Regression in 3.3.4 (reached the instantiation recursion limit)

[ordian]

toml_edit fails to compile with combine 3.3.4:

error: reached the recursion limit while instantiating `<parser::datetime::date_time<combine::easy::Stream<combine::stream::state::State<&str, combine::stream::state::SourcePosition>>> as combine::Parser>::parse_mode::<combine::parser::FirstMode>`

[Marwes]

It seems that 5257988 increased the function nesting just enough to bring toml_edit over the recursion limit for monomorphizing (which seems to be 64). Increasing it with #![recursion_limit = "87"] seems to enough to make it compile again whereas 61 is enough with combine 3.3.1. Since the function that hit the limit is so close already I don't think I can fix this in combine unfortunately (without reverting the bug fix).

[ordian]

Ok, if it can't be reverted, I'm going to close this issue.

[Marwes]

@ordian I opened an issue on rust-lang/rust to see why the limit is so low rust-lang/rust#51951 (compared to macro expansion)

[nikklassen]

I was also having this issue. I assume that the only solution is to convert a subset of the parsers to use Boxed parsers (given that the grammar I'm parsing can't change). Is that correct?

[Marwes]

@nikklassen You can bump the recursion limit by specifying #![recursion_limit = "256"] at your crate's root (default is 64 for this type of recursion).