It's better to read it as: "if we know these, then we're going to know these"
\begin{code}
-{-# OPTIONS_GHC -w #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
--- http://hackage.haskell.org/trac/ghc/wiki/WorkingConventions#Warnings
--- for details
-
module FunDeps (
Equation, pprEquation,
oclose, grow, improveOne,
\begin{code}
grow :: [PredType] -> TyVarSet -> TyVarSet
grow preds fixed_tvs
- | null preds = real_fixed_tvs
+ | null preds = fixed_tvs
| otherwise = loop real_fixed_tvs
where
-- Add the implicit parameters;
-- We usually act on an equation by instantiating the quantified type varaibles
-- to fresh type variables, and then calling the standard unifier.
+pprEquation :: Equation -> SDoc
pprEquation (qtvs, pairs)
= vcat [ptext SLIT("forall") <+> braces (pprWithCommas ppr (varSetElems qtvs)),
nest 2 (vcat [ ppr t1 <+> ptext SLIT(":=:") <+> ppr t2 | (t1,t2) <- pairs])]
-- combined (for error messages)
-- Just do improvement triggered by a single, distinguised predicate
-improveOne inst_env pred@(IParam ip ty, _) preds
+improveOne _inst_env pred@(IParam ip ty, _) preds
= [ ((emptyVarSet, [(ty,ty2)]), pred, p2)
| p2@(IParam ip2 ty2, _) <- preds
, ip==ip2
<+> ppr (getSrcLoc ispec))
]
-improveOne inst_env eq_pred preds
+improveOne _ _ _
= []