From 4bccb87e864615c08f449430e3c1a48b7a50944e Mon Sep 17 00:00:00 2001
From: Kai-Oliver Prott <kai.prott@hotmail.de>
Date: Mon, 15 Apr 2019 15:47:10 +0200
Subject: [PATCH] Fix bug when deriving instances of Bounded type class

---
 CHANGELOG.md                  | 1 +
 src/Checks/InstanceCheck.hs   | 2 +-
 src/Transformations/Derive.hs | 4 ++--
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 69ead6d3..3013945e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ Version 1.0.4
 =============
 
   * Fixed bug in type checking of instances
+  * Fixed bugs in deriving of `Bounded` instances.
 
 Version 1.0.3
 =============
diff --git a/src/Checks/InstanceCheck.hs b/src/Checks/InstanceCheck.hs
index 957411ec..bad59d26 100644
--- a/src/Checks/InstanceCheck.hs
+++ b/src/Checks/InstanceCheck.hs
@@ -196,7 +196,7 @@ bindDerivedInstance clsEnv p tc pty tys cls = do
                                     , (fromEnumId, 1), (enumFromId, 1)
                                     , (enumFromThenId, 2)
                                     ]
-              | cls == qBoundedId = [(maxBoundId, 1), (minBoundId, 1)]
+              | cls == qBoundedId = [(maxBoundId, 0), (minBoundId, 0)]
               | cls == qReadId    = [(readsPrecId, 2)]
               | cls == qShowId    = [(showsPrecId, 2)]
               | otherwise         =
diff --git a/src/Transformations/Derive.hs b/src/Transformations/Derive.hs
index 8b73c40c..b6f0d834 100644
--- a/src/Transformations/Derive.hs
+++ b/src/Transformations/Derive.hs
@@ -274,8 +274,8 @@ enumFromThenExpr v1 v2 c1 c2 =
 
 deriveBoundedMethods :: Type -> [ConstrInfo] -> PredSet -> DVM [Decl PredType]
 deriveBoundedMethods ty cis ps = sequence
-  [ deriveMaxOrMinBound qMaxBoundId ty (head cis) ps
-  , deriveMaxOrMinBound qMinBoundId ty (last cis) ps
+  [ deriveMaxOrMinBound qMinBoundId ty (head cis) ps
+  , deriveMaxOrMinBound qMaxBoundId ty (last cis) ps
   ]
 
 deriveMaxOrMinBound :: QualIdent -> Type -> ConstrInfo -> PredSet
-- 
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