Unable to use ByteString literals in on-chain code

[anton-k]

Area

[*] Plutus Foundation Related to the GHC plugin, Haskell-to-Plutus compiler, on-chain code

Summary

I need to append some constant marker to a token name.
But when I use in on-chain code constant string literals that are meant to be ByteString \bs -> "a" <> bs
I get an error of PLC plugin:

Core to PLC plugin: E043:Error: Reference to a name which is not a local, a builtin, 
or an external INLINABLE function: Variable GHC.List.$wlenAcc
           No unfolding

Steps to reproduce

It happens when we use string literals for ByteString in on-chain code.

Expected behavior

I would like to append some data to the ByteString in on-chain code.

System info:

• OS: Manjaro, Linux
• Plutus version or commit hash: 62be7a2

[ghost]

Thanks for the issue!

Unfortunately, ByteString literals are not supported at all at the moment.

I may suggest to pass constants as a part of datum (fields in ADT) or as arguments for now.

[kevinhammond]

Yes, I hit this when trying to prepare the testnet exercises. I worked around it by using an integer literal. I believe you could also use strings in datums and redeemers. The problem I hit is partly down to staging in the Plutus compiler (byte strings have some dynamic component - they are not just calculated as compile-time constants).

[longngn]

Hi @ak3n, I know that your team is busy and thank you for all the hard work to put Plutus closer to the production launch. I would like to ask if this issue has a high priority on the roadmap? I believe that having this issue fixed would be a great improvement to the developer experience.

[ghost]

Hi @longngn, yeah, I'm working on it at the moment, #3327 is active and quite close to the merge. I hope it will land the master this week.

[anton-k]

Thanks for that!