fn check_parameters()

in starlark/src/syntax/validate.rs [178:228]
46 lines of code
10 McCabe index (conditional complexity)

fn check_parameters(parameters: &[AstParameter], codemap: &CodeMap) -> anyhow::Result<()> {
    let err = |span, msg| Err(Diagnostic::new(msg, span, codemap));

    // you can't repeat argument names
    let mut argset = HashSet::new();
    // You can't have more than one *args/*, **kwargs
    // **kwargs must be last
    // You can't have a required `x` after an optional `y=1`
    let mut seen_args = false;
    let mut seen_kwargs = false;
    let mut seen_optional = false;

    for arg in parameters.iter() {
        match &arg.node {
            Parameter::Normal(n, ..) => {
                if seen_kwargs || seen_optional {
                    return err(arg.span, ArgumentUseOrderError::PositionalThenNonPositional);
                }
                test_param_name(&mut argset, n, arg, codemap)?;
            }
            Parameter::WithDefaultValue(n, ..) => {
                if seen_kwargs {
                    return err(arg.span, ArgumentUseOrderError::DefaultParameterAfterStars);
                }
                seen_optional = true;
                test_param_name(&mut argset, n, arg, codemap)?;
            }
            Parameter::NoArgs => {
                if seen_args || seen_kwargs {
                    return err(arg.span, ArgumentUseOrderError::ArgsParameterAfterStars);
                }
                seen_args = true;
            }
            Parameter::Args(n, ..) => {
                if seen_args || seen_kwargs {
                    return err(arg.span, ArgumentUseOrderError::ArgsParameterAfterStars);
                }
                seen_args = true;
                test_param_name(&mut argset, n, arg, codemap)?;
            }
            Parameter::KwArgs(n, ..) => {
                if seen_kwargs {
                    return err(arg.span, ArgumentUseOrderError::MultipleKwargs);
                }
                seen_kwargs = true;
                test_param_name(&mut argset, n, arg, codemap)?;
            }
        }
    }
    Ok(())
}