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authorDavid Terei <davidterei@gmail.com>2011-07-20 11:09:03 -0700
committerDavid Terei <davidterei@gmail.com>2011-07-20 11:26:35 -0700
commit16514f272fb42af6e9c7674a9bd6c9dce369231f (patch)
treee4f332b45fe65e2a7a2451be5674f887b42bf199 /testsuite/tests/typecheck/should_run/tcrun030.hs
parentebd422aed41048476aa61dd4c520d43becd78682 (diff)
downloadhaskell-16514f272fb42af6e9c7674a9bd6c9dce369231f.tar.gz
Move tests from tests/ghc-regress/* to just tests/*
Diffstat (limited to 'testsuite/tests/typecheck/should_run/tcrun030.hs')
-rw-r--r--testsuite/tests/typecheck/should_run/tcrun030.hs20
1 files changed, 20 insertions, 0 deletions
diff --git a/testsuite/tests/typecheck/should_run/tcrun030.hs b/testsuite/tests/typecheck/should_run/tcrun030.hs
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+++ b/testsuite/tests/typecheck/should_run/tcrun030.hs
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+{-# LANGUAGE UndecidableInstances #-}
+
+-- Test recursive dictionaries
+
+module Main where
+
+data D r = ZeroD | SuccD (r (D r));
+
+instance (Eq (r (D r))) => Eq (D r) where
+ ZeroD == ZeroD = True
+ (SuccD a) == (SuccD b) = a == b
+ _ == _ = False;
+
+equalDC :: D [] -> D [] -> Bool;
+equalDC = (==);
+
+foo :: D []
+foo = SuccD [SuccD [ZeroD], ZeroD]
+
+main = print (foo == foo)