1. 02 Apr, 2004 1 commit
    • simonpj's avatar
      [project @ 2004-04-02 12:38:33 by simonpj] · bc7bd6e3
      simonpj authored
      A preliminary step towards being able to identify existential
      type variables separately.  That in turn helps when resolving
      overloading; I think we want to resolve overloading without
      worrying about what these type variables might instantiate to.
      bc7bd6e3
  2. 17 Mar, 2004 2 commits
    • simonpj's avatar
      [project @ 2004-03-17 13:59:06 by simonpj] · af5a2151
      simonpj authored
      ------------------------
      	More newtype clearing up
      	------------------------
      
      * Change the representation of TyCons so that it accurately reflects
      	* data     (0 or more constrs)
      	* newtype  (1 constr)
      	* abstract (unknown)
        Replaces DataConDetails and AlgTyConFlavour with AlgTyConRhs
      
      * Add IfaceSyn.IfaceConDecls, a kind of stripped-down analogue
        of AlgTyConRhs
      
      * Move NewOrData from BasicTypes to HsDecl (it's now an HsSyn thing)
      
      * Arrange that Type.newTypeRep and splitRecNewType_maybe unwrap just
        one layer of new-type-ness, leaving the caller to recurse.
      
        This still leaves typeRep and repType in Type.lhs; these functions
        are still vaguely disturbing and probably should get some attention.
      
      Lots of knock-on changes.  Fixes bug in ds054.
      af5a2151
    • simonpj's avatar
      [project @ 2004-03-17 08:54:19 by simonpj] · a6001411
      simonpj authored
      Use sub-kind rather than kind-equality check in matchTys,
      just as we do in TcUnify.  This is someting I failed to
      do when shifting to the funky new kind representation.
      a6001411
  3. 25 Feb, 2004 1 commit
    • simonpj's avatar
      [project @ 2004-02-25 13:54:30 by simonpj] · 49ac6c39
      simonpj authored
      Yet another fix to the -Onot optimisation that hides data type
      representations in .hi files.
      
      1.  Expose the representation if any fields are exposed
      
      2.  Don't expose newtypes whose data-cons are abstract, unless the
          rep type is a FFI type.  (Previously we were more conservative
          and always exposed newtypes, just in case of a foreign decl.)
      49ac6c39
  4. 05 Jan, 2004 1 commit
  5. 30 Dec, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-12-30 16:29:17 by simonpj] · f714e6b6
      simonpj authored
      ----------------------------
              Re-do kind inference (again)
      	----------------------------
      
         [WARNING: interface file binary representation has
         (as usual) changed slightly; recompile your libraries!]
      
      Inspired by the lambda-cube, for some time GHC has used
      	type Kind = Type
      That is, kinds were represented by the same data type as types.
      
      But GHC also supports unboxed types and unboxed tuples, and these
      complicate the kind system by requiring a sub-kind relationship.
      Notably, an unboxed tuple is acceptable as the *result* of a
      function but not as an *argument*.  So we have the following setup:
      
      		 ?
      		/ \
      	       /   \
      	      ??   (#)
      	     /  \
                  *   #
      
      where	*    [LiftedTypeKind]   means a lifted type
      	#    [UnliftedTypeKind] means an unlifted type
      	(#)  [UbxTupleKind]     means unboxed tuple
      	??   [ArgTypeKind]      is the lub of *,#
      	?    [OpenTypeKind]	means any type at all
      
      In particular:
      
        error :: forall a:?. String -> a
        (->)  :: ?? -> ? -> *
        (\(x::t) -> ...)	Here t::?? (i.e. not unboxed tuple)
      
      All this has beome rather difficult to accommodate with Kind=Type, so this
      commit splits the two.
      
        * Kind is a distinct type, defined in types/Kind.lhs
      
        * IfaceType.IfaceKind disappears: we just re-use Kind.Kind
      
        * TcUnify.unifyKind is a distinct unifier for kinds
      
        * TyCon no longer needs KindCon and SuperKindCon variants
      
        * TcUnify.zapExpectedType takes an expected Kind now, so that
          in TcPat.tcMonoPatBndr we can express that the bound variable
          must have an argTypeKind (??).
      
      The big change is really that kind inference is much more systematic and
      well behaved.  In particular, a kind variable can unify only with a
      "simple kind", which is built from * and (->).  This deals neatly
      with awkward questions about how we can combine sub-kinding with type
      inference.
      
      Lots of small consequential changes, especially to the kind-checking
      plumbing in TcTyClsDecls.  (We played a bit fast and loose before, and
      now we have to be more honest, in particular about how kind inference
      works for type synonyms.  They can have kinds like (* -> #), so
      
      This cures two long-standing SourceForge bugs
      
      * 753777 (tcfail115.hs), which used erroneously to pass,
        but crashed in the code generator
            type T a = Int -> (# Int, Int #)
            f :: T a -> T a
            f t = \x -> case t x of r -> r
      
      * 753780 (tc167.hs), which used erroneously to fail
            f :: (->) Int# Int#
      
      
      Still, the result is not entirely satisfactory.  In particular
      
      * The error message from tcfail115 is pretty obscure
      
      * SourceForge bug 807249 (Instance match failure on openTypeKind)
        is not fixed.  Alas.
      f714e6b6
  6. 03 Nov, 2003 1 commit
  7. 31 Oct, 2003 1 commit
  8. 30 Oct, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-10-30 16:01:49 by simonpj] · 57573e7e
      simonpj authored
      This commit does a long-overdue tidy-up
      
      * Remove PprType (gets rid of one more bunch of hi-boot files)
      
      * Put pretty-printing for types in TypeRep
      
      * Make a specialised pretty-printer for Types, rather than
        converting to IfaceTypes and printing those
      57573e7e
  9. 21 Oct, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-10-21 12:54:17 by simonpj] · 1bade0c9
      simonpj authored
      1. A tiresome change to HsType, to keep a record of whether or not
         the HsForAll was originally explicitly-quantified.  This is
         solely so that the type checker can print out messages that
         show the source code the programmer wrote.  Tiresome but
         easy.
      
      2. Improve reporting of kind errors.
      1bade0c9
  10. 13 Oct, 2003 1 commit
  11. 10 Oct, 2003 1 commit
  12. 09 Oct, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-10-09 11:58:39 by simonpj] · 98688c6e
      simonpj authored
      -------------------------
      		GHC heart/lung transplant
      		-------------------------
      
      This major commit changes the way that GHC deals with importing
      types and functions defined in other modules, during renaming and
      typechecking.  On the way I've changed or cleaned up numerous other
      things, including many that I probably fail to mention here.
      
      Major benefit: GHC should suck in many fewer interface files when
      compiling (esp with -O).  (You can see this with -ddump-rn-stats.)
      
      It's also some 1500 lines of code shorter than before.
      
      **	So expect bugs!  I can do a 3-stage bootstrap, and run
      **	the test suite, but you may be doing stuff I havn't tested.
      ** 	Don't update if you are relying on a working HEAD.
      
      
      In particular, (a) External Core and (b) GHCi are very little tested.
      
      	But please, please DO test this version!
      
      
      	------------------------
      		Big things
      	------------------------
      
      Interface files, version control, and importing declarations
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      * There is a totally new data type for stuff that lives in interface files:
      	Original names			IfaceType.IfaceExtName
      	Types				IfaceType.IfaceType
      	Declarations (type,class,id)	IfaceSyn.IfaceDecl
      	Unfoldings			IfaceSyn.IfaceExpr
        (Previously we used HsSyn for type/class decls, and UfExpr for unfoldings.)
        The new data types are in iface/IfaceType and iface/IfaceSyn.  They are
        all instances of Binary, so they can be written into interface files.
        Previous engronkulation concering the binary instance of RdrName has
        gone away -- RdrName is not an instance of Binary any more.  Nor does
        Binary.lhs need to know about the ``current module'' which it used to,
        which made it specialised to GHC.
      
        A good feature of this is that the type checker for source code doesn't
        need to worry about the possibility that we might be typechecking interface
        file stuff.  Nor does it need to do renaming; we can typecheck direct from
        IfaceSyn, saving a whole pass (module TcIface)
      
      * Stuff from interface files is sucked in *lazily*, rather than being eagerly
        sucked in by the renamer. Instead, we use unsafeInterleaveIO to capture
        a thunk for the unfolding of an imported function (say).  If that unfolding
        is every pulled on, TcIface will scramble over the unfolding, which may
        in turn pull in the interface files of things mentioned in the unfolding.
      
        The External Package State is held in a mutable variable so that it
        can be side-effected by this lazy-sucking-in process (which may happen
        way later, e.g. when the simplifier runs).   In effect, the EPS is a kind
        of lazy memo table, filled in as we suck things in.  Or you could think
        of it as a global symbol table, populated on demand.
      
      * This lazy sucking is very cool, but it can lead to truly awful bugs. The
        intent is that updates to the symbol table happen atomically, but very bad
        things happen if you read the variable for the table, and then force a
        thunk which updates the table.  Updates can get lost that way. I regret
        this subtlety.
      
        One example of the way it showed up is that the top level of TidyPgm
        (which updates the global name cache) to be much more disciplined about
        those updates, since TidyPgm may itself force thunks which allocate new
        names.
      
      * Version numbering in interface files has changed completely, fixing
        one major bug with ghc --make.  Previously, the version of A.f changed
        only if A.f's type and unfolding was textually different.  That missed
        changes to things that A.f's unfolding mentions; which was fixed by
        eagerly sucking in all of those things, and listing them in the module's
        usage list.  But that didn't work with --make, because they might have
        been already sucked in.
      
        Now, A.f's version changes if anything reachable from A.f (via interface
        files) changes.  A module with unchanged source code needs recompiling
        only if the versions of any of its free variables changes. [This isn't
        quite right for dictionary functions and rules, which aren't mentioned
        explicitly in the source.  There are extensive comments in module MkIface,
        where all version-handling stuff is done.]
      
      * We don't need equality on HsDecls any more (because they aren't used in
        interface files).  Instead we have a specialised equality for IfaceSyn
        (eqIfDecl etc), which uses IfaceEq instead of Bool as its result type.
        See notes in IfaceSyn.
      
      * The horrid bit of the renamer that tried to predict what instance decls
        would be needed has gone entirely.  Instead, the type checker simply
        sucks in whatever instance decls it needs, when it needs them.  Easy!
      
        Similarly, no need for 'implicitModuleFVs' and 'implicitTemplateHaskellFVs'
        etc.  Hooray!
      
      
      Types and type checking
      ~~~~~~~~~~~~~~~~~~~~~~~
      * Kind-checking of types is far far tidier (new module TcHsTypes replaces
        the badly-named TcMonoType).  Strangely, this was one of my
        original goals, because the kind check for types is the Right Place to
        do type splicing, but it just didn't fit there before.
      
      * There's a new representation for newtypes in TypeRep.lhs.  Previously
        they were represented using "SourceTypes" which was a funny compromise.
        Now they have their own constructor in the Type datatype.  SourceType
        has turned back into PredType, which is what it used to be.
      
      * Instance decl overlap checking done lazily.  Consider
      	instance C Int b
      	instance C a Int
        These were rejected before as overlapping, because when seeking
        (C Int Int) one couldn't tell which to use.  But there's no problem when
        seeking (C Bool Int); it can only be the second.
      
        So instead of checking for overlap when adding a new instance declaration,
        we check for overlap when looking up an Inst.  If we find more than one
        matching instance, we see if any of the candidates dominates the others
        (in the sense of being a substitution instance of all the others);
        and only if not do we report an error.
      
      
      
      	------------------------
      	     Medium things
      	------------------------
      
      * The TcRn monad is generalised a bit further.  It's now based on utils/IOEnv.lhs,
        the IO monad with an environment.  The desugarer uses the monad too,
        so that anything it needs can get faulted in nicely.
      
      * Reduce the number of wired-in things; in particular Word and Integer
        are no longer wired in.  The latter required HsLit.HsInteger to get a
        Type argument.  The 'derivable type classes' data types (:+:, :*: etc)
        are not wired in any more either (see stuff about derivable type classes
        below).
      
      * The PersistentComilerState is now held in a mutable variable
        in the HscEnv.  Previously (a) it was passed to and then returned by
        many top-level functions, which was painful; (b) it was invariably
        accompanied by the HscEnv.  This change tidies up top-level plumbing
        without changing anything important.
      
      * Derivable type classes are treated much more like 'deriving' clauses.
        Previously, the Ids for the to/from functions lived inside the TyCon,
        but now the TyCon simply records their existence (with a simple boolean).
        Anyone who wants to use them must look them up in the environment.
      
        This in turn makes it easy to generate the to/from functions (done
        in types/Generics) using HsSyn (like TcGenDeriv for ordinary derivings)
        instead of CoreSyn, which in turn means that (a) we don't have to figure
        out all the type arguments etc; and (b) it'll be type-checked for us.
        Generally, the task of generating the code has become easier, which is
        good for Manuel, who wants to make it more sophisticated.
      
      * A Name now says what its "parent" is. For example, the parent of a data
        constructor is its type constructor; the parent of a class op is its
        class.  This relationship corresponds exactly to the Avail data type;
        there may be other places we can exploit it.  (I made the change so that
        version comparison in interface files would be a bit easier; but in
        fact it tided up other things here and there (see calls to
        Name.nameParent).  For example, the declaration pool, of declararations
        read from interface files, but not yet used, is now keyed only by the 'main'
        name of the declaration, not the subordinate names.
      
      * New types OccEnv and OccSet, with the usual operations.
        OccNames can be efficiently compared, because they have uniques, thanks
        to the hashing implementation of FastStrings.
      
      * The GlobalRdrEnv is now keyed by OccName rather than RdrName.  Not only
        does this halve the size of the env (because we don't need both qualified
        and unqualified versions in the env), but it's also more efficient because
        we can use a UniqFM instead of a FiniteMap.
      
        Consequential changes to Provenance, which has moved to RdrName.
      
      * External Core remains a bit of a hack, as it was before, done with a mixture
        of HsDecls (so that recursiveness and argument variance is still inferred),
        and IfaceExprs (for value declarations).  It's not thoroughly tested.
      
      
      	------------------------
      	     Minor things
      	------------------------
      
      * DataCon fields dcWorkId, dcWrapId combined into a single field
        dcIds, that is explicit about whether the data con is a newtype or not.
        MkId.mkDataConWorkId and mkDataConWrapId are similarly combined into
        MkId.mkDataConIds
      
      * Choosing the boxing strategy is done for *source* type decls only, and
        hence is now in TcTyDecls, not DataCon.
      
      * WiredIn names are distinguished by their n_sort field, not by their location,
        which was rather strange
      
      * Define Maybes.mapCatMaybes :: (a -> Maybe b) -> [a] -> [b]
        and use it here and there
      
      * Much better pretty-printing of interface files (--show-iface)
      
      Many, many other small things.
      
      
      	------------------------
      	     File changes
      	------------------------
      * New iface/ subdirectory
      * Much of RnEnv has moved to iface/IfaceEnv
      * MkIface and BinIface have moved from main/ to iface/
      * types/Variance has been absorbed into typecheck/TcTyDecls
      * RnHiFiles and RnIfaces have vanished entirely.  Their
        work is done by iface/LoadIface
      * hsSyn/HsCore has gone, replaced by iface/IfaceSyn
      * typecheck/TcIfaceSig has gone, replaced by iface/TcIface
      * typecheck/TcMonoType has been renamed to typecheck/TcHsType
      * basicTypes/Var.hi-boot and basicTypes/Generics.hi-boot have gone altogether
      98688c6e
  13. 23 Sep, 2003 1 commit
  14. 20 Jun, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-06-20 11:14:18 by simonpj] · 1f861358
      simonpj authored
      ------------------------------
      	Fix a small quantification bug
      	------------------------------
      
      We were quantifying over too few type variables, because fdPredsOfInsts was
      being too eager to discard predicates. This only affects rather obscure
      programs.  Here's the one Iavor found:
      
      	class C a b where f :: a -> b
      	g x = fst (f x)
      
      We want to get the type
         	g :: forall a b c.  C a (b,c) => a -> b
      but GHC 6.0 bogusly gets
         	g :: forall a b.  C a (b,()) => a -> b
      
      A test is in should_compile/tc168
      1f861358
  15. 16 Jun, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-06-16 15:32:16 by simonpj] · f5fbd41c
      simonpj authored
      --------------------------
      	Remove some wired-in types
      	--------------------------
      
      ptrTyCon, funPtrTyCon, addrTyCon, stablePtrTyCon have no business
      being wired in. This commit makes them into knownKey Names, which
      is much better.
      f5fbd41c
  16. 29 May, 2003 1 commit
    • sof's avatar
      [project @ 2003-05-29 14:39:26 by sof] · a7d8f437
      sof authored
      Support for interop'ing with .NET via FFI declarations along the
      lines of what Hugs98.NET offers, see
      
       http://haskell.org/pipermail/cvs-hugs/2003-March/001723.html
      
      for FFI decl details.
      
      To enable, configure with --enable-dotnet + have a look
      in ghc/rts/dotnet/Makefile for details of what tools are needed to
      build the .NET interop layer (tools from VS.NET / Framework SDK.)
      
      The commit doesn't include some library additions + wider-scale
      testing is required before this extension can be regarded as available
      for general use. 'foreign import dotnet' is currently only supported
      by the C backend.
      a7d8f437
  17. 16 Apr, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-04-16 13:34:13 by simonpj] · 221b6b69
      simonpj authored
      ----------------------------------
       Use the Infer/Check idea for typechecking higher-rank types
      	----------------------------------
      
      The main idea is that
      
      	data Expected ty = Infer (TcRef ty) | Check ty
      
      	tcMonoExpr :: Expr -> Expected TcRhoType -> TcM Expra
      
      
      This "Expected" type tells tcMonoExpr whether it's doing inference or
      checking.  It replaces the "HoleTv" flavour of type variable.
      
      This actually leads to slightly more lines of code, but it's much
      clearer, and the new type distinctions showed up several subtle bugs
      in the previous implementation.  It all arose out of writing the
      prototype implementation for the paper.
      
      Error messages wibble around a little bit.  I'm not quite certain why!  But the
      changes look like improvements to me.
      221b6b69
  18. 20 Feb, 2003 1 commit
  19. 12 Feb, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-02-12 15:01:31 by simonpj] · 42b63073
      simonpj authored
      -------------------------------------
        Big upheaval to the way that constructors are named
      	-------------------------------------
      
      This commit enshrines the new story for constructor names.  We could never
      really get External Core to work nicely before, but now it does.
      
      The story is laid out in detail in the Commentary
      	ghc/docs/comm/the-beast/data-types.html
      so I will not repeat it here.
      
      	[Manuel: the commentary isn't being updated, apparently.]
      
      However, the net effect is that in Core and in External Core, contructors look
      like constructors, and the way things are printed is all consistent.
      
      It is a fairly pervasive change (which is why it has been so long postponed),
      but I hope the question is now finally closed.
      
      All the libraries compile etc, and I've run many tests, but doubtless there will
      be some dark corners.
      42b63073
  20. 04 Feb, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-02-04 15:09:38 by simonpj] · 957bf375
      simonpj authored
      -------------------------------------
      	Remove all vestiges of usage analysis
      	-------------------------------------
      
      This commit removes a large blob of usage-analysis-related code, almost
      all of which was commented out.
      
      Sadly, it doesn't look as if Keith is going to have enough time to polish it
      up, and in any case the actual performance benefits (so far as we can measure
      them) turned out to be pretty modest (a few percent).
      
      So, with regret, I'm chopping it all out.  It's still there in the repository
      if anyone wants go hack on it.  And Tobias Gedell at Chalmers is implementing
      a different analysis, via External Core.
      957bf375
  21. 23 Jan, 2003 1 commit
    • simonmar's avatar
      [project @ 2003-01-23 16:01:33 by simonmar] · 6873f3d4
      simonmar authored
      Allow FFI declarations to have polymorphic types. eg:
      
      foreign import ccall unsafe "stdlib.h &free" pFree :: FunPtr (Ptr a -> IO ())
      
      (the change actually removed a line, the extra lines are because I
      reformatted an import declaration).
      6873f3d4
  22. 11 Nov, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-11-11 10:53:28 by simonpj] · 0adb7175
      simonpj authored
      ------------------
        	   Fix a newtype-deriving bug
      		------------------
      
      The new newtype-deriving mechanism was erroneously using the
      *representation type* of the newtype.  The rep type looks through all
      ihtermediate newtypes, so that is wrong.  See Note [newtype
      representation] in TcDeriv.lhs
      
      deriving/should_run/drvrun013 now tests for this.
      0adb7175
  23. 13 Sep, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-09-13 15:02:25 by simonpj] · 9af77fa4
      simonpj authored
      --------------------------------------
      	Make Template Haskell into the HEAD
      	--------------------------------------
      
      This massive commit transfers to the HEAD all the stuff that
      Simon and Tim have been doing on Template Haskell.  The
      meta-haskell-branch is no more!
      
      WARNING: make sure that you
      
        * Update your links if you are using link trees.
          Some modules have been added, some have gone away.
      
        * Do 'make clean' in all library trees.
          The interface file format has changed, and you can
          get strange panics (sadly) if GHC tries to read old interface files:
          e.g.  ghc-5.05: panic! (the `impossible' happened, GHC version 5.05):
      	  Binary.get(TyClDecl): ForeignType
      
        * You need to recompile the rts too; Linker.c has changed
      
      
      However the libraries are almost unaltered; just a tiny change in
      Base, and to the exports in Prelude.
      
      
      NOTE: so far as TH itself is concerned, expression splices work
      fine, but declaration splices are not complete.
      
      
      		---------------
      		The main change
      		---------------
      
      The main structural change: renaming and typechecking have to be
      interleaved, because we can't rename stuff after a declaration splice
      until after we've typechecked the stuff before (and the splice
      itself).
      
      * Combine the renamer and typecheker monads into one
      	(TcRnMonad, TcRnTypes)
        These two replace TcMonad and RnMonad
      
      * Give them a single 'driver' (TcRnDriver).  This driver
        replaces TcModule.lhs and Rename.lhs
      
      * The haskell-src library package has a module
      	Language/Haskell/THSyntax
        which defines the Haskell data type seen by the TH programmer.
      
      * New modules:
      	hsSyn/Convert.hs 	converts THSyntax -> HsSyn
      	deSugar/DsMeta.hs 	converts HsSyn -> THSyntax
      
      * New module typecheck/TcSplice type-checks Template Haskell splices.
      
      		-------------
      		Linking stuff
      		-------------
      
      * ByteCodeLink has been split into
      	ByteCodeLink	(which links)
      	ByteCodeAsm	(which assembles)
      
      * New module ghci/ObjLink is the object-code linker.
      
      * compMan/CmLink is removed entirely (was out of place)
        Ditto CmTypes (which was tiny)
      
      * Linker.c initialises the linker when it is first used (no need to call
        initLinker any more).  Template Haskell makes it harder to know when
        and whether to initialise the linker.
      
      
      	-------------------------------------
      	Gathering the LIE in the type checker
      	-------------------------------------
      
      * Instead of explicitly gathering constraints in the LIE
      	tcExpr :: RenamedExpr -> TcM (TypecheckedExpr, LIE)
        we now dump the constraints into a mutable varabiable carried
        by the monad, so we get
      	tcExpr :: RenamedExpr -> TcM TypecheckedExpr
      
        Much less clutter in the code, and more efficient too.
        (Originally suggested by Mark Shields.)
      
      
      		-----------------
      		Remove "SysNames"
      		-----------------
      
      Because the renamer and the type checker were entirely separate,
      we had to carry some rather tiresome implicit binders (or "SysNames")
      along inside some of the HsDecl data structures.  They were both
      tiresome and fragile.
      
      Now that the typechecker and renamer are more intimately coupled,
      we can eliminate SysNames (well, mostly... default methods still
      carry something similar).
      
      		-------------
      		Clean up HsPat
      		-------------
      
      One big clean up is this: instead of having two HsPat types (InPat and
      OutPat), they are now combined into one.  This is more consistent with
      the way that HsExpr etc is handled; there are some 'Out' constructors
      for the type checker output.
      
      So:
      	HsPat.InPat	--> HsPat.Pat
      	HsPat.OutPat	--> HsPat.Pat
      	No 'pat' type parameter in HsExpr, HsBinds, etc
      
      	Constructor patterns are nicer now: they use
      		HsPat.HsConDetails
      	for the three cases of constructor patterns:
      		prefix, infix, and record-bindings
      
      	The *same* data type HsConDetails is used in the type
      	declaration of the data type (HsDecls.TyData)
      
      Lots of associated clean-up operations here and there.  Less code.
      Everything is wonderful.
      9af77fa4
  24. 06 Sep, 2002 2 commits
  25. 29 Jul, 2002 1 commit
  26. 20 Jun, 2002 1 commit
  27. 22 Apr, 2002 1 commit
  28. 25 Mar, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-03-25 15:08:38 by simonpj] · aaed1181
      simonpj authored
      -------------------------------
      	Fix bugs in rank-N polymorphism
      	-------------------------------
      
      Discussion with Mark showed up some bugs in the rank-N
      polymorphism stuff, especally concerning the treatment of
      'hole' type variables.
      
      See especially TcMType:
      	newHoleTyVar
      	readHoleResult
      	zapToType
      
      Also the treatment of conditionals and case branches
      is done right now, using zapToType
      aaed1181
  29. 14 Mar, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-03-14 15:27:15 by simonpj] · 1553c778
      simonpj authored
      ------------------------
      	Change
      		GlobalName --> ExternalName
      		LocalName  ->  InternalName
      	------------------------
      
      For a long time there's been terminological confusion between
      
      	GlobalName vs LocalName	 (property of a Name)
      	GlobalId vs LocalId	 (property of an Id)
      
      I've now changed the terminology for Name to be
      
      	ExternalName vs InternalName
      
      I've also added quite a bit of documentation in the Commentary.
      1553c778
  30. 12 Mar, 2002 2 commits
    • simonpj's avatar
      [project @ 2002-03-12 15:55:26 by simonpj] · 72c2f581
      simonpj authored
      ------------------------
      	Fix a type-invariant bug
      	------------------------
      
      We need to call Type.mkGenTyConApp from Type.mkAppTy, in
      case there's a partially applied type synonym.  Explanation
      with Type.mkAppTy.  All part of GHC's rather liberal treatment
      of type synonyms.
      
      Shown up by a program from Ralf Laemmel:
      
      	type Generic i o = forall x. i x -> o x
      	type Id x = x
      	comb :: Generic Id Id
      
      Test is typecheck/should_compile/tc149.hs
      72c2f581
    • simonpj's avatar
      [project @ 2002-03-12 09:12:57 by simonpj] · 49c84dec
      simonpj authored
      Comments
      49c84dec
  31. 08 Mar, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-03-08 15:50:53 by simonpj] · a170160c
      simonpj authored
      --------------------------------------
      	Lift the class-method type restriction
      	--------------------------------------
      
      Haskell 98 prohibits class method types to mention constraints on the
      class type variable, thus:
      
        class Seq s a where
          fromList :: [a] -> s a
          elem     :: Eq a => a -> s a -> Bool
      
      The type of 'elem' is illegal in Haskell 98, because it contains the
      constraint 'Eq a', which constrains only the class type variable (in
      this case 'a').
      
      This commit lifts the restriction.  The way we do that is to do a full
      context reduction (tcSimplifyCheck) step for each method separately in
      TcClassDcl.tcMethodBind, rather than doing a single context reduction
      for the whole group of method bindings.
      
      As a result, I had to reorganise the code a bit, and tidy up.
      a170160c
  32. 28 Feb, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-02-28 12:17:19 by simonpj] · 469c3333
      simonpj authored
      ---------------------------------
      	Fix a rather obscure bug in tcGen
      	---------------------------------
      
      This bug concerns deciding when a type variable "escapes",
      and hence we can't generalise it.  Our new subsumption-checking
      machinery for higher-ranked types requires a slightly
      more general approach than I had before.  The main excitement
      is in TcUnify.checkSigTyVars and its friends.
      
      As usual, I moved functions around and cleaned things up a bit;
      hence the multi-module commit.
      469c3333
  33. 13 Feb, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-02-13 15:14:06 by simonpj] · e7030995
      simonpj authored
      --------------------------------------------
      	Fix a bugs in type inference for rank-N types
      	--------------------------------------------
      
      We discovered this bug when looking at type rules!
      
      1. When type checking (e :: sigma-ty), we must specialise sigma-ty,
         else we lose the invariant that tcMonoType has.
      
      2. In tcExpr_id, we should pass in a Hole tyvar not an ordinary tyvar.
      
      As usual, I moved some functions around in consequence.
      e7030995
  34. 07 Feb, 2002 2 commits
    • simonpj's avatar
      [project @ 2002-02-07 14:06:00 by simonpj] · ad552fe2
      simonpj authored
      -------------------------------------------
      	Improve the "stragely-kinded tyvar" problem
      	-------------------------------------------
      
      When the type checker finds a type variable with no binding,
      which means it can be instantiated with an arbitrary type, it
      usually instantiates it to Void.  Eg.
      
      	length []
      ===>
      	length Void (Nil Void)
      
      But in really obscure programs, the type variable might have
      a kind other than *, so we need to invent a suitably-kinded type.
      
      This commit uses
      	Void for kind *
      	List for kind *->*
      	Tuple for kind *->...*->*
      
      which deals with most cases.  (Previously, it only dealt with
      kind *.)
      
      In the other cases, it just makes up a TyCon with a suitable
      kind.  If this gets into an interface file, anyone reading that
      file won't understand it.  This is fixable (by making the client
      of the interface file make up a TyCon too) but it is tiresome and
      never happens, so I am leaving it.
      
      Most of the added lines are comments.
      ad552fe2
    • simonpj's avatar
      [project @ 2002-02-07 12:51:34 by simonpj] · 20f50b2a
      simonpj authored
      ----------------------------------------------------
      	Make TcType.match and TcUnify.uUnboundVar kind-aware
      	----------------------------------------------------
      
      George Russel had apparently-overlapping (ha) instance decls like
      
      	instance .. => C (a b) where
      	instance .. => C (x y) where
      
      But the a,b and x,y were different kinds!  Turned out that TcType.unify
      was kind-aware (so we didn't report a duplicate instance decl, but TcType.match
      was not (so we simply selected the wrong one, and got a mis-kinded constraint
      popping up from the ".."  part.  Very exciting to track down.
      
      I also make the ordinary unification kind-aware in the same way.  It's
      quite legitimate to attempt to unify, say,
      	(a b)    with     (c d)
      but the unification should fail if a's kind differs from c's.
      (There was a kind of debug warning before, but it's actually not an error
      in the compiler... so it should just make unification fail gracefully.)
      20f50b2a
  35. 06 Feb, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-02-06 15:54:23 by simonpj] · 979947f5
      simonpj authored
      Eliminate all vestiages of UsageTy, in preparation for
      	Keith's new version.  Hurrah!
      
      	Keith: LBVarInfo and usOnce,usMany are still there,
      	because I know you have eliminated LBVarInfo, and I didn't
      	want to cause unnecessary conflicts.
      979947f5
  36. 04 Feb, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-02-04 11:59:55 by simonpj] · 18dbe364
      simonpj authored
      -----------------------------
      	Improve type validity checking
      	-----------------------------
      
      Two main effects here
      
      a) Type synonyms can be unboxed tuples
      	tupe T = (# Int, Int #)
      
      	f :: Int -> T
      
      b) Hoisting works for implicit parameters
      
      	f :: Int -> (?x::Int) => Int
      18dbe364