PrimRep’ | 1540 | | BoxedRep {-# UNPACK #-} !(Maybe Levity) -- ^ Boxed, heap value | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Is it something that needs to be fixed? Can the code be updated to remove the warning?

Alan _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

-- brandon s allbery kf8nh allbery.b@gmail.com _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs