1 files changed, 25 insertions, 0 deletions
diff --git a/testsuite/tests/typecheck/should_run/tcrun011.hs b/testsuite/tests/typecheck/should_run/tcrun011.hs
new file mode 100644
index 0000000000..5c6cab8ea0
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+++ b/testsuite/tests/typecheck/should_run/tcrun011.hs
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+{-# LANGUAGE ExistentialQuantification, FlexibleContexts,
+             MultiParamTypeClasses #-}
+
+-- !!! Existential data tyes
+-- Hugs didn't like this one
+
+module Main (main) where
+
+
+class MyClass a b where
+	foo :: a -> b -> Int
+
+data Special = forall b. (MyClass Int b)=> MkSpecial b
+data General a = forall b. (MyClass a b)=> MkGeneral b
+
+instance MyClass Int Bool where
+   foo x False = -x
+   foo x True  = x
+
+xs :: [General Int]
+xs = [MkGeneral True, MkGeneral False]
+
+main = print [foo (3::Int) x | MkGeneral x <- xs]
+	-- Without the (::Int) part we get an 
+	-- incomprehensible error message :-(