[project @ 2000-05-25 12:41:14 by simonpj]

~~~~~~~~~~~~
		Apr/May 2000
		~~~~~~~~~~~~

This is a pretty big commit!  It adds stuff I've been working on
over the last month or so.  DO NOT MERGE IT WITH 4.07!

Interface file formats have changed a little; you'll need
to make clean before remaking.

						Simon PJ

Recompilation checking
~~~~~~~~~~~~~~~~~~~~~~
Substantial improvement in recompilation checking.  The version management
is now entirely internal to GHC.  ghc-iface.lprl is dead!

The trick is to generate the new interface file in two steps:
  - first convert Types etc to HsTypes etc, and thereby
	build a new ParsedIface
  - then compare against the parsed (but not renamed) version of the old
	interface file
Doing this meant adding code to convert *to* HsSyn things, and to
compare HsSyn things for equality.  That is the main tedious bit.

Another improvement is that we now track version info for
fixities and rules, which was missing before.


Interface file reading
~~~~~~~~~~~~~~~~~~~~~~
Make interface files reading more robust.
  * If the old interface file is unreadable, don't fail. [bug fix]

  * If the old interface file mentions interfaces
    that are unreadable, don't fail. [bug fix]

  * When we can't find the interface file,
    print the directories we are looking in.  [feature]


Type signatures
~~~~~~~~~~~~~~~
  * New flag -ddump-types to print type signatures


Type pruning
~~~~~~~~~~~~
When importing
	data T = T1 A | T2 B | T3 C
it seems excessive to import the types A, B, C as well, unless
the constructors T1, T2 etc are used.  A,B,C might be more types,
and importing them may mean reading more interfaces, and so on.
 So the idea is that the renamer will just import the decl
	data T
unless one of the constructors is used.  This turns out to be quite
easy to implement.  The downside is that we must make sure the
constructors are always available if they are really needed, so
I regard this as an experimental feature.


Elimininate ThinAir names
~~~~~~~~~~~~~~~~~~~~~~~~~
Eliminate ThinAir.lhs and all its works.  It was always a hack, and now
the desugarer carries around an environment I think we can nuke ThinAir
altogether.

As part of this, I had to move all the Prelude RdrName defns from PrelInfo
to PrelMods --- so I renamed PrelMods as PrelNames.

I also had to move the builtinRules so that they are injected by the renamer
(rather than appearing out of the blue in SimplCore).  This is if anything simpler.

Miscellaneous
~~~~~~~~~~~~~
* Tidy up the data types involved in Rules

* Eliminate RnEnv.better_provenance; use Name.hasBetterProv instead

* Add Unique.hasKey :: Uniquable a => a -> Unique -> Bool
  It's useful in a lot of places

* Fix a bug in interface file parsing for __U[!]

1 files changed, 9 insertions, 8 deletions

diff --git a/ghc/compiler/deSugar/DsCCall.lhs b/ghc/compiler/deSugar/DsCCall.lhs
index 11ca5a093a..6d488c44e7 100644
--- a/ghc/compiler/deSugar/DsCCall.lhs
+++ b/ghc/compiler/deSugar/DsCCall.lhs
@@ -28,7 +28,7 @@ import DataCon		( DataCon, splitProductType_maybe, dataConSourceArity, dataConWr
 import CallConv
 import Type		( isUnLiftedType, splitAlgTyConApp_maybe, mkFunTys,
 			  splitTyConApp_maybe, tyVarsOfType, mkForAllTys, 
-			  isNewType, repType, isUnLiftedType, mkFunTy,
+			  isNewType, repType, isUnLiftedType, mkFunTy, mkTyConApp,
 			  Type
 			)
 import PprType		( {- instance Outputable Type -} )
@@ -36,14 +36,15 @@ import TysPrim		( byteArrayPrimTy, realWorldStatePrimTy,
 			  byteArrayPrimTyCon, mutableByteArrayPrimTyCon, intPrimTy
 			)
 import TysWiredIn	( unitDataConId, stringTy,
-			  unboxedPairDataCon,
-			  mkUnboxedTupleTy, unboxedTupleCon,
+			  unboxedSingletonDataCon, unboxedPairDataCon,
+			  unboxedSingletonTyCon, unboxedPairTyCon,
+			  mkTupleTy, tupleCon,
 			  boolTy, trueDataCon, falseDataCon, trueDataConId, falseDataConId,
 			  unitTy
 			)
 import Literal		( mkMachInt )
 import CStrings		( CLabelString )
-import Unique		( Unique, Uniquable(..), ioTyConKey )
+import Unique		( Unique, Uniquable(..), hasKey, ioTyConKey )
 import VarSet		( varSetElems )
 import Outputable
 \end{code}
@@ -212,7 +213,7 @@ boxResult result_ty
   = case splitAlgTyConApp_maybe result_ty of
 
 	-- The result is IO t, so wrap the result in an IO constructor
-	Just (io_tycon, [io_res_ty], [io_data_con]) | getUnique io_tycon == ioTyConKey
+	Just (io_tycon, [io_res_ty], [io_data_con]) | io_tycon `hasKey` ioTyConKey
 		-> mk_alt return_result 
 			  (resultWrapper io_res_ty)	`thenDs` \ (ccall_res_ty, the_alt) ->
 		   newSysLocalDs realWorldStatePrimTy	 `thenDs` \ state_id ->
@@ -247,8 +248,8 @@ boxResult result_ty
 	  newSysLocalDs realWorldStatePrimTy	`thenDs` \ state_id ->
 	  let
 		the_rhs      = return_result (Var state_id) (wrap_result (panic "boxResult"))
-		ccall_res_ty = mkUnboxedTupleTy 1 [realWorldStatePrimTy]
-		the_alt      = (DataAlt (unboxedTupleCon 1), [state_id], the_rhs)
+		ccall_res_ty = mkTyConApp unboxedSingletonTyCon [realWorldStatePrimTy]
+		the_alt      = (DataAlt unboxedSingletonDataCon, [state_id], the_rhs)
 	  in
 	  returnDs (ccall_res_ty, the_alt)
 
@@ -258,7 +259,7 @@ boxResult result_ty
 	  newSysLocalDs prim_res_ty 		`thenDs` \ result_id ->
 	  let
 		the_rhs      = return_result (Var state_id) (wrap_result (Var result_id))
-		ccall_res_ty = mkUnboxedTupleTy 2 [realWorldStatePrimTy, prim_res_ty]
+		ccall_res_ty = mkTyConApp unboxedPairTyCon [realWorldStatePrimTy, prim_res_ty]
 		the_alt	     = (DataAlt unboxedPairDataCon, [state_id, result_id], the_rhs)
 	  in
 	  returnDs (ccall_res_ty, the_alt)