1 files changed, 17 insertions, 0 deletions
diff --git a/testsuite/tests/codeGen/should_fail/CheckBoundsReadWord8ArrayAsWord32.hs b/testsuite/tests/codeGen/should_fail/CheckBoundsReadWord8ArrayAsWord32.hs
new file mode 100644
index 0000000000..4bade0a101
--- /dev/null
+++ b/testsuite/tests/codeGen/should_fail/CheckBoundsReadWord8ArrayAsWord32.hs
@@ -0,0 +1,17 @@
+{-# LANGUAGE UnboxedTuples #-}
+{-# LANGUAGE MagicHash #-}
+
+module Main where
+
+import GHC.Exts
+import GHC.IO
+
+main :: IO ()
+main = do
+    IO $ \s0 ->
+      case newByteArray# 7# s0 of
+        (# s1, marr #) ->
+          case readWord8ArrayAsWord32# marr (-3#) s1 of
+            -- only the last byte of the desired word32 is in bounds
+            (# s2, _n #) -> (# s2, () #)
+