1. 18 Aug, 2006 3 commits
    • simonpj@microsoft.com's avatar
      Better pretty-printing for TvSubst · 3287fb1d
      simonpj@microsoft.com authored
    • simonpj@microsoft.com's avatar
      Fall over more gracefully when there's a Template Haskell error · 7a59afce
      simonpj@microsoft.com authored
      For a long time, Template Haskell has fallen over in a very un-graceful
      way (i.e. panic) even when it encounters a programmer error.  In particular,
      when DsMeta converts HsSyn to TH syntax, it may find Haskell code that
      TH does not understand. This should be reported as a normal programmer
      error, not with a compiler panic!
      Originally the desugarer was supposed to never generate error
      messages, but this TH desugaring thing does make it do so.  And in
      fact, for other reasons, the desugarer now uses the TcRnIf monad, the
      common monad used by the renamer, typechecker, interface checker, and
      This patch completes the job, by 
       - allowing the desugarer to generate errors
       - re-plumbing the error handling to take account of this
       - making DsMeta use the new facilities to report error gracefully
      Quite a few lines of code are touched, but nothing deep is going on.
      Fixes Trac# 760.
    • simonpj@microsoft.com's avatar
  2. 17 Aug, 2006 6 commits
  3. 16 Aug, 2006 10 commits
    • simonpj@microsoft.com's avatar
      Add ad-hoc typing checks for tagToEnum# · c938c386
      simonpj@microsoft.com authored
      The problem with tagToEnum# is that it is not overloaded (in the
      Haskell sense) but you are only supposed to apply it to a TyCon
      that is an enumeration (isEnumerationTyCon).
      The Real Way to do this is to have some special kind of type constraint
      for the purpose, but that is wild overkill. So this patch adds a small
      rather ad-hoc check to TcExpr.instFun.  Crude, simple, but it works fine.
      Fixes Trac #786
      Test is tcfail164
    • simonpj@microsoft.com's avatar
      Get dead-ness right in knownCon · c55001c5
      simonpj@microsoft.com authored
    • simonpj@microsoft.com's avatar
      Tuning for argToPat · d66ea3ef
      simonpj@microsoft.com authored
      argToPat is a crucial function for SpecConstr, because it decides
      what patterns are worth specialising.  I was being much too gung-ho about
      constants.  This patch makes it much better.
    • simonpj@microsoft.com's avatar
      Re-factor mkAtomicArgs and completeNonRecX · ad0cc1df
      simonpj@microsoft.com authored
      This refactoring ensures that when mkAtomicArgs adds new bindings,
      it does so using completeNonRecX, which adds unfoldings etc.  More
      modular, and saves passes too.
      (This was important when getting rules to work right.  We want tob
      fire a rule as soon as possible, taking into account all inlinings,
      else a less-good rule applies.  That's what I found when doing 
      stream fusion anyway.)
      Regardless, this is an improvement.
    • simonpj@microsoft.com's avatar
      Another try at the continuation-swapping stuff · 0e98e80c
      simonpj@microsoft.com authored
      I have spent altogether too long on my attempt to avoid case-of-case
      in situations where it is a Bad Thing.  All the action is in the
      case for mkDupableAlt that handles cases with a single alternative.
      I've added rather extensive comments, and it finally seems to be working
      more or less right.  If you compile (say) GHC/Real.o you'll see quite a
      few case-of-cases remain (which didn't happen before), and they mostly look
      pretty sensible to me.
    • simonpj@microsoft.com's avatar
      Don't build unnecessary lets in knownCon · eba4dfc2
      simonpj@microsoft.com authored
      Faced with
      	case x of y { (a,b) -> rhs }
      where x is bound to (c,d), we were generating
      	let y = (c,d) in rhs
      and thenn hoping to get rid of the y binding by CSE or some such.  It's
      better simply not to build it in the first place, by generating
      	let y = x in rhs
      This patch does the job.
    • simonpj@microsoft.com's avatar
      Comments only · 08896210
      simonpj@microsoft.com authored
    • simonpj@microsoft.com's avatar
    • simonpj@microsoft.com's avatar
      Record constructor arg occs correctly (bug-fix) · 5338fea3
      simonpj@microsoft.com authored
      I was forgetting the non-pattern-matched type args of a constructor.
    • simonpj@microsoft.com's avatar
      Disable form-checking for rule LHSs · 1c36a2c0
      simonpj@microsoft.com authored
      Previously we checked the form of the arguments of a RULE lhs, to 
      ensure that they were simple applications. There was no good reason
      for that, save to prevent you writing LHSs that were unlikely to match.
      And Don Stewart found he wanted to do something we didn't allow (a section,
      I think).  So I have just disabled the check.
  4. 15 Aug, 2006 7 commits
    • simonpj@microsoft.com's avatar
      Allow class and instance decls in hs-boot files · dfcf8852
      simonpj@microsoft.com authored
      For some reason, in 6.5 the manual said you could put a class decl in
      an interface file, but not an instance decl; whereas the implementation
      was exactly the othe way round.
      This patch makes it possible to put *both* class and instance decls
      in an interface file. 
      I also did a bit of re-factoring; comparing the declarations in the
      hs-boot and hs file is now done by converting to IfaceSyn, because we
      have good comparison operations for IfaceSyn already implemented.
      This fixed a bug that previously let through an inconsistent declaration 
      of a data type.
      The remaining infelicity concerns "abstract" TyCons.  They are a bit
      of a hack anyway; and Classes are not handled in the same way.  Need
      to think about this, but I think it's probably ok as it stands.
    • simonpj@microsoft.com's avatar
      Reject derivable type classes with higher-rank methods · 4bcaad0c
      simonpj@microsoft.com authored
      Trac #864 suggested a derivable type class with a higher-rank method.
      In principle this is quite do-able, but in practice the mechanism works
      by generating source code and then doing type inference.  To make this work
      with higher-rank types would require impredicative polymorphism. And we 
      do have that, so it could probably be made to work by generating (source-level)
      type annotations.  But it's real work, so I'm settling for generating a
      decent error message rather than crashing.
    • simonpj@microsoft.com's avatar
      SpecConstr now specialises on constants and lambdas · c17dc70a
      simonpj@microsoft.com authored
      Roman inspired me to beef up SpecConstr to deal with
      a) constant arguments
      b) lambda arguments
      This is described in elaborate comments in the file:
       	Note [Specialising for constant parameters]
      	Note [Specialising for lambda parameters]
      I also took the opportunity to fix the usage analysis done by
      SpecConstr, which was only handling the top-level correctly.
      Now it does nesting too.
    • simonpj@microsoft.com's avatar
      Fix two bugs in rule-matching · 969baa16
      simonpj@microsoft.com authored
      These two typo-like bugs have been there for a long time!
        One concerns the selection of overlapping rules, 
        which was back to front
        The other was name-lining-up bug in the Case case of matching
      This patch also arranges to export matchN. 
        (Not a good name, but still!)
    • simonpj@microsoft.com's avatar
    • simonpj@microsoft.com's avatar
      Make UniqSM into a proper monad · 0d7c6cea
      simonpj@microsoft.com authored
    • simonpj@microsoft.com's avatar
  5. 14 Aug, 2006 5 commits
    • simonpj@microsoft.com's avatar
      Be more conservative about duplicating continuations · da107045
      simonpj@microsoft.com authored
      Roman found that GHC was duplicating continuations that arose (essentially)
      from uses of 'seq', or strict constructors.  This fixes the problem;
      see the comments mkDupableCont (the Select case with a single alternative).
      I'm a little concerned that this may also miss useful case-of-case
      tranformations, so I'd like to know if anyone finds that this patch
      makes performance worse.
      To make it a bit more gung-ho, one could check for all the binders
      being dead, before choosing this new, conservative alternative.
    • simonpj@microsoft.com's avatar
      Inline into tail-called constructor args · 098d99aa
      simonpj@microsoft.com authored
      	x = case y of { True -> (p,q); ... }
      The occurrence analyser was marking p,q as 'Many', because they args
      of a constructor in an RhsCtxt.  But actually they aren't in a RhsCtxt,
      and in this case it's better to inline.
    • simonpj@microsoft.com's avatar
      Improve exprIsCheap · 25ce05f7
      simonpj@microsoft.com authored
      exprIsCheap is meant to return True iff it's ok to push the expression
      inside a lambda.  But the previous version would return True of a nested
      construtor application like (1:2:3:[]), which isn't right.
      This patch re-factors the code somewhat, and fixes the bug.
    • bringert@cs.chalmers.se's avatar
    • simonpj@microsoft.com's avatar
      Improve error message in TcHsType · ef10d0a7
      simonpj@microsoft.com authored
      Fixes Trac #863.
      Test is tcfail162
  6. 11 Aug, 2006 9 commits