MultipleCharsInSingleQuote runtime error not reported during compilation

[JRI98]

The following program builds without errors or warnings, but crashes at runtime with MultipleCharsInSingleQuote(@158-163):

app [main] { pf: platform "https://github.com/roc-lang/basic-cli/releases/download/0.16.0/O00IPk-Krg_diNS2dVWlI0ZQP794Vctxzv0ha96mK0E.tar.br" }

main = Task.ok '123'

[lukewilliamboswell]

The error message is provided by the platform. When roc hits a runtime error it call into roc_panic with a message. That message is generated from crates/compiler/problem/src/can.rs and currently uses the derived Debug impl.

pub fn runtime_message(self) -> String {
    use RuntimeError::*;

    match self {
        DegenerateBranch(region) => {
            format!(
                "Hit a branch pattern that does not bind all symbols its body needs, at {region:?}"
            )
        }
        err => format!("{err:?}"),
    }
}

We should probably provide a nicer error message string for roc_panic to print for end users.