[Agda] Codata error

[Sergei Meshveliani]

Can anybody, please, tell how to fix the following program?

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open import Foreign.Haskell
open import IO.Primitive
open import Codata.Musical.Costring using (toCostring)

main : IO Unit
main = putStrLn (toCostring "abc")
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Development Agda of December 23, 2018
reports of
        Termination check failure in  Codata.Musical.Conat.

Is this a bug in Agda? 
Do I misuse the Development Standard library of December 23, 2018 ?

Thanks,

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Sergei