Unable to build helix-lsp on latest nightly: reached the type-length limit while instantiating helix_parsec::or

[RossSmyth]

The latest nightly (154fdac39 2024-07-07) no longer is able to compile Helix. This is still being triaged upstream but I am filing this issue to track it here and ensure Helix users are aware of it.

These are the lines that fail:

helix/helix-lsp/src/snippet.rs

Lines 429 to 436 in 0c8d51e

	let parser = choice!(
	tabstop(),
	placeholder(),
	choice(),
	variable(),
	map("$", |_| SnippetElement::Text("$".into())),
	map(text(escape_chars, term_chars), SnippetElement::Text),
	);

With the error:

error: reached the type-length limit while instantiating `helix_parsec::or::<'_, {closure@helix_parsec::map<'_, (&str, {closure@helix_parsec::filter_map<'_, ..., ..., ...>::{closure#0}}, ..., ..., ...), ..., ...>::{closure#0}}, ..., ...>`
   --> helix-lsp\src\snippet.rs:429:26
    |
429 |               let parser = choice!(
    |  __________________________^
430 | |                 tabstop(),
431 | |                 placeholder(),
432 | |                 choice(),
...   |
435 | |                 map(text(escape_chars, term_chars), SnippetElement::Text),
436 | |             );
    | |_____________^
    |
    = help: consider adding a `#![type_length_limit="28949205"]` attribute to your crate
    = note: the full type name has been written to 'C:\Users\rsmyth\AppData\Local\helix\target\release\deps\helix_lsp-8d2cb44db19181ec.long-type.txt'
    = note: this error originates in the macro `choice` (in Nightly builds, run with -Z macro-backtrace for more info)

error: could not compile `helix-lsp` (lib) due to 1 previous error
warning: build failed, waiting for other jobs to finish...
error: failed to compile `helix-term v24.3.0 (C:\Users\rsmyth\AppData\Local\helix\helix-term)`, intermediate artifacts can be found at `C:\Users\rsmyth\AppData\Local\helix\target`.

rust-lang/rust#125507

[RossSmyth]

It may also be a good idea to consider moving away from the type-system recursive parser combinators that are currently used in the parsec crate as they are heavy on rustc

[RossSmyth]

Builds again in the latest nightly after rust-lang/rust#127670