Improve the desugaring of -XStrict

Trac #14035 showed that -XStrict was generating some TERRIBLE
desugarings, espcially for bindings with INLINE pragmas. Reason: with
-XStrict, all AbsBinds (even for non-recursive functions) went via the
general-case deguaring for AbsBinds, namely "generate a tuple and
select from it", even though in this case there was only one variable
in the tuple.  And that in turn interacts terribly badly with INLINE
pragmas.

This patch cleans things up:

* I killed off AbsBindsSig completely, in favour of a boolean flag
  abs_sig in AbsBinds.  See Note [The abs_sig field of AbsBinds]

  This allowed me to delete lots of code; and instance-method
  declarations can enjoy the benefits too.  (They could have
  before, but no one had changed them to use AbsBindsSig.)

* I refactored all the AbsBinds handling in DsBinds into a new
  function DsBinds.dsAbsBinds.  This allowed me to handle the
  strict case uniformly

1 files changed, 0 insertions, 1 deletions

diff --git a/utils/ghctags/Main.hs b/utils/ghctags/Main.hs
index c4db3ca212..f74c7514db 100644
--- a/utils/ghctags/Main.hs
+++ b/utils/ghctags/Main.hs
@@ -284,7 +284,6 @@ boundThings modname lbinding =
     PatBind { pat_lhs = lhs } -> patThings lhs []
     VarBind { var_id = id } -> [FoundThing modname (getOccString id) (startOfLocated lbinding)]
     AbsBinds { }    -> [] -- nothing interesting in a type abstraction
-    AbsBindsSig { } -> []
     PatSynBind PSB{ psb_id = id } -> [thing id]
   where thing = foundOfLName modname
         patThings lpat tl =