avoid generalization inside of aliases
The basic idea of this PR is that we don't generalize aliases when the instantiation could fail later on, either due to the *occurs check* or because of a universe error. We instead replace the whole alias with an inference variable and emit a nested `AliasRelate` goal. This `AliasRelate` then fully normalizes the alias before equating it with the inference variable, at which point the alias can be treated like any other rigid type.
We now treat aliases differently depending on whether they are *rigid* or not. To detect whether an alias is rigid we check whether `NormalizesTo` fails. While we already do so inside of `AliasRelate` anyways, also doing so when instantiating a query response would be both ugly/difficult and likely inefficient. To avoid that I change `instantiate_and_apply_query_response` to relate types completely structurally. This change generally removes a lot of annoying complexity, which is nice. It's implemented by adding a flag to `Equate` to change it to structurally handle aliases.
We currently always apply constraints from canonical queries right away. By providing all the necessary information to the canonical query, we can guarantee that instantiating the query response never fails, which further simplifies the implementation. This does add the invariant that *any information which could cause instantiating type variables to fail must also be available inside of the query*.
While it's acceptable for canonicalization to result in more ambiguity, we must not cause the solver to incompletely structurally relate aliases by erasing information. This means we have to be careful when merging universes during canonicalization. As we only generalize for type and const variables we have to make sure that anything nameable by such a type or const variable inside of the canonical query is also nameable outside of it. Because of this we both stop merging universes of existential variables when canonicalizing inputs, we put all uniquified regions into a higher universe which is not nameable by any type or const variable.
I will look into always replacing aliases with inference variables when generalizing in a later PR unless the alias references bound variables. This should both pretty much fix https://github.com/rust-lang/trait-system-refactor-initiative/issues/4. This may allow us to merge the universes of existential variables again by changing generalize to not consider their universe when deciding whether to generalize aliases. This requires some additional non-trivial changes to alias-relate, so I am leaving that as future work.
Fixes https://github.com/rust-lang/trait-system-refactor-initiative/issues/79. While it would be nice to decrement universe indices when existing a `forall`, that was surprisingly difficult and not necessary to fix this issue. I am really happy with the approach in this PR think it is the correct way forward to also fix the remaining cases of https://github.com/rust-lang/trait-system-refactor-initiative/issues/8.
Prioritise rustup sysroots over system ones
`get_path_for_executable` will now first check `$CARGO_HOME` before falling back to searching `$PATH`.
`rustup` is the recommended way to manage rust toolchains, therefore should be picked before the system toolchain.
Closes#16661
Document nvim 0.10 `inlay_hint`
It took me a few hours to figure out how to enable inlay type hints on Nvim 0.10 with `lspconfig`. `rustaceanvim` has already dropped support for them (https://github.com/mrcjkb/rustaceanvim/discussions/46#discussioncomment-7518669) and most other plugins, like `rust-tools`, are depreciated in favor of `rustaceanvim`.
This PR documents how to enable the inlay hints on Neovim 0.10 and later. I've tested this and changing the `on_attach` function is the only step that is required.
only checking whether nested goals hold means that we don't consider
their inference constraints. Given that we now emit `AliasRelate` when relating
aliases and infer vars, this previously resulted in an "unconstrained" inference var
in `coerce_unsized`.
tree borrows: add a test to sb_fails
This is something that happens in the wild (https://github.com/rust-lang/rust/issues/121626), so TB accepting this is good. Let's make sure we notice if this ever changes.
Fix more #121208 fallout (round 3)
#121208 converted lots of delayed bugs to bugs. Unsurprisingly, there were a few invalid conversion found via fuzzing.
r? `@lcnr`
Correctly handle if rustdoc JS script hash changed
It's something that annoyed me for quite some time: I have nightly docs open (for both std and compiler). And often, I don't look at the page for some days. Then when I come back to it, I make a search... except nothing happens. Took me a while to figure out that it was because the hash of one of the JS files we load for the search (either `search.js` or `search-index.js`) was updated in the meantime, preventing the search to be done. To go around it, I added to press `ENTER` to make the form submitted (which would reload the same page but with the correct hashes this time and the search being run).
r? `@notriddle`
Don't unnecessarily change `SIGPIPE` disposition in `unix_sigpipe` tests
In `auxiliary/sigpipe-utils.rs`, all we want to know is the current `SIGPIPE` disposition. We should not change it. So use `libc::sigaction` instead of `libc::signal`. That way we can also remove the code that restores it.
Part of https://github.com/rust-lang/rust/issues/97889.
Split Diagnostics for Uncommon Codepoints: Add Individual Identifier Types
This pull request further modifies the `uncommon_codepoints` lint, adding the individual identifier types of `Technical`, `Not_NFKC`, `Exclusion` and `Limited_Use` to the diagnostic message.
Example rendered diagnostic:
```
error: identifier contains a Unicode codepoint that is not used in normalized strings: 'ij'
--> $DIR/lint-uncommon-codepoints.rs:6:4
|
LL | fn dijkstra() {}
| ^^^^^^^
= note: this character is included in the Not_NFKC Unicode general security profile
```
Second step of #120228.
Allow tests to specify a `//@ filecheck-flags:` header
This allows individual codegen/assembly/mir-opt tests to pass extra flags to the LLVM `filecheck` tool as needed.
---
The original motivation was noticing that `tests/run-make/instrument-coverage` was very close to being an ordinary codegen test, except that it needs some extra logic to set up platform-specific variables to be passed into filecheck.
I then saw the comment in `verify_with_filecheck` indicating that a `filecheck-flags` header might be useful for other purposes as well.
Add `StructurallyRelateAliases` to allow instantiating infer vars with rigid aliases.
Change `instantiate_query_response` to be infallible in the new solver. This requires canonicalization to not hide any information used by the query, so weaken
universe compression. It also modifies `term_is_fully_unconstrained` to allow
region inference variables in a higher universe.
style: sync GitHub Corner colors
fixes#12349.
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: sync site GitHub Corner colors
Always use WaitOnAddress on Win10+
`WaitOnAddress` and `WakeByAddressSingle` are always available since Windows 8 so they can now be used without needing to delay load. I've also moved the Windows 7 thread parking fallbacks into a separate sub-module.
