diff --git a/fco2/Parse.hs b/fco2/Parse.hs
index 36b23c9..95fc5f5 100644
--- a/fco2/Parse.hs
+++ b/fco2/Parse.hs
@@ -1386,6 +1386,10 @@ inputItem t
              sColons
              w <- variableOfType (makeArrayType A.UnknownDimension it)
              return $ A.InCounted m v w
+        A.Any ->
+          do m <- md
+             v <- variable
+             return $ A.InVariable m v
         _ ->
           do m <- md
              v <- variableOfType t
@@ -1462,6 +1466,11 @@ outputItem t
              sColons
              b <- expressionOfType (makeArrayType A.UnknownDimension it)
              return $ A.OutCounted m a b
+        A.Any ->
+          do m <- md
+             e <- expression
+             t <- typeOfExpression e
+             return $ A.OutExpression m e
         _ ->
           do m <- md
              e <- expressionOfType t
diff --git a/fco2/TODO b/fco2/TODO
index cd0986a..588df1e 100644
--- a/fco2/TODO
+++ b/fco2/TODO
@@ -47,6 +47,9 @@ calls have been removed, and so on.
 
 ## C backend
 
+Array outputs of dynamically-sized slices won't work (genBytesInType needs to
+know the size of the array it's dealing with).
+
 We could have genSpec generate {} around specs if it's not immediately inside
 another spec (which'd require some extra boolean arguments to find out).