Errors thrown from `config_argss` are eaten in `sampling`

Summary:

If an error is thrown withing rstan::config_argss, it is reported simply as 'error in specifying arguments; sampling not done', without reproducing the error produced in rstan::config_argss

Description:

I had a weird edge case where after calling sampling I got a puzzling error message: 'error in specifying arguments; sampling not done'. I was able to trace it to https://github.com/stan-dev/rstan/blob/71ab1409531c2c5e412635482fee545c77e2a070/rstan/rstan/R/stanmodel-class.R#L738 where it is triggerred by an error in rstan::config_argss, but the error itself is not shown. When investigating this, I modified something and no longer get this error, so I don't have a reproducible example, but in any case, I suspect the original error should be displayed to the user.

Current Output:

error in specifying arguments; sampling not done

Expected Output:

More specific error message
error in specifying arguments; sampling not done

RStan Version:

2.21, but present also in the current develop

R Version:

4.1.0

Operating System:

Windows 10

Read rstan/rstan/R/stanmodel-class.R around line 738, then trace how config_argss errors are handled during sampling. Confirm that the underlying error is retained or displayed before the generic sampling message, and verify the resulting output through the sampling error path.