And also, prepare for correct lowering of lifetime. We still don't handle most lifetimes correctly, but a bit more of the foundation to lifetime elision is now implemented.
Also known as E0747 and E0107.
And by the way, rewrite how we lower generic arguments and deduplicate it between paths and method calls. The new version is taken almost straight from rustc.
This commit also changes the binders of `generic_defaults()`, to only include the binders of the arguments up to (and not including) the current argument. This make it easier to handle it in the rewritten lowering of generic args. It's also how rustc does it.
Now that they're const it's no longer needed.
Nothing manual was performed: only a regexp search of `sym::([\w][\w\d]*)\.clone\(\)` and replace by `sym::$1`.
And make more queries non-interned.
Also flip the default for queries, now the default is to not intern and to intern a query you need to say `invoke_interned`.
The tiny bug was that `FnFlags::DEPRECTAED_SAFE_2024` and `FnFlags::RUSTC_ALLOW_INCOHERENT_IMPLS` were assigned the same value.
The catastrophic effect was that every function marked as `#[rustc_allow_incoherent_impl]` was considered safe-deprecated for edition 2024, which caused it to be considered unsafe to call when called from edition 2024. And that includes `<[_]>::into_vec()`, which is called by the `vec![]` macro. So, catastrophic effect.
This innocent-looking bug probably arose from the item tree rewrite. No review would've catch that!
This refactors how we deal with items in hir-def lowering.
- It now lowers all of them through an "ExpressionStore" (kind of a misnomer as this point) as their so called *Signatures.
- We now uniformly lower type AST into TypeRefs before type inference.
- Likewise, this moves macro expansion out of type inference, resulting in a single place where we do non-defmap macro expansion.
- Finally, this PR removes a lot of information from ItemTree, making the DefMap a lot less likely to be recomputed and have it only depend on actual early name resolution related information (not 100% true, we still have ADT fields in there but thats a follow up removal).
Specifically, #18744 was the PR that was supposed to fix the old bug, but it fixed it incorrectly (and didn't add a test!) The underlying reason was that we marked metavariables in expansions as joint if they were joint in the macro call, which is incorrect.
This wrong fix causes other bug, #19497, which this PR fixes by removing the old (incorrect) fix.
