1. 11 Mar, 2005 1 commit
    • simonpj's avatar
      [project @ 2005-03-11 10:36:35 by simonpj] · 75649bcc
      simonpj authored
      ----------------------------------
       	Fix a "class used as a type" crash
      	----------------------------------
      
      	Merge to STABLE
      
      Thanks to Shae for finding this one.  tcfail134 tests.
      75649bcc
  2. 27 Jan, 2005 2 commits
    • simonpj's avatar
      [project @ 2005-01-27 11:51:56 by simonpj] · 56f5bc18
      simonpj authored
      Import trimming
      56f5bc18
    • simonpj's avatar
      [project @ 2005-01-27 10:44:00 by simonpj] · 508a505e
      simonpj authored
      --------------------------------------------
                Replace hi-boot files with hs-boot files
        	--------------------------------------------
      
      This major commit completely re-organises the way that recursive modules
      are dealt with.
      
        * It should have NO EFFECT if you do not use recursive modules
      
        * It is a BREAKING CHANGE if you do
      
      ====== Warning: .hi-file format has changed, so if you are
      ======		updating into an existing HEAD build, you'll
      ======		need to make clean and re-make
      
      
      The details:  [documentation still to be done]
      
      * Recursive loops are now broken with Foo.hs-boot (or Foo.lhs-boot),
        not Foo.hi-boot
      
      * An hs-boot files is a proper source file.  It is compiled just like
        a regular Haskell source file:
      	ghc Foo.hs		generates Foo.hi, Foo.o
      	ghc Foo.hs-boot		generates Foo.hi-boot, Foo.o-boot
      
      * hs-boot files are precisely a subset of Haskell. In particular:
      	- they have the same import, export, and scoping rules
      	- errors (such as kind errors) in hs-boot files are checked
        You do *not* need to mention the "original" name of something in
        an hs-boot file, any more than you do in any other Haskell module.
      
      * The Foo.hi-boot file generated by compiling Foo.hs-boot is a machine-
        generated interface file, in precisely the same format as Foo.hi
      
      * When compiling Foo.hs, its exports are checked for compatibility with
        Foo.hi-boot (previously generated by compiling Foo.hs-boot)
      
      * The dependency analyser (ghc -M) knows about Foo.hs-boot files, and
        generates appropriate dependencies.  For regular source files it
        generates
      	Foo.o : Foo.hs
      	Foo.o : Baz.hi		-- Foo.hs imports Baz
      	Foo.o : Bog.hi-boot	-- Foo.hs source-imports Bog
      
        For a hs-boot file it generates similar dependencies
      	Bog.o-boot : Bog.hs-boot
      	Bog.o-boot : Nib.hi	-- Bog.hs-boto imports Nib
      
      * ghc -M is also enhanced to use the compilation manager dependency
        chasing, so that
      	ghc -M Main
        will usually do the job.  No need to enumerate all the source files.
      
      * The -c flag is no longer a "compiler mode". It simply means "omit the
        link step", and synonymous with -no-link.
      508a505e
  3. 26 Jan, 2005 1 commit
    • simonpj's avatar
      [project @ 2005-01-26 16:10:02 by simonpj] · 8254dcf1
      simonpj authored
      -----------------------
      	Fixup to hoistForAllTys
      	-----------------------
      
      * hoistForAllTys moves from TcHsType to TcType
      
      hoistForAllTys was being too vigorous and breaking up type synonyms,
      even when it was entirely unnecessary to do so.
      
      Not only does this make error messsages less good, but it's actually
      wrong for Haskell 98, because we are meant to report under-applied
      type synonyms, and that check doesn't happen until after hoistForAllTys.
      This led to a very obscure bug, immortalised as tcfail129.
      8254dcf1
  4. 24 Dec, 2004 1 commit
    • simonpj's avatar
      [project @ 2004-12-24 11:02:39 by simonpj] · 0ee11df0
      simonpj authored
      Further wibbles to the scoped-tyvar story.
      
      This commit tidies up the ATyVar in TcTyThing, making it
      	ATyVar Name Type
      instead of the previous misleading
      	ATyVar TyVar Type
      
      But the main thing is that we must take care with definitions
      like this:
      
      	type T a = forall b. b -> (a,b)
      
      	f :: forall c. T c
      	f = ...
      
      Here, we want only 'c' to scope over the RHS of f.  The renamer ensures
      that... but we must also take care that we freshly instantiate the 
      expanded type signature (forall c b. b -> (c,b)) before checking f's RHS,
      so that we don't get false sharing between uses of T.
      0ee11df0
  5. 22 Dec, 2004 1 commit
    • simonpj's avatar
      [project @ 2004-12-22 16:58:34 by simonpj] · 20e39e0e
      simonpj authored
      ----------------------------------------
      	     Add more scoped type variables
      	----------------------------------------
      
      Now the top-level forall'd variables of a type signature scope
      over the right hand side of that function.
      
      	f :: a -> a
      	f x = ....
      
      The type variable 'a' is in scope in the RHS, and in f's patterns.
      
      It's implied by -fglasgow-exts, but can also be switched off independently
      using -fscoped-type-variables (and the -fno variant)
      20e39e0e
  6. 21 Dec, 2004 1 commit
    • simonpj's avatar
      [project @ 2004-12-21 12:22:22 by simonpj] · 79a8b87c
      simonpj authored
      ---------------------------------
           Improve handling of lexically scoped type variables
      	---------------------------------
      
      If we have
      
      	f :: T a -> a
      	f (x :: T b) = ...
      
      then the lexically scoped variable 'b' should refer to the rigid
      type variable 'a', without any intervening wobbliness.  Previously
      the in-scope type variables were always mutable TyVars, which were
      instantatiated to point to the type they were bound to; but since
      the advent of GADTs the intervening mutable type variable is a bad
      thing.
      
      Hence
        * In the type environment, ATyVar now carries a type
        * The call to refineTyVars in tc_pat on SigPatIn
          finds the types by matching
        * Then tcExtendTyVarEnv3 extends the type envt appropriately
      
      Rater a lot of huff and puff, but it's quite natural for ATyVar
      to contain a type.
      
      Various other small nomenclature changes along the way.
      79a8b87c
  7. 03 Dec, 2004 1 commit
  8. 30 Sep, 2004 1 commit
    • simonpj's avatar
      [project @ 2004-09-30 10:35:15 by simonpj] · 23f40f0e
      simonpj authored
      ------------------------------------
      	Add Generalised Algebraic Data Types
      	------------------------------------
      
      This rather big commit adds support for GADTs.  For example,
      
          data Term a where
       	  Lit :: Int -> Term Int
      	  App :: Term (a->b) -> Term a -> Term b
      	  If  :: Term Bool -> Term a -> Term a
      	  ..etc..
      
          eval :: Term a -> a
          eval (Lit i) = i
          eval (App a b) = eval a (eval b)
          eval (If p q r) | eval p    = eval q
          		    | otherwise = eval r
      
      
      Lots and lots of of related changes throughout the compiler to make
      this fit nicely.
      
      One important change, only loosely related to GADTs, is that skolem
      constants in the typechecker are genuinely immutable and constant, so
      we often get better error messages from the type checker.  See
      TcType.TcTyVarDetails.
      
      There's a new module types/Unify.lhs, which has purely-functional
      unification and matching for Type. This is used both in the typechecker
      (for type refinement of GADTs) and in Core Lint (also for type refinement).
      23f40f0e
  9. 06 Apr, 2004 1 commit
  10. 05 Apr, 2004 1 commit
  11. 02 Apr, 2004 1 commit
    • simonpj's avatar
      [project @ 2004-04-02 16:46:57 by simonpj] · 40888e1d
      simonpj authored
      Extend the "newtype deriving" feature a little bit more
      (at the request of Wolfgang Jeltsch)
      
      Here's the example:
          class C a b
          instance C [a] Char
          newtype T = T Char deriving( C [a] )
      
      Perfectly sensible, and no reason it should not work.
      Fixing this required me to generalise the abstract syntax of
      a 'deriving' item, hence the non-local effects.
      40888e1d
  12. 12 Jan, 2004 1 commit
  13. 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
  14. 16 Dec, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-12-16 16:24:55 by simonpj] · cb2be98a
      simonpj authored
      --------------------
      	Towards type splices
      	--------------------
      
      Starts the move to supporting type splices, by making
      HsExpr.HsSplice a separate type of its own, and adding
      HsSpliceTy constructor to HsType.
      cb2be98a
  15. 10 Dec, 2003 1 commit
    • simonmar's avatar
      [project @ 2003-12-10 14:15:16 by simonmar] · 55042138
      simonmar authored
      Add accurate source location annotations to HsSyn
      -------------------------------------------------
      
      Every syntactic entity in HsSyn is now annotated with a SrcSpan, which
      details the exact beginning and end points of that entity in the
      original source file.  All honest compilers should do this, and it was
      about time GHC did the right thing.
      
      The most obvious benefit is that we now have much more accurate error
      messages; when running GHC inside emacs for example, the cursor will
      jump to the exact location of an error, not just a line somewhere
      nearby.  We haven't put a huge amount of effort into making sure all
      the error messages are accurate yet, so there could be some tweaking
      still needed, although the majority of messages I've seen have been
      spot-on.
      
      Error messages now contain a column number in addition to the line
      number, eg.
      
         read001.hs:25:10: Variable not in scope: `+#'
      
      To get the full text span info, use the new option -ferror-spans.  eg.
      
         read001.hs:25:10-11: Variable not in scope: `+#'
      
      I'm not sure whether we should do this by default.  Emacs won't
      understand the new error format, for one thing.
      
      In a more elaborate editor setting (eg. Visual Studio), we can arrange
      to actually highlight the subexpression containing an error.  Eventually
      this information will be used so we can find elements in the abstract
      syntax corresponding to text locations, for performing high-level editor
      functions (eg. "tell me the type of this expression I just highlighted").
      
      Performance of the compiler doesn't seem to be adversely affected.
      Parsing is still quicker than in 6.0.1, for example.
      
      Implementation:
      
      This was an excrutiatingly painful change to make: both Simon P.J. and
      myself have been working on it for the last three weeks or so.  The
      basic changes are:
      
       - a new datatype SrcSpan, which represents a beginning and end position
         in a source file.
      
       - To reduce the pain as much as possible, we also defined:
      
            data Located e = L SrcSpan e
      
       - Every datatype in HsSyn has an equivalent Located version.  eg.
      
            type LHsExpr id = Located (HsExpr id)
      
         and pretty much everywhere we used to use HsExpr we now use
         LHsExpr.  Believe me, we thought about this long and hard, and
         all the other options were worse :-)
      
      
      Additional changes/cleanups we made at the same time:
      
        - The abstract syntax for bindings is now less arcane.  MonoBinds
          and HsBinds with their built-in list constructors have gone away,
          replaced by HsBindGroup and HsBind (see HsSyn/HsBinds.lhs).
      
        - The various HsSyn type synonyms have now gone away (eg. RdrNameHsExpr,
          RenamedHsExpr, and TypecheckedHsExpr are now HsExpr RdrName,
          HsExpr Name, and HsExpr Id respectively).
      
        - Utilities over HsSyn are now collected in a new module HsUtils.
          More stuff still needs to be moved in here.
      
        - MachChar now has a real Char instead of an Int.  All GHC versions that
          can compile GHC now support 32-bit Chars, so this was a simplification.
      55042138
  16. 06 Nov, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-11-06 17:09:50 by simonpj] · 1f5e5580
      simonpj authored
      ------------------------------------
      	Major increment for Template Haskell
      	------------------------------------
      
      1.  New abstract data type "Name" which appears where String used to be.
          E.g. 	data Exp = VarE Name | ...
      
      2.  New syntax 'x and ''T, for quoting Names.  It's rather like [| x |]
          and [t| T |] respectively, except that
      
      	a) it's non-monadic:  'x :: Name
      	b) you get a Name not an Exp or Type
      
      3.  reify is an ordinary function
      	reify :: Name -> Q Info
          New data type Info which tells what TH knows about Name
      
      4.  Local variables work properly.  So this works now (crashed before):
      	f x = $( [| x |] )
      
      5.  THSyntax is split up into three modules:
      
        Language.Haskell.TH		TH "clients" import this
      
        Language.Haskell.TH.THSyntax	data type declarations and internal stuff
      
        Language.Haskell.TH.THLib	Support library code (all re-exported
      				by TH), including smart constructors and
      				pretty printer
      
      6.  Error reporting and recovery are in (not yet well tested)
      
      	report :: Bool {- True <=> fatal -} -> String -> Q ()
      	recover :: Q a -> Q a -> Q a
      
      7.  Can find current module
      
      	currentModule :: Q String
      
      
      Much other cleaning up, needless to say.
      1f5e5580
  17. 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
  18. 27 Oct, 2003 1 commit
  19. 22 Oct, 2003 1 commit
  20. 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
  21. 13 Oct, 2003 1 commit
  22. 09 Oct, 2003 1 commit