The StableOrd trait can be used to mark types as having a stable
sort order across compilation sessions. Collections that sort their
items in a stable way can safely implement HashStable by
hashing items in sort order.
Reorganizing `stacked_borrows` in anticipation of a different model
These commits reorganize all the code inside the former `stacked_borrows` module and extract the part that really is specific to Stacked Borrows inside the `borrow_tracker/stacked_borrows` submodule.
Everything not specific to SB is put in `borrow_tracker/mod.rs`.
This is so that the future Tree Borrows model can be later added as a second submodule and reuse all the contents of `borrow_tracker/mod.rs`.
This reorganization is accompanied by renamings, mostly from "stacked borrows" to "borrow tracking".
Add `type_ascribe!` macro as placeholder syntax for type ascription
This makes it still possible to test the internal semantics of type ascription even once the `:`-syntax is removed from the parser. The macro now gets used in a bunch of UI tests that test the semantics and not syntax of type ascription.
I might have forgotten a few tests but this should hopefully be most of them. The remaining ones will certainly be found once type ascription is removed from the parser altogether.
Part of #101728
Because the error message that emit out is from main error of parser
The information of enum variant disappears while parsing enum variant with error
We only check the syntax of expecting token, i.e, in case #103869
It will error it without telling the message that this error is from pasring enum variant.
Propagate the sub-error from parsing enum variant to the main error of parser by chaining it with map_err
Check the sub-error before emitting the main error of parser and attach it.
Fix#103869
rustc_ast_lowering: Stop lowering imports into multiple items
Lower them into a single item with multiple resolutions instead.
This also allows to remove additional `NodId`s and `DefId`s related to those additional items.
This avoids calling `early_lint_node` twice.
Note: one `early_lint_node` call had `!pre_expansion` for the second
argument and the other had `false`. The new single call just has
`!pre_expansion`. This results in a reduction of duplicate error
messages in some `ui-fulldeps` tests. The order of some `ui-fulldeps`
output also changes, but that doesn't matter.
