Exception: attempt to apply non-procedure 0

[bkomuves]

The following program crashes with scheme exception "attempt to apply non-procedure 0":

bug : Int -> Bool
bug a = 
  let f = \y => case y == a of { True => True ; False => False }
  in  or [ f y | y <- [0..10] ]

main : IO ()
main = printLn (bug 5)

I suspect this has to do with automatic delay/force insertion:

-- does not typecheck:
-- "Can't solve constraint between: Bool and Lazy Bool."
bug1 : Int -> Bool
bug1 a = 
  let f = \y => y == a
  in  or [ f y | y <- [0..10] ]

-- typechecks and works
bug2 : Int -> Bool
bug2 a = 
  let f = \y => y == a
  in  or [ delay (f y) | y <- [0..10] ]

-- also works
bug3 : Int -> Bool
bug3 a = 
  let f = \y => case y == a of { True => True ; False => False }
  in  or [ delay (f y) | y <- [0..10] ]

Steps to Reproduce

Load the very first snippet above into the REPL, and run :exec main.

I used the chez backend with Chez Scheme Version 9.5.7.

Expected Behavior

Prints True.

Observed Behavior

Crashes with

Exception: attempt to apply non-procedure 0