[Haskell-cafe] Yay 6.12.1!

Evan Laforge qdunkan at gmail.com
Tue Dec 15 05:04:18 EST 2009

So far, this new release has let me remove:

- The new "Import of xyz is redundant" warning pointed out tons of cruft in my
imports: 117 of them!  Apparently it's better than the 6.10 algorithm.  It's
amazing how much cruft builds up in import lists over time even with -Wall.

One issue is that I can still get a spurious warning from it: if I have
'import qualified Text.Read as Read' and then have some Read instances, it will
think the import is redundant even though it won't compile without it
(`readPrec' is not a (visible) method of class `Read').  The interesting
thing is that even though I'm importing it qualified, I write the readPrec in
the instance without qualification since 'instance Read X where Read.readPrec =
...' is not allowed.  So maybe ghc is confused by that since it doesn't see a
Read. anywhere.  Importing unqualified doesn't make the warning.

- I removed {-# OPTIONS_GHC -fno-warn-unused-imports #-} from a lot of files,
now that the bugs that make spurious import warns are fixed.  And the bogus
warnings with view patterns are gone.

- I removed a local version of Data.Map, now that toDescList is in.

- Passing -I/path/to/ghc/include to hsc2hs to get it to include HsFFI.h seems
to no longer be necessary.

- The warnings "-#include is deprecated: No longer has any effect" are
not quite right,
because they are reuired by hsc2hs, and in fact hsc2hs is inserting {-# INCLUDE
"c_interface.h" #-}.  Maybe it should be updated to not do that?

I know these are small improvements and not as cool as faster parallelism, but I
want so say that these little fixes are noticed and much appreciated, and give
a big thank you to the Simons and Ian and anyone else involved with this
release.  It's so satisfying to finally see a warning free compile!

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