[project @ 2001-05-09 13:46:29 by simonpj]

Fix bug in spec-constr rule generation [Sergei2]

diff --git a/ghc/compiler/specialise/SpecConstr.lhs b/ghc/compiler/specialise/SpecConstr.lhs
index dfea0cb..88d32f5 100644 (file)
--- a/ghc/compiler/specialise/SpecConstr.lhs
+++ b/ghc/compiler/specialise/SpecConstr.lhs
@@ -468,18 +468,17 @@ spec_one :: ScEnv
   Example
   
      In-scope: a, x::a   
-     f = /\b \y::[(a,b)] -> ....f (b,c) ((:) (a,(b,c)) v (h v))...
-         [c is presumably bound by the (...) part]
+     f = /\b \y::[(a,b)] -> ....f (b,c) ((:) (a,(b,c)) (x,v) (h w))...
+         [c::*, v::(b,c) are presumably bound by the (...) part]
   ==>
-     f_spec = /\ b c \ v::(a,(b,c)) -> 
-                 (...entire RHS of f...) (b,c) ((:) (a,(b,c)) v (h v))
+     f_spec = /\ b c \ v::(b,c) hw::[(a,(b,c))] ->
+                 (...entire RHS of f...) (b,c) ((:) (a,(b,c)) (x,v) hw)
   
-     RULE:  forall b c,
-                  y::[(a,(b,c))], 
-                  v::(a,(b,c)), 
-                  h::(a,(b,c))->[(a,(b,c))] .
+     RULE:  forall b::* c::*,          -- Note, *not* forall a, x
+                  v::(b,c),
+                  hw::[(a,(b,c))] .
   
-           f (b,c) ((:) (a,(b,c)) v (h v)) = f_spec b c v
+           f (b,c) ((:) (a,(b,c)) (x,v) hw) = f_spec b c v hw
 -}
 
 spec_one env fn rhs (pats, n)
@@ -491,14 +490,15 @@ spec_one env fn rhs (pats, n)
        pat_fvs      = varSetElems (exprsFreeVars pats)
        vars_to_bind = filter not_avail pat_fvs
        not_avail v  = not (v `elemVarEnv` scope env)
-               -- Put the type variables first just for tidiness
+               -- Put the type variables first; the type of a term
+               -- variable may mention a type variable
        (tvs, ids)   = partition isTyVar vars_to_bind
        bndrs        = tvs ++ ids
        
        rule_name = _PK_ ("SC:" ++ showSDoc (ppr fn <> int n))
        spec_rhs  = mkLams bndrs (mkApps rhs pats)
        spec_id   = mkUserLocal spec_occ spec_uniq (exprType spec_rhs) fn_loc
-       rule      = Rule rule_name pat_fvs pats (mkVarApps (Var spec_id) bndrs)
+       rule      = Rule rule_name bndrs pats (mkVarApps (Var spec_id) bndrs)
     in
     returnUs (rule, (spec_id, spec_rhs))
 \end{code}