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)
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
- pprTrace "SpecConstr" (pprCoreRule (ppr fn) rule) $
returnUs (rule, (spec_id, spec_rhs))
\end{code}