From e12e19567024ade8643918a88cc22a74d879afdb Mon Sep 17 00:00:00 2001
From: simonm <unknown>
Date: Thu, 4 Dec 1997 11:02:12 +0000
Subject: [PATCH] [project @ 1997-12-04 11:02:12 by simonm] fix huge bug in
extractHsTyVars - the list returned wasn't always a set (i.e. it could have
duplicates). This screwed up support for universal quantification in a
couple of places.
---
ghc/compiler/reader/RdrHsSyn.lhs | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/ghc/compiler/reader/RdrHsSyn.lhs b/ghc/compiler/reader/RdrHsSyn.lhs
index 053915204f13..22827fa4e1d8 100644
--- a/ghc/compiler/reader/RdrHsSyn.lhs
+++ b/ghc/compiler/reader/RdrHsSyn.lhs
@@ -127,16 +127,16 @@ extractHsTyVars ty
-- In (All a => a -> a) -> Int, there are no free tyvars
-- We just assume that we quantify over all type variables mentioned in the context.
- get (HsPreForAllTy ctxt ty) acc = filter (`notElem` locals) (get ty [])
- ++ acc
- where
- locals = foldr (get . snd) [] ctxt
+ get (HsPreForAllTy ctxt ty) acc =
+ foldr insert acc (filter (`notElem` locals) (get ty []))
+ where
+ locals = foldr (get . snd) [] ctxt
- get (HsForAllTy tvs ctxt ty) acc = (filter (`notElem` locals) $
+ get (HsForAllTy tvs ctxt ty) acc =
+ foldr insert acc (filter (`notElem` locals) $
foldr (get . snd) (get ty []) ctxt)
- ++ acc
- where
- locals = map getTyVarName tvs
+ where
+ locals = map getTyVarName tvs
insert (Qual _ _ _) acc = acc
insert (Unqual (TCOcc _)) acc = acc
--
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