1 files changed, 36 insertions, 0 deletions
diff --git a/testsuite/tests/lib/should_run/dynamic004.hs b/testsuite/tests/lib/should_run/dynamic004.hs
new file mode 100644
index 0000000000..e6b7a82bfd
--- /dev/null
+++ b/testsuite/tests/lib/should_run/dynamic004.hs
@@ -0,0 +1,36 @@
+module Main where
+
+import Data.Typeable
+import Data.Typeable.Internal
+import GHC.Fingerprint
+import Text.Printf
+
+f :: Typeable a => Int -> a -> [TypeRep]
+f 0 a = []
+f n a = typeOf a : f (n-1) [a]
+
+-- pointwise compare 1000x1001 TypeReps, there should be exactly 1000 equalities
+-- (can be used as a benchmark)
+main = print $ length [ t1 | t1 <- f 1000 (), t2 <- f 1001 (), t1 == t2 ]
+
+{-
+ DEBUGGING code to help find bugs in the TypeRep implementation when
+ this test fails:
+
+ where
+   g (x:xs) (y:ys)
+     | x == y = g xs ys
+     | otherwise = do
+         print x
+         case x of
+           TypeRep f1 (TyCon f2 _ _ _) [TypeRep f3 _ _] ->
+              printf "f1: %s\nf2: %s\nf3: %s\n" (show_fp f1) (show_fp f2) (show_fp f3)
+         case y of
+           TypeRep f1 (TyCon f2 _ _ _) [TypeRep f3 _ _] ->
+              printf "f1: %s\nf2: %s\nf3: %s\n" (show_fp f1) (show_fp f2) (show_fp f3)
+   g _ _ = return ()
+
+   show_fp :: Fingerprint -> String
+   show_fp (Fingerprint h l) =
+       printf "%x %x" h l
+-}