diff --git a/src/Libraries/Base1/CShow.bs b/src/Libraries/Base1/CShow.bs
index 2017ecb42..f0e8a59e9 100644
--- a/src/Libraries/Base1/CShow.bs
+++ b/src/Libraries/Base1/CShow.bs
@@ -73,6 +73,9 @@ instance (CShow a) => CShow' (Conc a) where
   cshow' (Conc x) = cshow x
   cshowP' (Conc x) = cshowP x
 
+instance CShow' (ConcPoly a) where
+  cshow' (ConcPoly _) = $format "<polymorphic value>"
+
 -- Note that below there are more specific instances for
 -- CShow' (Meta (MetaConsNamed ...)) and CShow' (Meta (MetaConsAnon ...))
 instance (CShow' a) => CShow' (Meta m a) where
diff --git a/testsuite/bsc.lib/CShow/TestCShow.bs b/testsuite/bsc.lib/CShow/TestCShow.bs
index 56d8340f6..ed5785cc7 100644
--- a/testsuite/bsc.lib/CShow/TestCShow.bs
+++ b/testsuite/bsc.lib/CShow/TestCShow.bs
@@ -19,6 +19,10 @@ struct Bar =
 data Baz a = Baz a a
   deriving (FShow)
 
+struct Qux =
+  x :: a -> a -- Higher rank
+  y :: Int 8
+
 sysTestCShow :: Module Empty
 sysTestCShow = module
   rules
@@ -35,4 +39,5 @@ sysTestCShow = module
       $display (cshow ((vec (Bar {x=42; foo=C}) (Bar {x=3; foo=B 2323})) :: Vector 2 Bar))
       $display (cshow ((Bar {x=42; foo=C}) :> (Bar {x=3; foo=B 2323}) :> ListN.nil))
       $display (cshow ("x", ((Left 123) :: Either (UInt 8) Bar, False)))
+      $display (cshow $ Qux {x = id; y = 42;})
       $finish
diff --git a/testsuite/bsc.lib/CShow/sysTestCShow.out.expected b/testsuite/bsc.lib/CShow/sysTestCShow.out.expected
index 2b57e7626..cf9ee03e5 100644
--- a/testsuite/bsc.lib/CShow/sysTestCShow.out.expected
+++ b/testsuite/bsc.lib/CShow/sysTestCShow.out.expected
@@ -10,3 +10,4 @@ Baz C (A  12 True (Bar {foo=D {a=0x22; b=C}; x= 42}))
 [Bar {foo=C; x= 42}, Bar {foo=B   2323; x=  3}]
 [Bar {foo=C; x= 42}, Bar {foo=B   2323; x=  3}]
 ("x", Left 123, False)
+Qux {x=<polymorphic value>; y=  42}