[Compiler Error] vyper.exceptions.TypeCheckFailure: pack_arguments did not return a value

[vasa-develop]

Version Information

• vyper Version (output of vyper --version): 0.2.4+commit.7949850
• OS: Ubuntu
• Python Version (output of python --version): Python 3.7.6
• Environment (output of pip freeze): https://pastebin.com/WA2mNEV4

What's your issue about?

Contract File

# @version >=0.2.4 <0.3.0

struct Pokemon:
    name: String[32]
    dna: uint256
    HP: uint256
    matches: uint256
    wins: uint256


trainerToPokemon: HashMap[address, HashMap[uint256, Pokemon]]

WILD_POKEMON: constant(address) = 0xB8c77482e45F1F44dE1745F52C74426C631bDD52

interface WildPokemons:
    def battle(pokemon: Pokemon) -> (bool, String[32], uint256, uint256): nonpayable

@external
def test(pokemonIndex: uint256):
    battleResult: bool = empty(bool)
    newPokemonName: String[32] = empty(String[32])
    newPokemonDNA: uint256 = empty(uint256)
    newPokemonHP: uint256 = empty(uint256)

    battleResult, newPokemonName, newPokemonDNA, newPokemonHP = WildPokemons(WILD_POKEMON).battle(self.trainerToPokemon[msg.sender][pokemonIndex])

Encountered Error

[Compiler Error] vyper.exceptions.TypeCheckFailure: pack_arguments did not return a value This is an unhandled internal compiler error.

How can it be fixed?

How can I fix this compiler error?

[charles-cooper]

fixed in #2447