Fix Type-Check for instance declarations with ambiguous funtion names

CHANGELOG.md

 Change log for curry-frontend
 =============================
 
+Version 1.0.4
+=============
+
+  * Fixed bug in type checking of instances
+
 Version 1.0.3
 =============
 
@@ -308,4 +313,3 @@ Version 0.3.0
   * All compiler warnings removed.
 
   * Fixed various implementation bugs (#9, #16, #19, #29, #289).
-

src/Checks/TypeCheck.hs

@@ -869,7 +869,11 @@ tcTopPDecl (i, ClassDecl p cx cls tv ds) = withLocalSigEnv $ do
 tcTopPDecl (i, InstanceDecl p cx qcls ty ds) = do
   tcEnv <- getTyConsEnv
   pty <- expandPoly $ QualTypeExpr NoSpanInfo cx ty
-  vpds' <- mapM (tcInstanceMethodPDecl qcls pty) vpds
+  mid <- getModuleIdent
+  let origCls = getOrigName mid qcls tcEnv
+      clsQual = head $ filter isQualified $ reverseLookupByOrigName origCls tcEnv
+      qQualCls = qualQualify (fromJust $ qidModule clsQual) qcls
+  vpds' <- mapM (tcInstanceMethodPDecl qQualCls pty) vpds
   return (i, InstanceDecl p cx qcls ty $ fromPDecls $ map untyped opds ++ vpds')
   where (vpds, opds) = partition (isValueDecl . snd) $ toPDecls ds
 tcTopPDecl _ = internalError "Checks.TypeCheck.tcTopDecl"