More Error(UnsupportedType) Feedback

[dan-fritchman]

Really helpful library, thanks so much for your work on it.

This issue is borne of dan-fritchman/Layout21#33, in which:

• I have a big tree of structs, with lots of fields, internal types, and external types along the way
• I pass the biggest top-most one to toml::to_string()
• What comes back is this:

failures:

---- tests::empty_lib_to_toml stdout ----
thread 'tests::empty_lib_to_toml' panicked at 'save failed: Error(UnsupportedType)', gds21/src/tests.rs:214:50
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Question: is there any good way to get more than UnsupportedType as feedback here?
(Set a setting, submit a PR to improve the error message, whatever.)

Thanks again!

[epage]

Yes, ideally we report more details to help people with this. However, a lot of things will be changing with #340 which I'm actively working on so I'd like to hold off on other changes until then.

[dan-fritchman]

Ok, cool, understand.

[dan-fritchman]

FWIW after an upgrade of toml (and some edits to our library), that error is now:

---- tests::golden_toml stdout ----
thread 'gds_serialization::tests::golden_toml' panicked at 'Could not save output file: values must be emitted before tables', 

I see there are handfuls of past discussions on this "ordering problem". My read is that they are all resolved, and should be handled inside the serializer? Do I have that wrong? In any case, is there a good reference for what "should work", e.g. do struct-fields need to be arranged in a particular order, etc.