Commit 7a5920b3 authored by simonpj's avatar simonpj
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[project @ 2001-10-17 13:16:03 by simonpj]

  	Desugar bindings into Rec groups more often
		[Part 2]


	  [I forgot the unlifted case.]

  In rather obscure cases (involving functional dependencies)
  it is possible to get an AbsBinds [] [] (no tyvars, no dicts)
  which nevertheless has some "dictionary bindings".  These
  come out of the typechecker in non-dependency order, so we
  need to Rec them just in case.

  It turns out to be a bit awkward.  The smallest fix is
  to make dsLet always make a Rec; brutal but correct.
parent 3b9d7c81
......@@ -85,23 +85,38 @@ dsLet (ThenBinds b1 b2) body
dsLet b1 body'
-- Special case for bindings which bind unlifted variables
-- We need to do a case right away, rather than building
-- a tuple and doing selections.
-- Silently ignore INLINE pragmas...
dsLet (MonoBind (AbsBinds [] [] binder_triples inlines
(PatMonoBind pat grhss loc)) sigs is_rec) body
| or [isUnLiftedType (idType g) | (_, g, l) <- binder_triples]
dsLet (MonoBind (AbsBinds [] [] exports inlines binds) sigs is_rec) body
| or [isUnLiftedType (idType g) | (_, g, l) <- exports]
= ASSERT (case is_rec of {NonRecursive -> True; other -> False})
putSrcLocDs loc $
dsGuarded grhss `thenDs` \ rhs ->
body' = foldr bind body binder_triples
bind (tyvars, g, l) body = ASSERT( null tyvars )
bindNonRec g (Var l) body
mkErrorAppDs iRREFUT_PAT_ERROR_ID result_ty (showSDoc (ppr pat))
`thenDs` \ error_expr ->
matchSimply rhs PatBindRhs pat body' error_expr
-- Unlifted bindings are always non-recursive
-- and are always a Fun or Pat monobind
-- ToDo: in some bizarre case it's conceivable that there
-- could be dict binds in the 'binds'. (See the notes
-- below. Then pattern-match would fail. Urk.)
case binds of
FunMonoBind fun _ matches loc
-> putSrcLocDs loc $
matchWrapper (FunRhs fun) matches `thenDs` \ (args, rhs) ->
ASSERT( null args ) -- Functions aren't lifted
returnDs (bindNonRec fun rhs body_w_exports)
PatMonoBind pat grhss loc
-> putSrcLocDs loc $
dsGuarded grhss `thenDs` \ rhs ->
mk_error_app pat `thenDs` \ error_expr ->
matchSimply rhs PatBindRhs pat body_w_exports error_expr
result_ty = exprType body
body_w_exports = foldr bind_export body exports
bind_export (tvs, g, l) body = ASSERT( null tvs )
bindNonRec g (Var l) body
mk_error_app pat = mkErrorAppDs iRREFUT_PAT_ERROR_ID
(exprType body)
(showSDoc (ppr pat))
-- Ordinary case for bindings
dsLet (MonoBind binds sigs is_rec) body
......@@ -114,7 +129,10 @@ dsLet (MonoBind binds sigs is_rec) body
-- but which does have dictionary bindings.
-- See notes with TcSimplify.inferLoop [NO TYVARS]
-- It turned out that wrapping a Rec here was the easiest solution
-- NB The previous case dealt with unlifted bindings, so we
-- only have to deal with lifted ones now; so Rec is ok
%* *
......@@ -625,6 +643,3 @@ dsLit (HsRat r ty)
(tycon, [i_ty]) -> ASSERT(isIntegerTy i_ty && tycon `hasKey` ratioTyConKey)
(head (tyConDataCons tycon), i_ty)
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